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Member postings for Ramon Wilson

Here is a list of all the postings Ramon Wilson has made in our forums. Click on a thread name to jump to the thread.

Thread: Boring Question
11/02/2010 09:39:20
Yes Merrick, very rarely venture into the top range unless it's something really tiny.
Coolant is a problem with tips very much a case of all or nothing. Ian's right the Haas machine pumped it out at some 14 gallons a minute if I remember right - three outlets simply throwing it on. Because of this need (and the ability to contain it) all carbide tools - lathe or conventional mills - were used dry. Blue chips and stand well back! I expect there are quite a few reading this will remember having the odd hot blue spiral smack them on the cheek and stick just under the glasses.!
I remember the uncoated Seco tips well, they were always preferred for the Clarkson Hi-Flo milling cutters and on the lathe for mild steel - they always outlasted other types.
Because of the way they were used I have never felt the desire to strain the Myford and the mill simply isn't up to it. Hence their limited use at home.
Just going back to the 'Throw - Away' FC3 bits a moment
I totally agree about the need to get up to a shoulder and /or face off but I don't use them for that - the whole object, and the point I was trying to make was that they require very little grinding (from solid) and are ideal for making small cutters for odd jobs -  very small parting off, tiny bores, o-ring grooves, screwcutting tools ad infinitum. Once the FC3 cutters are of no further use on the mill, if a cut off wheel isn't available then a quick nick on the edge of a grinding wheel at the start of the flutes,  the flutes held in a vice, and covered with a bit of rag before snapping off with a hammer. Ergo free 6mm or 1/4 round HSS.
Putting the need to turn to a deep shoulder aside - I tried this from fresh the other day - straight forward left-hand turning tool - 12mins for 5/16 square HSS and  just over 2 for the insert. It's not so much the time but the dust and heat build up. I accept the HSS insert won't get as deep or as close as the 5/16 blank nor will that get as deep as the carbide tooling, but they are very useful when you need something quick to advoid having to grind relatively much bigger lumps of HSS. It's offered purely as a help to those
whose budget might be slightly 'restrained' as well as being a good way to use something otherwise 'thrown away'.
I've yet to try the Tangential tooling though I understand the principle - sharpening being very simple to achieve. I guess we all have our old habit's though. Good we're all different .
It's cold and miserable outside - guess I'm off to the workshop then
Have a good day in yours
Kind regards - Ramon

Edited By Ramon Wilson on 11/02/2010 09:42:49

Thread: Nova 1 compression ignition engine
10/02/2010 23:01:14
Hi again,
Just like to add my friend John finally finished his engine and I went over to his today for a twin run. In a word - Magic!
He had made a mount out of a nice piece of wood, the engines were bolted in and the flicking began. Not too good at first but we put that down to the cold - it was a bit parkie with the windows and doors open and snowing outside. Anyway finally got them running - bet his neigbours were impressed - and they performed well.
By cunning reduction of his spray bar diameter his has a much larger venturi area and was doing a consistent 5100 to mine steady at 4000 - his has a nicer beat too so having chided him for already 'tuning it up' it's a now question of 'if you can't beat 'em' etc.'
 It was a good end to a short, very enjoyable project - on to the next? You bet.
Thanks for all your interest on this one back with another I/C soon
Regards - Ramon

PS Often taken for brothers I've known John since I was four years old - I'm the good looking one with the white beard!

