Here is a list of all the postings Chris Crew has made in our forums. Click on a thread name to jump to the thread.
|Thread: Quick change tool post and parting tool for a lathe|
For parting I would highly recommend that you either make or acquire a suitable rear tool post. I am not familiar with the Boxford B or whether Boxford's ever produced a rear tool-post for it but they are easy enough to fabricate. You may find that mounting a parting tool in a front mounted quick-change tool holder may not give you a sufficiently rigid tool-holder as parting-off produces all sorts of problems, especially for a beginner with dig-ins and tool breakages etc. IMO you must always use copious amounts of cutting lubricant/coolant to assist successful parting. There is another thread somewhere on this Forum all about parting because we have just had a debate on it ad-nauseam so I won't begin to repeat the advice here.
Edited By Chris Crew on 26/04/2021 20:20:21
|Thread: Calling all Colchester Bantam owners.|
I have a metric Bantam 2000. The only advice I can offer is to take a degree in Crypton Factor to allow you to figure out the screw-cutting gearbox. It just about makes sense when you get there but I suggest you add your own notes in the manual because it covers all variants of the gearbox which are very easily confused until you become really familiar with it.
PS. I can send you a scanned copy of the relevant pages of the manual with my annotations if you contact me through the messaging facility on this forum.
Edited By Chris Crew on 26/04/2021 07:55:45
|Thread: Faster Screw-Cutting|
May I just add, because 'ega' has mentioned the Radford quick-change tooling system on the tool-post shown in one of the photographs, that I made this accessory and found it to be the veritable answer to a maiden's prayer as my late colleague also used to say.
It worked so well and is so very convenient to use that I went on to make sixteen tool-holders for it and I have actually been meaning to make half a dozen more. It very rarely leaves the Myford and, in my personal opinion, it is far superior to anything that is available commercially if carefully made with the jigs that Radford also describes. It holds the tools securely and repeatably at centre-height and can be made for next to no outlay compared to the prices of commercially available models. I can't recommend it highly enough!
BTW, I am very grateful for all the responses so far received which I have found both interesting and informative.
Edited By Chris Crew on 24/04/2021 13:44:35
I am fortunate enough to have an Ainjest rapid threading attachment fitted to my Colchester Student lathe which makes screw-cutting as easy as feeding buns to elephants, as a dear old colleague of mine used to say. Being an admirer of the late Jack Radford, I have recently been considering making his Six-Position Saddle Stop for my Myford ML7-R which works in a similar way but disengages the lathe's own half-nuts, rather than an auxiliary half-nut as on the Ainjest.
Could I enquire as to whether anyone has made and used this particular attachment and how effective it is? The design calls for a modification to be made on the apron and I don't particularly want to 'butcher' the machine if the overall end result turns out to be hardly worth the effort. Radford himself admits that there is small delay in the tripping of the mechanism equating to about 0.125" of saddle travel but I think this could be eliminated in practice when setting up for arresting the movement as with the Ainjest. Something in the back of my mind tells me that Martin Cleeve also designed a similar 'gizmo'.
|Thread: Myford 254 Plus toolpost type|
Personally, having made one years ago for an ML7-R, I think the GHT rear parting tool-post is awful. As with all GHT designs, it is 'flimsy'', difficult to adjust to the correct working height both in construction and use because of the angled blades and not particularly aesthetically pleasing either. Having been mightily disappointed by it after a week's worth of construction time, not to mention the cost of the castings etc., which were then supplied by Reeves, I bought an OEM Myford rear tool-post and found it to be very satisfactory, although I don't use the 'boat' to adjust tool height. For my Student I fabricated, as near as I could get to the OEM design, the Colchester rear tool-post and I have easily parted 6" noggins of mild steel for Myford back-plates and gear blanks with it, so perhaps making a cross between the two types would suit the 254, although I am not familiar with this lathe.
|Thread: Gear Change Wheels for a Smart & Brown Model A lathe|
Probably not so important when just cutting 5TPI with a 6TPI lead-screw, but the advice when cutting threads coarser than the lead-screw is to drive the head-stock from the lead-screw, rather than driving the lead-screw from the head-stock, although I would take a few more lighter cuts just in case.
