Here is a list of all the postings Pete has made in our forums. Click on a thread name to jump to the thread.
|Thread: Tail alignment and gear handle play|
Hopper has injected some proper technique and much needed logic into this thread. There's been a lot of other good information posted also. My apology's but I do think my post might get a bit long winded.
I fully understand the OP's desire to adjust his lathe to get the best accuracy possible. I did the same with my little Emco compact 5 lathe, but I did so only after reading that Conolly book more than a few times until I understood as much of the techniques as possible. And most of what's on these hobby forum's is incorrect compared to what Conolly or Schlesinger have to say. I also got fooled for more than a few hours of wasted testing with a light weight dial test indicator bending a quite heavy mounting rod under the effects of gravity. That's all too easy to miss to be honest, and there's really no simple way to know for sure that gravity is or isn't affecting your results when swinging a DTI from the head stock. What I do now is turn a piece of scrap down to within .001"-.002" or the same in metric of either the tail stocks barrel's outside diameter, or the outside diameter of a morse taper blank arbour that fit's the tail stocks female morse taper. You then measure both of your plugs diameter and the tail stocks barrel or arbours parallel section.as accurately as you can with your very best micrometer. Then you use both the lathes carriage and the cross slide to run the finger of a .0001"s reading DTI across both diameters at both the head stock and tail stock. Simple addition or subtraction to account for any minor difference's in sizes for each diameter will then give you the exact numbers of your tail stocks position. I don't know of a simpler or better method that is any faster, more accurate, or easier to do that you can then be 100% positive your test numbers aren't being swayed by those gravity effects.
But the tail stocks centerline height is just only one single check. Just as important you also need to use that DTI to check that your tail stocks barrel isn't pointing to the left or right, uphill or downhill, and if that barrel move's it's position between locked and unlocked, or extended and retracted. Some will say it's only a mini lathe so what's the point of all that? Well it's impossible to try to compensate or correct for any errors if you don't know if they do or don't exist, or even how much those errors might be. And unless your test numbers are 100% repeatable, then your methods will be highly suspect to the point of being useless.
Machine tool alignment, and especially lathe alignment and and that mostly misunderstood "lathe leveling" is probably very close to the number 1 topic on almost any hobby machining forum out there today. And FAR TOO MANY will try and answer to the best of there ability what they think is correct. Yet the majority are basing those answers without taking the time to at least read what both Schlesinger and Conolly have to say, and who ARE those recognised authority's on the subject. Schlesinger's alignment and test procedures are available for free on the net. Possibly the Conolly book might be also. But almost all of us should be able to get a copy to read of the Machine Tool Reconditioning book through something called the "Inter Library Loan" system. I do own my copy, but it is almost $100 to buy it even today through Industrial Press. The book is boring to the extreme in large parts of it, but it will properly educate you so your answers in threads of this type are logical and well thought out reasoning. (Or at least I hope mine are) But in my opinion buying that book was the very best $100 I've ever spent on my shop and education about this so I finally did understand what the actual requirements really are. The subject is vastly more complicated than most understand I think. But those who haven't read it and then understand what's required are pretty obvious when they recommend (with the best of intention's) methods that are incorrect in these threads.
Lapping slides etc. is or would be just one example, yes it will make things much smoother, but there's zero control over exactly where and how much material your removing. Very light lapping can probably work after your initial corrections have been done Trying to maintain or even correct the alignments on a lathe in all 3 dimension's at the same time can't possibly be done by what so many say you should be doing with just that slide lapping. In fact it's all too likely your actually making the accuracy far worse unless your extremely lucky.Scraping and using some very expensive and reliable test equipment, along with a whole lot of logic, knowledge and experience would be the correct and best method. You can of course make a machine a bit better fairly cheaply, and the more skill you have will make your results better. None of this is just my opinion either,those are just the simple facts if your willing to put some effort into researching exactly what is involved.
We really should in my opinion be using these forums as a way to help educate ourselves. But they shouldn't be the only place your basing that all too important self education on. Yet today I see the problems of incorrect information on these forums as a large and growing problem. It should be exactly the opposite. Anyone ever wonder just how M.E.'s or the American term of HSM educated themselves before the internet was invented?