Thread: diamond grinding wheels
10/02/2010 22:28:36
Hi All, Some good replies here. At the risk of repeating myself a bit perhaps I should elaborate a little.
As said diamond wheels were only used as far as I remember for surface grinding the cutting faces of punches and dies. Most of these P&D's had very complex shapes the forms of which were wire eroded. The use of diamond wheels was purely down to the hardness of carbide. Prior to the accelerated use of carbides in these press tools  these parts were made from varying grades of tool steel and whilst the more complex were wire eroded many were formed by grinding with conventional wheels. The forms were shaped on the wheels by a single point diamond using an 'Optidress' wheel forming attachment.( Big panic when you hooked the diamond out of the end of the dressing 'stick' !) The forms took many different shapes of angles and radii all dressed in this way. To give an idea of the limits of dressing involved it was frequently required to dress a 1/4 wide 6" wheel down to a thin blade with a .8mm (yes that is right) radius on the end. (That form had to be 'dropped in' some 16mm which required an awful lot of re-dressing as the wheel glazed up) Sorry for repeating myself - the wheels came in all sorts of grades, bonds and hardness to allow this to be carried out. I mention this to give you some idea of the (relative) ease of which conventional abrasive wheels can be shaped - not to suggest you do it - or even need to do it - at home but if you have a T&C then this is going to be a lot more beneficial to expose new clean grit than not being able to shape a diamond wheel.
Merrick is right to say these are finishing ops or to put it another way if you do intend to cut from solid - eg HSS blank for turning - then you need to take your time. Grinding is not something that can be forced. I don't wish to raise the dreaded H&S but be aware that grinding wheels are not shatterproof and do rotate at a peripheral speed that will shower lumps of abrasive everywhere at a phenomenal rate of knots - it makes a big bang and you don't get an advance warning! Sorry if it sounds like a lecture but it has to be said - Keep your wheel guards on. Really!  And whilst we're on the matter its not good to beathe the dust created when grinding carbide particularly if you use a diamond. The dust, once in the lungs, does not come out and it's accumulative. I know the amount that the home user is likely to be exposed too is very small, probably very very small - but it's a health issue that you should really be aware of.
Finally can I just remind you this was ten years ago - the progress since then particularly in the use of carbides and wire eroding has made these techniques very much a thing of the past. Things have moved on - I just haven't so don't beat me up if I'm off the mark!!
Thanks for the info on the diamond dresser - I couldn't open the pics on the link but the price was much better than anticipated. This is the type I mentioned, I guess the Chronos one will be similar, as you can see it's on it's last legs so it's good to know I can replace it.
Hope this helps a bit more
Regards - Ramon