I do this when cutting multi-start worms or even a worm of a larger DP to relieve the stress on the change-wheels. I am not mathematically or technically competent enough to calculate the actual stress on the gear teeth or at which point they would fail, but I take the advice given by Cleeve and Law et. al. for doing this.
It is no great pain to wind the lead-screw by the hand-wheel when cutting relatively short threads or worms but it could be if the thread is longer. I have jury-rigged up a reversible motor, reduction box and sprocket drive to the lead-screw of an ML7-R because you obviously cannot dis-engage the clasp nuts when cutting pitches that do not contain factors of the lead-screw thread.
|Thread: Starting out a young enthusiast|
I suspect that the teachers at the school I attended in the early 1960's didn't have the best interests of their pupils at the forefront of their minds. I would hope that things are very different now.
Edited By Chris Crew on 30/03/2021 22:35:59
Edited By Chris Crew on 30/03/2021 23:13:38
Well, I suppose on one level that makes sense but we are not really supposed to wire 13amp plugs these days, that is why all new appliances now come with a moulded plug attached. I know we all do have to do it from time to time and hopefully the majority of us do it competently but I would put money on it that there will be some horror stories out there caused, for instance, by poor colour vision. An appliance will still work with the earth and neutral reversed because the neutral is earthed at the sub-station but any imbalance in the distribution could produce potentially fatal currents that could not be dissipated.
The domestic wiring regulations preclude any unqualified person, as I understand it, from doing much electrical work within our own properties, save perhaps taking a spur off a ring main or wiring a lamp. There two ways of looking at this. I am not a 'qualified' electrician, whatever that is supposed to mean but I have worked on and around electrical installations for most of my life, from 50V DC very high current equipment through to 415V AC three-phase distributions and consider myself more than well 'qualified' to undertake most installation tasks to the highest standard, although I could not 'certify' the work as being 'safe'. However, what may still be termed Part P regulations prevent me from doing much in my domestic environment unless I had the work independently tested and certificated.
I have to say that I probably agree with all the restrictions because, although I consider my workshop to be cabled and wired to a very high standard with an auxiliary consumer unit for double protection and all conductors contained in trunking and conduit etc. (all done prior to Part P so perfectly legitimate) I have visited some workshops that appear to be no more than electrical accidents waiting to happen. And this by men who I have considered way above me skill-wise. Bits of cable either twisted together and wrapped in insulation tape or strip connectors hanging over machines etc. or trailing extension sockets all over the place. Just for the sake of a few pounds being spent on doing the job properly and safely.
I know this could be a controversial subject for those who consider their workshop environment sacrosanct.
Edited By Chris Crew on 30/03/2021 20:11:43
|Thread: Vehi cle Tax Scam|
I haven't had this particular scam email yet, and I don't know if this happens for everybody and every type of vehicle, but DVLA always sends us a reminder in the post when the road tax is due on both mine and my wife's car with a reference number to pay online.
My problem is that the wife always passes hers on to me!
|Thread: Excellent Chinese Chuck|
Whilst undertaking a certain task I began to muse how much easier it would have been if I only had a 4-jaw self-centring chuck for my Colchester Student. At a lose end, and purely out of curiosity, I started to search online for one expecting it to be way out of my price range when a new 8" (200mm) chuck came up for £108! Nah!, it's got to be a scam, someone's hacked an eBay advertiser, I have had it before when looking for a Makita drill. The make was San Ou so obviously Chinese. I had never heard of them before but started searching for reports and reviews and looked at the company website. Not much to be found really, some debate in this very forum a couple of years ago and a YouTube video of somebody in the USA having to correct an in-accuracy in a 4-jaw independent he had purchased. The reviews were around 50/50 either way to be fair, but in any event you don't get an 8" 4-jaw self centring chuck for £108 delivered do you? Of course you don't!
But something kept eating at me to call the scammer's bluff. PayPal and eBay had protected me well enough over the Makita drill hadn't they? And whilst no one wants to be conned out of over £100, even if I lost it I would not starve to death and it would just prove to myself what a fool I really was for allowing myself to be duped. So I took the plunge and clicked the 'Buy it Now' button. The order and Paypal receipt emails duly arrived indicating that the item and delivery from within the UK actually cost £90 plus £18 VAT. Expecting an email from eBay or PayPal withdrawing the purchase because it was not genuine I was astounded when another email arrived later in the day indicating that the item had been dispatched and supplied a Yodel tracking number. What? Is this genuine after all? Apparently it was.