My sincere apology's for the length of this post.
|Thread: Fly cutters|
A cutting speed of 100 feet per minute is the MAXIMUM recommended speed while cutting mild steel with the usual HSS. Just remember that is the maximum. Much better to drop that a touch to make the tool tip last a lot longer between sharpening's. A 10% reduction will make the tool tip last much more than 10% longer. It's not directly proportional. And you could use 3.1416 or even a closer number for pi, but to make it easy to do in your head, I just use the tool or part diameter and multiply that by 4. So a 3" diameter swing tool or part X 4 = 12" or 1 foot. 100 rpm would then be the maximum rpm to give you that recommended 100 ft per minute, or whatever metric numbers that are the same. Very few of the smaller and cheaper offshore built machines today come with a low enough rpm to hit that number once your tool diameter or work piece on a lathe starts getting a bit larger. Sometimes all you can do then is to go to a carbide tipped tool. Some carbides depending on the exact material can do 300-600 ft per minute with mild steel, and some specialised carbides can today do over 1,000 ft per minute with very expensive and rigid machines. Aluminum can be cut depending on the alloy at very high speeds, almost to the point of being unlimited rpm within reason with good industrial grades of carbides, or even ceramic, and diamond tipped tooling. Those materials are very brittle, can't take interrupted cuts even as well as carbide can, and require those industrial very rigid machines and multiple part production to justify there high costs.
Knowing or at least having access to a list of the general and recommended cutting speeds isn't optional. Burning up hard to resharpen at home tooling can get really expensive. But all of those cutting speed lists are for high quality industrial machines and tooling. You'd be far better off to understand that and cut back on those speeds at least a bit. Our time in a hobby is cheap, and the tooling fairly expensive. In industry it's just the exact opposite, so tooling is run right to the limit of cost effectiveness.
|Thread: Help please with this oiler|
Almost "NO" machine tools will ever use grease at any point. There are of course a very rare few that do. But you'd certainly do far less permanent damage to any machine tool by using oil in place of the grease. Going the other way and using grease in place of the proper and recommended oil will accelerate wear at all points at least 10 times more than that proper lubrication would. And being really stupid and pumping grease into something like a Bridgeport's head because some do have a grease zerk on the side of the head can literally cost you thousands in replacement parts and even just to clean all that grease out so you can then use the correct high speed spindle oil.
Exactly why do far too many hobbiest's insist on using oil and even far worse that grease lubrication that's 100% completely wrong for there machine tools? Yes any oil is better than no oil, but the correct and especially that correct way oil is far better than any other oil at all, and most definitely any automotive or even worse the high detergent motor or transmission oils. We all, or at least most of us have to scrimp and save just to buy our machines and tooling, and the total spent can be very high. The proper way oil or spindle oil is literally only a few pennies per use, yet some insist on using some of the worst possible ideas for lubrication just to pinch a very few of those pennies, and they then greatly accelerate the wear on a comparably expensive machine tool. Proper way oil DOES make a noticeable difference to the way your machine operates, feels, and even just how well or tightly you can adjust it's gibs, yet it still allows a smooth movement. No properly run commercial machine shop would ever use anything but the correct and recommended lubrication because they've learned that the incorrect lube just isn't cost effective. And some of what's used by hobbiest's that think there far smarter than the lubrication engineer's or machine tool manufacturers is most likely far more expensive by volume than the correct lubrication would be. In small quantity's that WD-40 certainly is.
Anybody here think this isn't a very expensive hobby at any level and size of equipment? It is if that's somehow news to you I'm sorry to say, and doing things correctly including that proper and specific lubrication is just a very small part of the total cost's involved in this hobby.
I learned very expensively just how little I knew about machine tool lubrication when I mistakenly thought a heavy duty hypoid 90 weight gear oil would last and work much better than the light weight factory oil recommendation would do. Because of the oil drying out and a collection of wear particles that weren't being flushed out of the power feed assembly with that light oil, it then created enough drag and burned up a $800 Emco motor on my lathe. Today I use exactly what the factory recommends and have never had another problem. I'd hate to see anyone here relearning the same very costly mistake I did.