Edited By Ramon Wilson on 10/02/2010 22:32:28

09/02/2010 23:55:37
As I've said it's quite some time since I was involved with these matters but unless things have changed this was how it was -
Our press tools were made up of individual parts made of hardened (various) tool steels or carbide. The diamond wheels were only used on the carbide and never on the steels. I was not involved with the carbides but I recollect the wheel was brought down on a 'block' of some material which trued the wheel and removed any detritus.
The tool steels were ground with a myriad of wheels - sorry but I can't remember all the grits and grades but most were white for form ginding ranging from soft to very hard, brown 46J for basic surfacing and/or roughing, pink for the really hard chrome steels. These wheels were all dressed regularly with a diamond held rigidly in a holder on the chuck or in the optidress wheel grinding attachment. All well to the rear of the technology queue now I guess but it may have relevance.
All of our diamonds were 'single point' of varying carats but someone at some time gave me a very small piece of diamond impregnated steel section about 12 x 6mm. This is bolted to a piece of steel for a crude handle. I have no idea what it is called or where to get it from but it is absolutely the best thing for hand dressing abrasive wheels - as the steel grinds away fresh diamonds are exposed - I used it only at the weekend to trim the wheels on the off hand. I'll take a pic of it tomorrow so you can see what I mean.
It's getting rather short - if you know where I can get another I'd be grateful
Hope this helps -  Ramon
Regards - Ramon
Thread: Boring Question
09/02/2010 23:25:25
I really wasn't trying to teach grannie here Merrick, but re-reading your post it seemed to infer you were (having chatter problems that is).
Whatever, I'm surprised on the chatter bit using 'between centres', can't recall having had a real problem with that type of op so far -definitely not on finishing cuts but have on occasion had to deal with it when holding in the chuck. I agree that the centres can be a source - they should be as large and as deep as they can be for the bar. I've not tried the chuck driving method so can't comment but as long as it's running fairly true would have thought that that would go some way to help stiffen the bar. Biggest bar I have used  (on the Myford) is the larger in the pic - 1" diameter.
I did make a booboo when I said the 'jacking' screw could be left in. It has to be removed of course to be able to measure across the bar. That does make it a bit fiddly at times but I have found the result worth the extra little bit of inconvenience.
Regarding the feed/speeds you quote I feel this goes to show perhaps that they could be considered a bit overkill for our needs.
If the figures are right - and I certainly don't dispute them - then as average - 'optimum'? figures they make the eyes water a bit not to mention the Myford cringing at the thought.
400mtrs/min equates to just over 1300 ft/min so on that basis RPM for a 1" bore would be 5200 (Using CS x 4 over D) At .2mm/rev that's a feed rate of 1040mm/min or near 41"/min. Totally unrealistic for a Myford - Colchester Triumph 2000 maybe but not a Myford - well not mine that is! Even if this was dropped by 75% when the carbide will be soon be wearing it's still a fair rate to apply by hand. (In order to preserve the leadscrew I never use it to apply anything other that the final finishing cuts and screwcutting of course). The one thing a Myford S7 lacks is a 'feed' screw - what a transformation that would make!!
Today, rummaging through a box of my homemade HSS boring bars guess what I found! A Sandvik SCLCR boring bar no less. Total surprise, have no idea if I bought it, was given it, or what. Probably came home with all my tools. Simply had no idea it was there. Theres aging for you!
Well nothing ventured etc so it was mounted up and tried it on a piece of tool steel at 600 RPM - good but bitty- more speed - one down from top and it was going fine, certainly cuts metal well though the depth was held back to 20 thou. Can't remember the last time the lathe saw 'top gear'. Can't say it will change my views by a great amount but it certainly handled the material ok - I think it will get used again particularly on the tougher materials
I have no power down feed but that may change later in the year says he hopefully!
Regards - Ramon
Thread: diamond grinding wheels
09/02/2010 13:48:06
It's a good ten years or so since I was involved with grinding (not Tand C) but the only time diamond wheels were used was for (surface) grinding of carbide. Diamond 'tooling' in the shape of files, laps burrs and honing stones have moved on considerably though I'm not sure that applies to cupped wheels for HSS - I may be wrong here - just don't want to think you will be shelling out for something that will not live up to your expectation.
I would say that you would be possibly be better off investigating  conventional abrasives and purchasing a really good diamond dresser - wheel dressing is something that needs constantly attending to when grinding fine surfaces whether tools or not.
Hope this helps - Ramon
Thread: Slow loading pages.
08/02/2010 22:44:51
Interesting to read the above - for me it's marginally better than at the weekend but still  painfully slow especially slow when loading from favourites - slightly better using Google. Doesn't seem to be so on other sites though.
Time from hitting the post button to the posting also seems particularly bad 1-2 mins at times. (This one took 35 secs) 

Edited By Ramon Wilson on 08/02/2010 22:47:05

Thread: Boring Question
08/02/2010 22:37:00
Oh that's unfortunate!!!
It appears to run out of words!!!
................ I may become a convert. Thanks for sharing it Ian.
No offence taken and sincerely none intended. Uncontentious discussion and debate should be the life blood of this Forum - a truly super addition to 'our' tooling cupboards.
Regards - Ramon
08/02/2010 22:25:11
Oh gosh Merrick my apologies, to you and all the other readers of this thread, the last thing I want is to be considered disengenuous - truly.
I was merely trying to point out that I had had a Tand C for so long without using it. I do however take your point regarding the work situation. However what I was trying to say was the same as Jeff - there simply isn't the need to have one in order to pursue the hobby.
Believe me I'm not disputing their use or usefulness, but let's face it before the Quorn came along there wasn't much the amateur could turn to. The Quorn of course helped change that immensely and the Stent and other shall we say 'less advanced' 'grinders' even more so. As with most things it comes down to 'money and choice' - horses for courses etc so again I would suggest perhaps we have to agree to differ, and let this point  be dropped now and turn more to the thread.
You say "we have solved the boring question" but  you also state - you find it difficult to avoid chatter ( I guess you mean when boring) so that in itself provides an issue to discuss.
Several factors can contribute to this annoying situation and it's something that needs to be got to grips with before that final cut as I'm sure you will appreciate only too well. Normally a reduction in speed and /or an increase in feed will do the trick, but it's best to find and eradicate the cause if possible. Normally the culprit is a tool that's rubbing - probably on a bar perhaps a bit slender for the bore length when sometimes a big blob of plasticene stuck on the bar will absorb any minute vibrations set up - more ringing than chatter but still enough to wreck a finish (providing theres enough bar to hang it on that is but then if so it's best to get that as short as possible to begin with anyway). Normally though if reduction in speed is not the answer then a good look at the cutting area is called for.
Dare I say it? ......... Carbide (tipped) tooling does seem to be more prone to this than HSS. However I'm quite certain this is normally down to the fact that carbide prefers to 'be worked' at those higher speeds and feeds, something that can be a bit unnerving when you can't see what's going on. As a matter of interest has anyone got the recommended speed /feed/depth of cut for an SCLCR tipped boring tool for say CI and Mild steel?
Boring between centres gives a very satisfactory outcome. It does take a little more to set up than whipping the job in a 4 jaw but not horrendously so. It will give a very parallel bore though and where it really scores is if you have two bores side by side that need to be parallel to each other. I made my first bar to do the Quorn 'feet' and have used the technique for most bores, including singles since. The job does need packing to the correct height though a vertical slide is a big bonus if you have one.
Achieving the correct bore dimension is not difficult either. There are 'attachments' that allow the cut to be put on but then have to be removed. Perhaps you will be interested in my set up.
Firstly a small flat is milled on the bar then the hole for the bit is drilled/reamed opposite this stopping just short of the flat. The flat is then drilled thru preferably 40tpi though mine are just a simple BA. A hole for the clamping screw is tapped in the side.
The distance across the bar at the flat is measured, the radius of the bar subtracted and the result stamped/marked on the bar.  The bore size is the distance across the flat to the cutter tip less the marked distance multiplied twice. The cut is put on by slacking the holding screw to just nip the cutter and, in my case, using the BA screw which, depending on clearance, can be left insitu or removed. It's surprising how fine this can be advanced like this. It can be very accurate if you need it to but of course most times it's for a piston which can be made to suit if it sneaks oversize a bit.
On the first cut of a rough bore the bar does spring a bit and can look a bit 'wobbly' as it goes through but as soon as any eccentricity is taken out it settles down and produces very good bores indeed and yes I'm afraid to say it but you are better off with a round nose cutter preferably with a 45 degree-ish approach angle - but how you sharpen it I'll leave very much to you to decide
Heres a couple of pics of the larger bars and the op on the McOnie cylinder