Edited By Pete on 27/06/2015 01:08:42
|Thread: Lathe design not keeping up|
Well I'd sure have to agree that the current lathe designs at the lower to mid range end of the manual machine market aren't or haven't changed much at all in the last 50 years. I do suspect that's about to change, or at least I hope it will, and fairly soon though. Volume production of at least semi CNC machine's shouldn't be much or maybe any more expensive than what it takes to build and add a Norton style gearbox and the two axis power feeds. Add a built in DRO like Tony has already mentioned, and then tie it's positional feedback into the CNC for a very accurate location of the tool tip. So you could then use fairly inaccurate and therefore much cheaper ball screws and nuts. Even any future wear on the screws and nut's should be able to be accurately compensated for. Just let the CNC map the steps against the actual slide movements that the DRO is measuring.
Tormach brought out a pretty simple and fairly cheap semi automated CNC surface grinder last year? Instead of needing a heavy weight, noisy, and quite expensive hydraulic system to give you the really useful reciprocating table drive and user pre selected automatic step overs in the Y axis, it's set up as a simple but limited CNC with an easily programmable system to input your parameters for what you want for table speeds, distance, and feeds. As far as I know the Z axis is still fully manual, but that should be just fine with those smaller surface grinders. Use the same idea with a 2 axis semi CNC drive and a GOOD and ACCURATE rotary encoder on the spindle with a really well designed and rigid lathe and there's your screw cutting system. Plus with almost zero extra money you could have the constant surface speed (CSS) for facing larger diameters that's already available on a few higher end manual lathes that have the Newall CSS feature on some of there DRO's.
Exactly why we don't yet have this yet? Probably because were just not demanding it in large enough numbers yet that one of the larger dealers such as Grizzly is willing to take a chance and requested one of the better factory's to start working on a new design of this type, and in a variety of sizes. With what it's capability's would be, then there's not many manual machine users that wouldn't want something exactly like this as long as the prices could be kept in check. Make the inputs user friendly, fast, and dead simple, and then even the smaller one off jobber shops just like John's would be wanting one. It's even not really much past today's more usual lathes that comes with 2 axis power feeds.
|Thread: COLCHESTER STUDENT HEADSTOCK ADJUSTMENT|
I email with multiple people on almost a daily basis. One who is a working industrial designer and certified machinist, he even owns a Colchester Chipmaster. And one who's a barely retired professional machinist after 50 plus years in the trade, and is in fact a more than well known Model Engineer. One of the best today in fact. I'm not saying this to brag, I'm saying this because I can hold my own with these people.
I don't need to SEE one of these lathes at all. I've been around lathes that had at least 30' between centers. I already know what a heavy well built lathe is quite capable of. Just because I don't own one doesn't mean my points are worthless. I said and I 100% meant that ALL lathes work on the exact same alignment principals, and it's very much pointless about who built it if it's a half decent machine. Hugh's is by being a Colchester a well made machine. That part is unquestionable.Just how good it was built and how well it's aligned right now is the question. In a way I can see your point about that bar test. I've done that more than a few times. Even Emco shows it in my manual. But material deflection could easily fool you just from the sharpness or lack of on the tool point. A poor set of chuck jaws could even sway the results. You didn't read or at least fully understand what I tried to explain. That facing test is only the very first step, It will prove 100% one way or another that something is out or it's not. If there's something wrong in the numbers, you can then start looking into further areas. It is possible that an incorrect cross slide alignment or even wear could change the results.But after that test you then might start going to your two point bar test over say 6" But with what I've learned the extremely hard way, I don't and won't ever depend on one single test or method. You could easily mistake a bed twist for a headstock misalignment without some prior experience with your bar test. Your bar test does work, but just like my facing test, there can be other factors that could change your test results.
And You and I may know about that facing test, but I've yet to see it ever mentioned on any forum like this.
My current home won't work with a concrete slab under my little Emco. But that doesn't prevent me from desperately wanting one. I did at one time have my setup on a proper concrete floor, and it spoiled the hell out of me. I didn't fully appreciate what I had then.
Edited By Pete on 08/06/2014 02:16:56
Edited By Pete on 08/06/2014 02:28:59
Edited By Pete on 08/06/2014 02:30:27
|Thread: Lathe advice... I guess I will need one soon|
For what your wanting to do Jamie, then right now there's no real need for industrial type machine tools. But as I said, if you stick with this it's natural and all too likely you'll end up going towards the larger more industrial equipment. It's almost impossible not to do so. I started out with a little 65 lb Emco compact 5 lathe with the rear mounted milling head. I still have that equipment, but my larger lathe is now one of those 450 lb 280 VF's, and my mill is a 3/4 sized 1100 lb Taiwan built baby Bridgeport clone. I think I could have saved a huge amount of money if I knew then what I think I know now. And my equipment choices today still would have been larger if I could support more weight in my shop. Funny enough, I just mentally added up the costs for the first time, and what that little Emco lathe and mill cost me along with just about every accessory Emco built for them amount's to just about what my larger lathe and mill cost me. I'm well within a $1,000.00 of that figure at least.