I guess it's fair to say that I'm not a 'carbide devotee' though they have been used on the odd occasion (at home) but it is interesting to hear Ians success with his method of making bars. I have a old saw blade though no green grit wheel at present but I shall give it a go - who kno
Thread: Hexagon holes
07/02/2010 22:33:42
If I may elaborate on one of the above helpful sggestions.
You state small holes in small gears/wheels. Assuming these are 4-5mm or under then depending on material and the power available to push it through, this can be done, as said, using a hex key of suitable size. However it is difficult to achieve a 'full', flat sided, hex. The fit on the points however will be a good fit on the key.
The hole size needs to be a few thou greater than the 'across flats' dimension. Open the hole at the top to the 'across corners' dimension just enough to position the key. You do have to sacrifice a key here - preferably make a holder by drilling a blind hole into a small length of mild steel a few thou smaller than the A/C dimension and, asuming you are doing this in the lathe, using the tailstock chuck, broach the key in to the holder until it stops.
Putting this holder in the tailstock drill chuck , you can now, if you are happy this will not stress the lathe, use this to broach the hole using the small recess in the workpiece to align it.  A small holder to grip in the chuck to centralise the workpiece if neccessary can also help but the closed jaws may suffice. (you can also use the drill  press but you need to ensure the tool is perpendicular to the workpiece or rather the hole is axial to the  broach). As previously mentioned grind the hex key off nice and square but preferably don't debur and use a good cutting fluid to get the best result.
As said it all comes down to material and size depending on size a fair bit of force is required relative to the small amount to be removed so be careful not to over stress things.
Hope this helps - Ramon
Thread: Boring Question
07/02/2010 21:51:32
Oh that's easy Merrick, I'd jump in the car, nip over to my old place of work and get them to get it 'done' for me.
Now that's not being flippant just a fact because I have just one shell end mill and again used that just once since I was given it in 1980, quite recent too, to do the crankwebs on the Nova engine. I realise of course that that isn't an option that most can take but having said that most small jobbing shops have a regrind service they rely on and I'm sure if approached would be happy to help on the odd occasion such an item needed sharpening. It's how mine was sharpened! One can but ask. (If one can find a jobbing shop these days that is!!!)
However I take your point - but the thread is about boring tools not milling cutters. Of course you need a Tand C to sharpen endmills etc and it will save you a lot of money not to mention control of those specials but as has been stated so far it isn't really neccessary to have such a luxury to actually be able to machine metal. If the average guy hasn't got a decent bench grinder before his 'Tand C' I would venture to think the priorities are a little askew.The 'amateur versus professional', 'God of ME' etc shouldn't have to rear its head, for me it's about helping that amateur get a job done without their as yet to be acquired skills being a stumbling block.
And I really can speak from personal experience here for I began model engineering as a total amateur in 1972 when I struggled, really struggled for several years, to acquire those skills so desired but so elusive. Then in 1980 I gave up my offshore career to begin again and started from scratch in engineering to learn how to make a living as a 'machinist' something I was very passionate about doing. That early period was truly an eye opener for an amateur so I like to think I have not forgotten those roots and can see it from both sides - it sometimes is very difficult for the true professional to understand the dilemmas of the enthusiastic amateur as he takes so many things about the business for granted though believe me, I have seen some very 'professional' engineers make some appaling 'amateur' cock ups but we all make mistakes myself very much included!!.
I can only offer help to others based on what I have done in machining in the past - I have certainly not accomplished any great feat of model engineering - but I certainly won't comment on anything I haven't had any experience of. I hope my intentions will be seen as not to disagree but to offer an alternative in the hope that it helps someone. God, I've just retired, the last thing I want is to be controversial.
Keep on grinding
Best Regards - Ramon
Thread: Slow loading pages.
07/02/2010 15:36:05
Thanks Mark, yes it does appear to be just this website though it has improved slightly this afternoon. I've done the normal things that are in my extremely limited computer bank - defragged, dumped all file and cookie history and ran Spybot and AVG scans. Nothing apparently untoward there. Hopefully it will just be down to 'weeknd drain' on the server. Thanks anyway
regards - Ramon
Thread: Boring Question
07/02/2010 15:24:07
Ahh Merrick you pipped me to the post!

Have to admit that whilst what Jeff is saying is possibly provoking to some I have to agree with most of what he says.
I set out to build the Quorn when it was first published and was well into it when I had the opportunity to purchase a virtually unused Clarkson T&C grinder at a very reasonable price from my works. I then sold the Quorn to well known ME 'toolmaker'  Dr Peter Clarke and then, (after equiping it with an expensive single phase motor), over the next several years proceeded to use it  just once and that was to reduce the diameter of a cutter for a 'special'.
Eventually that too was sold, strangely enough to another doctor, about two years ago. No doubt there will be time I guess when I may regret that but so far it hasn't occurred.
This is not to say they are not worth having or that they don't do a good job but just that like Jeff intimates they are not neccessary to be able to cut metal.
'Tis without doubt there are many very desirable 'bits of kit' very attractive to the model engineer - its down to paying money and taking choice in the end - but again I agree with Jeff perhaps much better spent on other items of more use.
Where I slightly disagree is in acquiring the skill to grind a tool. Like all things 'Practice makes ..... etc' and the more it's done the more experience is gained. Once an idea of the angles required are learnt for the various metals (and plastics) its easy enough to produce them by hand. One of the barriers often seen is to have to reduce a hefty lump of HSS to the shape required creating lots of heat, dust and sparks which is exactly how I saw it so long ago. When you consider just how small the area of a tool is doing the actual cutting  the size of (HSS) blank behind it isn't that important. As already said many of my tools are made from easily ground, totally free, FC3 cutter shanks fitted to steel holders. More than adequate for most tasks and especially for the fine finishing cuts so I guess I'm more than happy to be left out of the hunt on this one
On the basis of one pic etc,  with no offence grannies -

That said I'm a great believer in cat skinning and using each day to learn something so Ian SC's post on the saw blade carbide tipped tool is interesting. Is that brazed in Ian?
(Ian doesn't say but for those not certain carbide is usually ground using a much softer 'green grit' wheel before lapping)
Thread: Slow loading pages.
07/02/2010 14:19:16

Thanks Les, Two seconds eh? I wish.
I just have this sneaking feeling the cause lies within this box of tricks but I have no idea where to look.
I doubt it will sort itself so I guess it will have to go to the sick bay!
Thanks again - Ramon
07/02/2010 12:33:54
I have been having real problems with pages loading yesterday and today
Is this something I or the computer have now caused or has anyone else experiencing the same frustrating slowness - sometimes minutes from page to page.
Any comments would be appreciated.
Regards - Ramon
Thread: Nova 1 compression ignition engine
07/02/2010 12:21:45
Hi John,
Thank you for your kind words and posting. Yes I was very pleased but not half as much as my friend John who phoned on Friday to say that he couldn't get his to run. He brought it over and the cause turned out to be nothing more than a raher small prop (7 x 6) and some old fuel. A change of both brought it (and him!) to life and it too ran very well. Here's a pic of the two - it's now gone off to have a tank made and then we'll have a twin run.
This has proved to be an ideal i/c project. The drawings were excellent, it was easy to machine - even that crankcase. and it was relatively quick to build. I see 'Hemingway' are going to produce castings from the Roger Schroeder patterns later in the year and the Nova is among them.
Some of 'lifes circumstances' lead to a total lack of interest in machining about five/six years ago and though there has been the 'odd flicker' this project has done more than anything to resurect my passion for it. It's certainly fired me up to continue.
On that note I'm sorry to hear of your disappointment in not being able to get yours to run. What kind and type have you made? and when you say 'scratch' do you mean entirely to your own design or scratch building to anothers. My experience is limited to two stroke diesel and glow I'm afraid but normally, if it will fire but not run it's usually the fault of porting/timing anomalies and or fuel/air mixture problems. Lack of crankcase pressure is another cause. How about telling us more about what you have done to see if anything can be done to improve them.
Regarding your suggestion of writing it up. I am quite happy to have a go and did infact contact the editor to see if the images were suitable but have had no reply. I notice in ME that he has had computer problems so perhaps this is the reason - I will try once more.
Don't be apprehensive about retirement John, just get prepared! though it sounds like you are already thinking that way with your thoughts on that larger workshop. I'm sure you don't need telling but you should be prepared for the time over the next two years to disappear at the most alarming rate!!
Best Regards - Ramon

Edited By Ramon Wilson on 07/02/2010 12:25:03

Edited By Ramon Wilson on 07/02/2010 12:38:03

Thread: Knurling
04/02/2010 16:13:09
Hi John,
I'm sure you will find that this is a much easier operation if you set the knurls to the diameter to be knurled by using the hand nut to bring the knurls into contact with the workpiece, retract the tool off the diameter and then apply the (depth of ) 'cut' by turning the nut - small amount found in the first instance by trial - then starting the lathe and feeding the knurling tool gently but firmly back onto diameter. This puts the cut on gradually and you will feel it as it goes 'over center'  bring it back slightly and then apply sideways feed if required. If the pattern isn't deep enough, retract, apply another small amount and feed on gently again - the knurls will  pick up again providing the speed is kept low.
Originally I did as you describe - cramming the knurls takes quite some pressure - but once shown this way have never had a problem - much easier on machine and operator!
Hope this helps - Ramon
Thread: Boring Question
04/02/2010 13:02:24
Following the good advice and procedures from Merrick and Clive which is definitely the way to go about the operation (whatever type tooling is used) I would however agree  with Circlip regarding using HSS tool steel.
The problem with virtually all carbide insert tipped tools is that they are prone to rapid wear if not worked at their optimum rate. This normally leads to the final fine cuts being 'pushed off'' and nothing happening at all - especially if the material is a little prone to work hardening. This leads to the unwary (and sometimes the not so-definitely bought the tee shirt on this one!! ) putting on further 'one thou' cuts until - whoops - the tool digs in and takes the bore undersize. This can even happen with a brand new tip which becomes really frustrating.
They are of course 'attractive' aquisitions and do have excellent uses - roughing - especially cast iron and the tougher steels but I believe nothing will beat that well sharpened HSS tool for the finishing and/or sizing cuts.
Many years ago I made GHTs boring bar set and can thoroughly recommend it. Well worth the time spent. The bars use small pieces of inexpensive round HSS which are even more inexpensive if the shanks of worn FC3 cutters are used. - incidentally many of my lathe tools are made from these - the bits held in 1/2 x 3/8  gauge plate holders with a 4BA caphead. Quick to grind too.
The other thing made for boring was a set of 'between centres' boring bars - these are excellent for producing a parallel bore and eliminating the possiblity of 'push off' induced taper'. I have some pics if that will help anyone.
Hope this is of use - Ramon