Most entry level people don't know that the actual machine tool cost is almost incidental. And the tooling unless you get into some more than larger industrial sized equipment stay's pretty much the same cost. Milling machines are a good example of this. The tooling that fit's and is used on say something like a Seig X2 type mill will also fit and can be used on a Bridgeport sized machine.Lathes are the same, so if you can possibly do it, then saving and buying the largest equipment you can will with some luck delay replacing it for larger a little longer. You need to figure out your largest diameters and lengths, maybe add 25%- 50% to that number, and that's the size of equipment you need. I can say that most new machine tools we can afford does not have a built in low enough speed. It's a bit frustrating when your trying to do larger diameter work and even carbide is burning up because you can't get a low enough rpm.That's when the larger 3 ph equipment starts to make some sense.I've never once regretted buying my 3 hp 3 ph mill. Adding a VFD just makes it really nice to use.
|Thread: COLCHESTER STUDENT HEADSTOCK ADJUSTMENT|
Some interesting life experiences
I took the time and jumped over to the lathes UK site. Hugh's lathe is exactly what I expected, a very desireable and good quality British built machine tool. But it changes nothing about what I said. Obviously we both know all lathes are set up, aligned, and work to a standard set of very well understood basic alignments. It's impossible for them to perform to the level of what we expect if they were somehow "different". But I do respect and appreciate that you do have what seems to be a great deal of hands on experience with the Colchester machines. That alone makes my points a bit suspect.
And I lust after anything that's got a DS&G lettering cast onto it. Even more I'd like due to my recent finds one of those Holbrooks. Just possibly an even better machine than the DS&G's.
But, I didn't say it was impossible for Hugh's lathe to be out of alignment. It may well be. What I do disagree with is the automatic assumption by far too many on these forums that it's always a headstock misaligment. Going by your experience, then you'd have to agree that far too many just jump to that conclusion without fully checking the rest of the machine. But now with your additional experience and information, then yes it makes it slight bit more likely that Hugh's headstock might need a proper realignment. But .................................I did give him a test method that will quickly prove what direction he might need to go. If that facing test is even close to the factory allowable specifications, then there's no need to adjust the headstock.
Maybe in a way I worded and wrote my post due to reading far too many other posts where the adjustment of the headstock is the first thing mentioned. I still maintain it should be the last thing you touch until you've proved it is in fact the headstock that's out. That facing test I mentioned isn't obviously 100% reliable because it's a combination of the head stocks alignment and the built in alignment and wear on the cross slide. But it will help to pinpoint where the problems are or aren't. It's exactly where I'd start, but it's something I've yet to see even mentioned anywhere else.
FWIW, and it doesn't mean that much to this discussion. I started out with a little Emco Compact 5 lathe when they were still being built in Austria. I got deeply interested in why I was getting tapers on long parts. Not very much of a taper, but enough I didn't and wouldn't tolerate what I found. So I bought Emco's add on accessory, they call them "leveling plates". Those still didn't give me what I wanted on a wooden bench top, so I then mounted my little lathe to a 1" x 12.5" x 28" long mild steel plate.It was only then I could see just what this little and fairly cheap lathe was actually capable of. Unfortunately my shop floor isn't concrete, and due to it's standard stick built 2" x 6" floor construction, my methods aren't even close to being permanent. I can and have proven using a brand new Mitutoyo 2" digital mike that it's possible to adjust this lathe by leveling the lathe bed, and then making very slight adjustments after that where I can turn a 2" x just about 12" long shaft to under .0002" taper from end to end. Now if I shift my feet on the floor or move at all it shows up immediately in the size. The settings can't and don't last more than an hour or two due to temperature or humidity changes. But those accuracy's are possible with a bit of skill and knowledge. Maybe more than a bit of luck helps too.
|Thread: Lathe advice... I guess I will need one soon|
Most likely it would be better and much more kind to lie to you. But your should resign yourself to the facts that you will never ever be finished buying tooling for a mill. A lathe is slightly better though. How much is your budget, and how much electrical power and room do you have?