Edited By Ramon Wilson on 04/02/2010 13:31:24

Thread: Knurling
03/02/2010 09:23:10
Hi Russell
It is much easier on the movement of the knurl if there is a slight lead-in angle but this does have the effect you describe if you cannot  move the knurls well past, but preferably not off, the edge of the knurling area. Ideally it is more practical to try to arrange this situation but of course that is not always possible.
Depending on the type of knurling tool an angle is beneficial, whether push or scissor type - the  rather long armed Jones and Shipman scissor tool for instance would flex sideways considerably, the cutting resistance bending the tool away from the direction of travel so having a lead angle helped overcome this to a degree  and prevent the opposite happening ie the leading edge digging in. This is less of a problem when reversing the pass as the knurl was already formed. Once the travel stops this tool would then 'pull' itself along the knurl a little for the extent of the movement in it's arms and due allowance would need to be allowed. Not good when it's rather close to the jaws! but if quick enough the lathe could be run in reverse to overcome this effect!!
If the problem you describe of a thinner pattern  was encountered the tool was pulled back, the angle reversed and the tool slowly engaged again picking up the knurl. Not ideal but acceptable.
There is also the possibilty of course of making the area to be knurled slightly wider and then machining the 'thin' area away afterwards.
As most of the previous postings show 'pressure' knurling is not exactly a science, it can at times be be rather hit and miss, even in a works environment. Though some advocate - and are successfull - in using higher speeds I have always found the lower speeds give a more controlled approach especially when starting the knurl the, higher speeds tending to produce a fine crossed pattern and the higher speeds definitely needing the ability to get the chips away quicker as well.
The one thing I'm fairly certain of is that this operation proves far more thought provoking than most, especially to the novice. Like many things it is best to practice on some scrap first and gain some experience rather than wait until that perfectly turned new part is ready for that 'experimental' op to finish!
Hope this helps -Ramon
02/02/2010 09:31:32

Just like to confirm that Tony and Zigfire have it spot on. Diameter isn't important just slow speed and feed and - if possible - lot's of coolant to clear the swarf. The small approach angle is very beneficial too especially on long knurling.
Like Tony lot's of knurling has been carried out however we always would set the knurl (scissor type) to the diameter first by closing the knurls to the workpiece then backing off, applying the depth (one/two flats on the top nut) winding the tool back onto the workpiece and checking for depth. This was a much gentler way than crushing the knurl into the diameter using the nut and gives a slower 'uptake' at the start of the knurl. If the depth needs increasing do this on a second pass.
Where possible knurling on a raised 'land' is much easier as well, kissing the edges with a 45 tool giving a nice finishing touch.
This is one op where the home machinist can struggle because of that coolant requirement, I know I do as my set up is very much a brush and jar one - I do have some very nice very short haired brushes though! A 'squeezy' bottle with a small spout to get a good jet is okay too just use as much as you can. I wouldn't recommend using the thicker high pressure cutting lubricants however because they tend to help the swarf stick in the knurls.
Keep on knurling
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