Your mill is a fairly decent machine to start out with, and far larger than my first mill was. Motorcycle work? Leaving aside anything like engine work and cylinder reboreing etc. Then your wanting to do mostly parts replacement and that customisation, and then maybe building up to parts such as disc brakes for diameter. Single phase motors on machine tools are ok, but a real upgrade later on is using proper 3 phase equipment.. VFD's today make this more than within reach and very much worthwhile.
FWIW, your current mill probably won't be something you stick with, but it's a great learning tool, with some luck it's also a common taper like a R8 so the tooling can be transfered to a larger mill when you do upgrade. Your lathe will be exactly the same idea. You will if you stick with this upgrade to larger equipment in the future. Everyone does. So for right now if you want to buy new? I'd suggest something like a 280 V-F. It's rebadged by numerous dealers and is possibly built by Weiss In Nanjing China. There's obviously far better and larger, but this would be a good learning tool. Given some experience and knowledge, then you might then start looking at the better quality used industrial machines. That does require that experience and knowledge before you can even judge exactly what you need or want. But most tooling you'd tend to buy for something like that 280 would be useable on another machine. Tailstock tooling and the smaller MT tapers wouldn't transfer though.
But the very best advise I can offer is if you think you'll stick with machining as a hobby for even the next 10 years? Then please save your money and buy the very best industrial grade cutting tools and measuring equipment you can afford. In the long run it's the cheapest bang for the buck. There is no such thing as good cheap durable cutting tools. The much more expensive industrial tooling cut's, performs and last's far beyond the extra expense involved. And if you were to add the word accuracy, then the same can be said about metrology equipment.Think about it,if you can't measure it dependably and repeatably, then you can't build it to the required accuracy. I tried the cheap cutting tools and measuring equipment, I can't afford to buy it anymore.
|Thread: Gripping Drills in Chucks|
I'm sure you understand it's more than tough to properly sort out a problem like this without being face to face and putting your hands on it. So for whatever it's worth you have my sincere sympathy. We all know mistakes and factory defects can happen with even the very best manufacturer's today. There's no doubt Albrecht can and does produce the odd factory dud. But for your problems right now, I think it's fairly safe to rule out your Albrecht chuck. And since it's at least fairly new, and you've used the tightening methods we've suggested, then your looking either at a contamination issue, or the actual quality of the drills your using. Something has obviously and drastically changed, At one time as you've said you didn't have any problems. So..........................what have you changed that might produce this problem. Maybe I'm totally wrong, but I'm suspecting the drills themselves. There no different than anything else. Defects and mistakes happen. But again something has changed to produce this problem. A cutting oil change maybe? I just don't know and can't suggest any other logical reasons.
|Thread: COLCHESTER STUDENT HEADSTOCK ADJUSTMENT|
And after some more thought Hugh.
There is a fairly quick method of giving you a quite good idea about your headstock's actual alignment using some simple test equipment. You can do all the precision test's and alignments you'd like. But the bottom line is just how well the machine performs under real world cutting conditions. Anything else can't and won't prove all that much. The finished parts and just how true and accurate they are show the machines actual alignments.
I know zero about your lathe, but they all work to the same basic design principles. All good lathes should be setup at the factory so the cross slide will cut a very shallow concave angle while doing a facing cut. Standard commercial quality lathes have a larger allowance for this than tool room quality lathes. If? I remember correctly. Tool room quality lathes should be set up and produce a concave cut of around .0015" over 12". My memory could be a bit faulty about that specification though. The exact numbers aren't that important for what you want to really test though. But that concave is ground in to the machine so parts don't rock as the faces are brought together, and the machine wears into alignment not out of alignment as you use it.
Since I haven't checked the Lathes UK site I don't even know what your lathe looks like. Do you have a faceplate for your lathe? Does your lathe have power cross feed? Or do you have a piece of scrap plate as large as you can possibly swing? Any of that will work for this test.
Bolt or thread your faceplate to your spindle, or figure out a way to attach and face off a plate to the maximum diameter your lathe is capable of. Ideally you have power cross feed. But it could be done using a hand feed. You want the slowest feed yet very best surface finish you can manage across the whole face until it cleans up. That will replicate the exact alignment your headstock has to at least the cross slide's way alignment. Now, you need to set up a good accurate and 100% completely dependable DTI on your lathes cross slide with the DTI's finger against the part you just faced. You do not want to check that faced part by running the DTI finger from the parts O.D. that's closest to you into the parts center. All that does is follow the cutting tools path and it can't and will not prove anything. You want to set the DTI's finger at the parts approximate C/L and then use your cross slide to run the DTI's finger across to the furthest point away from you. That would be towards the lathes rear bed way. The variation you record on the DTI dial will be twice as much as the lathe actually cut's. It's an extremely accurate way to at least test the cross slides alignment to the headstock's alignment. Longitudinal turning or finding a taper while measuring that longitudinal cut could show a taper due to many other reasons. But the test above should give you a very good idea if your headstock is misaligned or not. It would be without question my first test for your lathes basic headstock alignment.
Edited By Pete on 07/06/2014 20:42:41
In my opinion I would be extremely careful and more than a bit paranoid about doing anything as radical as resetting a good quality lathes headstock without exhausting every other possibility I could think of about exactly why your lathe is turning a taper like that. This is again another method that's very much recommended by people who just don't fully understand or appreciate how intricate proper machine tool alignments really are. I barely know enough about it to know good advise from bad. But this is not and never will be a cheap hobby at any level. The equipment, tooling, accessories, and even the room it requires adds up very fast. Even the information, skills, and knowledge required alone to get any good at this is staggering. So your first stop needs to be finding either a new copy from Industrial Press of the 1950's written book called "Machine Tool Reconditioning". And no there hasn't been anything newer than that 1950's book written in the English language. And a brand new version is still going to cost you right around $100.00. And it's also not knowledge that forums like this can provide for free.
Or it's either that new version, or maybe if your lucky you might find one on Ebay. It's also an extremely dry and boring book to read. It's not at all imho optional for what your trying to do. Most of the book goes into great detail about exactly how to rebuild various machine tools to brand new or better alignments. The books contents are even too complex to properly explain here. But over and above the hand scraping information, it will give you the basic knowledge and understanding of good machine tool alignment, and I can say it doesn't start out by beating on spindles as an adjustment method. There's possibly dozens of reasons why your machine could be turning a taper that steep, and unless your lathe was hit really hard, or dropped, then adjusting the headstock is the very last place I'd adjust until I'd checked everything else. Good machine tool rebuilder's start out by doing what's called a " machine tool survey", this is basically a series of tests using mostly a micrometer and DTI to do most of it. Having a very expensive precision straight edge would be another required tool for some of it, but a GOOD micrometer and that DTI can prove a lot. They pretty much follow the German Shlessinger (sp?) developed machine tool tests. And while that information is online if you dig for it, you still very much need the book I mentioned to understand exactly what your results and test numbers mean.
And as a extra bonus, even if you never ever rebuild or adjust any machine tool, the book will completely change your opinion about just how clean or how well lubed you keep your machine tools ways. That alone has more than saved me the cost of the book. I'm certainly not saying it's impossible your headstock needs a realignment, but I am saying it's probably around 99% it doesn't need it.
And for anyone who wants to say I'm wrong? I'd expect you to be a machine tool rebuilder, or have at least read that Machine Tool Rebuilding book so we can use some logic instead of our best guess about this. Hugh asked for some good answers, that's the least he should get.
Edited By Pete on 07/06/2014 19:37:02
|Thread: Using Riffler Files - HOW>|
Riffler files are also very much used even today in the custom gunsmithing trade. Mostly as one of the many tools used for getting in and removing excess wood while fitting the metal parts to the wood. It's a process much like hand scraping machine tools for fit and alignment. Larger diameter surgical tubing (the stretchy rubber type) can be used over the end of the file your not using for the double ended style. Good one's today are more than a bit expensive, so it's well worth protecting them. And excellent quality files of any kind are getting more than a bit tough to even find now. There not at all easy to replace. I'd be very suprised if they weren't used in at least some of the other specialty trades today. Pattern making, maybe very small one's for watch making etc.
|Thread: Gripping Drills in Chucks|
Yes I can well understand your point of maybe loosing some hand strength. Sooner or later were all going to go through this. And even the top quality Albrecht chucks will also sooner or later need parts or a bit of maintenance. But to also state a bit of the obvious, the general rule is the cheaper your chucks are then the less precision there built to. That alone makes them far less efficient at transfering the energy into tightening the jaws. Years ago I had a cheap Black and Decker hand drill that would not hold any drill without slipping no matter how much I tried to get it tight. I finally just scrapped the whole drill since it wasn't built to a high enough standard to deserve replacing the chuck. But you haven't said how old or what quality your chucks are.
You did mention a keyless, so even if it was a brand new Albrecht and your hands just aren't strong enough now to properly tighten it, you could if you were a bit careful use a good quality strap wrench on the body. And by good quality I mean one that comes with the proper leather strap. That would provide the most bite and protection. And just like adding a snipe to a chuck key, you would have to be a bit careful about going the wrong way and over tightening. But any of us should be able to estimate how much to tighten a chuck just by feel. It's also been my experience that once a drill has spun in a chuck it's scrap. It's even more likely to spin again for some reason. And the burr raised plus the displaced metal on the drills shank is reason enough to throw it away. They can't be fixed with the equipment most of us own. So for what good quality drills cost today, it's well worth the cost to buy very good quality chucks, or rebuild the worn good quality chucks you might already have.
I doubt it, but just to double check and make sure. You aren't trying to use any solid carbide drills are you? They can and will tend to slip in the normal chuck jaws. They use diamond plating on chuck jaws that are designed for carbide drills to give them some grip. I still have most of my hand strength, and it's a lot slower method. But when I want a very very accurate location and I don't want the drill to wander, I use an ER collet to hold the drill. It's a vastly noticeable improvement, and far more rigid way to hold a drill even comparing it against an Albrecht. Something like that might be worth considering depending on what you have your current drill chucks mounted to. Most drills would break long before they ever slipped in a properly tightened ER collet.
|Thread: Sieg C3 Chuck run out|
Ady 1 is more than correct about seeing much or any mention about chuck runout in those old M.E. magazines. But I'm way too lazy to retype it all again. If your interested enough, then please have a read through of what I just posted in the "Square Top Colch / Student" thread in this same sub forum. Since both threads are a bit alike I couldn't make up my mind where to post the information.
|Thread: square top Colch / Student|
OK, I think that's more than enough about what you should expect from our type of standard 3 jaws.
Just like a lathes ways, the chucks scroll and jaw teeth will slowly wear over time and at varying points depending on the size of work you usually use it on. The jaw tips can also wear from work moving around inside the jaws while the chucks rotating. A shaft with a slightly offset center drilled hole with the tail stock center supporting that end can make the work move around for example. No it's not very much, but the work can and will move. The slots and grooves that the jaws slide on also wear. Depending on the hardness, either the jaws or the chuck itself, or even both parts can also wear. But it's very important to note that even the best chucks in the world have clearances built into them right from the manufacturer. Without that very small but important clearance it would be impossible for the jaws to be adjusted.
So, you have to either regrind your chuck jaws or replace the chuck. New jaws can be bought if your chucks a good one and still being made, but that doesn't address the chuck wear. There is only one single method of chuck regrinding I know of that does provide a proper way, and even more important the proper DIRECTION of pre loading those chuck jaws so they can be accurately ground. And it's certainly NOT shown in that YouTube video. In fact it's physically impossible for that method to work and give you correctly ground jaws. Those plates with the clover shaped design cut in it are the only way I've seen yet that allow the internal jaw tips to be ground straight. Due to those built in clearances every chuck has, the jaws tilt a fraction of a degree in each direction depending on which side of the jaws your using. It's not a manufactuering defect they do this, it's just how the design works. So you have to load those jaws and grind to compensate for that jaw tilt to end up with straight jaw tips that grip there full length.
But there's a bit more to this than it first seems. Unless you go the extra mile and do the very best you can while machining that plate you won't get the best accuracy, and that defeats what your trying to do. That plate really should be at least the same thickness as the jaws protrude from the chuck's face,and have properly bored holes with an excellent bore finish so both sides of each chuck jaw bear evenly on it. Just using simple drilled holes could be enough to slightly shift the jaws. Boring those holes is the minimum in my opinion. Regrinding the jaws in a well made chuck is precision work, and it should be treated as such.
So to back this up even more, your very first step is to tear your chuck down to it's basic parts for a thorough cleaning. On good chucks, you should mark each and every part so during assembly all the parts are returned to there exact same position. That's especially important for the pinions. Any chuck that has that mark means that pinion is the master location that the chuck was originally ground to by using it. And using a bit of logic, your going to need to repeat that chuck dis assembly and again clean it after grinding the jaws. So there's much more to doing this correctly than far too many posters understand.
But if you read what I've tried to point out, you should be able to understand that even top quality chucks aren't and can't be all that accurate. But no matter how expensive or cheap your chucks are, it's very important that the jaw tips are square to the lathe ways. If there not then smaller work can and will flex away from the tool tip.
I hope now you know what took me a very long time to research and learn. And none of this are just my opinions, if you care to research it enough, you'll find the same information I did.
Edited By Pete on 07/06/2014 15:28:37
|Thread: Collets help|
No problem Gordon, but I did want to double check as you might have had something I've not run across yet. But one thing you might want to watch for, single point threading put's a fair amount of pressure on the part, so doing something like that without much tightening torque could very easily push the part back into the collet. Just one more little detail to trap us.
I think you might mean either a ER 25 or ER 32 for your collet size. The main reason I think people have for something like endmill's being pulled out of the ER style collets is they just don't know how high the torque requirement's are. My ER 40's need well over 100 ft lbs of torque on the nut. Almost 130 ft lbs if I remember right. But for tool holding, hand tight or a bit more isn't going to do it. You certainly wouldn't want a razor sharp endmill dropping out of the collet at high rpm.
Yes those are Deckel collet's. As far as I know Deckel still make and sell them. Better be sitting down before reading the price though. I seem to recall there might be some cheaper copies around but can't remember where I saw them for sale. Maybe RDG Tools? And if you haven't seen it yet, going to www.lathes.co.uk and then clicking on the Deckel link will get you a lot of further information. I can't say for sure if those G.A. cutter grinder collets are the same or not. But someone here will know for sure. And it would be hard to find a better mill than yours imo.
|Thread: Myford Super 7 Inverter Drive|
I've got a 3 hp 3 phase mill that's powered with a VFD. Some people seem to use that inverter term though. FWIW, You should see an almost unbelievable difference in smoothness of the motor drive, it will also be quieter, and your surfaces finishes should be much better. But, I don't agree with over driving any machine tooL much past it's factory design limits. Yes it can be done, but is it a good idea? Your bearings, spindle and pulley balance, and even the materials there built from were engineered on good quality lathes to operate at a specified maximum rpm. The higher you go with rpm then the steeper the cost curve gets as far as wear and parts replacement. They build and sell specialized very high rpm rated lathe chucks ranging from hardened steel into I'd imagine some fairly exotic light weight ultra strong aircraft grade materials for very high rpm work. But those specially balanced high rpm steel chucks alone have prices to match. Yes I know you said you were planning on using collets, but I'm trying to show how expensive something like this can become, and how quickly it can start to add up.
Unless you do a great deal of very small work the costs to do this may not be worth it. And an inverter or VFD or any currently available pure electrical method will not give you full motor torque as you lower the rpms. That still requires it to be done mechanically. Whatever you do there's always a trade off that has to be done. IMO, the inverter/VFD is well worth it for the variable speeds, smoother running, better finishes, and maybe a very limited use of the higher speeds once in awhile. But if all your wanting is the high speed for small diameter work, then I think I'd be looking at something like a spindle speeder that will give you a way through gearing to increase the part rpm without increasing your main spindle speeds. And if you really want high speeds, they make very specialized air driven turbines that will do well beyond 50,000 rpm.
I have to think that there's not a quality lathe manufacturer anywhere in the last 50 years that would say it's a good idea to increase the spindle rpm by 25% or more over what they designed there product to do. 4,000 RPM today is actually very slow if you look at what a lot of the newer CNC equipment is capable of. The difference is it's designed from the start to do so.
And I've yet to operate any Super 7, but does yours have a proper roller bearings at both ends of the spindle, or is the front bearing the usual drip fed oil lubed solid type? Burning up a bearing and/or spindle journal could get a bit costly. I'm certainly not trying to say your idea is wrong, but there's a lot more to this than just replacing the motor on your lathe.
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