Imagine my surprise when a package that I could hardly lift arrived by courier within three working days of placing the order. OK, so what's inside? Err..... this actually looks like a decent piece of kit, complete with a set of outside jaws, a substantial chuck-key and mounting screws, it will need a suitable back-plate of course but I'll worry about that later. For now, let's just put it on the bench, take it apart and look for all the faulty manufacturing that some people keep telling me is a sure sign of cheap Chinese crap which is an utter waste of money. Well now, everything looks to have a nicely ground finish, there doesn't appear to be any slop in the jaws so let's take it apart and look at the scroll It's got to be bad even though it does feel quite smooth when un-winding the jaws, the Sino-phobes have got to be right sometimes, haven't they? Jaws out, back removed, scroll pinions out which looked to have close fitting finely ground journals and the gear of the scroll looked nicely cut, plus there was no slop on the hub on which it mounts. Scroll out and quite unbelievably it looks very nicely machined indeed. So let's clean everything in petrol, lubricate it with H32 and put it all back together.
Now let's find a back-plate. Good Grief! An L.0 fitting is going to cost almost double the chuck from the usual suppliers. Ebay to the rescue again when I won an auction with fifty quid for a fitting that would require an interstitial plate making but would fill the bill. Made a suitable plate and turned everything true in the lathe in which it was to be used including a close fitting register for the chuck taking a great deal of trouble along the way. Mounted the chuck and put a ground 0.625" bar in it to be clocked for concentricity. Moment of truth, this thing's going to be way out just like that guy's in the US and a bit of tool-post grinding will be required to true it up. But wait, should I have gone to Spec-savers or is that clock needle really only moving 0.75 thou. near the chuck jaws with the lathe running slowly. Move the clock a bit further along the test bar and let's see that needle really start to swing. No, it moves about 1.5 thou. 12" out from the jaws. That'll do, as they say in Yorkshire!
Delighted? Jumping for joy more like! I still cannot believe I only paid £108 for this obviously well made and accurate piece of kit and just proves that price isn't a measure of quality.
|Thread: What Did You Do Today 2021|
I spent the day on the hacksaw chopping an 8" long piece from an 8" x 20mm steel bar and then making the resulting square approximately round as the basis for an interstitial plate between a Colchester L.0 lathe mounting and a cheap Chinese chuck. It took most of the day, off and on. I then spent the next hour rubbing Voltarol into my right shoulder!
Edited By Chris Crew on 26/03/2021 23:32:51
|Thread: Griptru chucks|
Personally I wouldn't bother with the expense of a Grip-tru. It is standard practise to do as much as possible on a work-piece in the lathe at one setting, and if possible finish it completely before removing it from the chuck or before parting off. I have removed chucks from the Myford with the work-piece still in situ and remounted the chuck on a Vertex dividing head on the mill for milling flats or key-ways etc. before putting the chuck back on the lathe for a final operation or parting off. It's been accurate enough for what I have ever needed to do in a back-shed workshop but it's only been possible because the Myford nose is replicated on the dividing head. This may not be the case with other combinations of lathe and attachments. There's a way round everything if you just stop and think for while. Just because you are a beginner doesn't make you stupid and your common sense and logic is just as good as anyone else's.
|Thread: New Member wants to make a purchase from the classified section...|
I would have thought that if you bought the magazine the contact details of a vendor would be in the classified ad.? Sellers don't usually hide from potential buyers or am I mis-understanding something?
|Thread: A home-made gear - will it work?|
The angle of the teeth will equal the helix angle of the thread. The imperial Student has a 6 TPI lead-screw, mine has anyway but I don't know about that on a metric lathe. You may have to vary the involute cutter number when cutting what is in actual fact a short slice of a spiral to mesh with the lead-screw because the helix angle makes the tooth slightly wider which changes the involute although I doubt if it matters in this instance as the gear is small and not transmitting any power. All this information is contained in Ivan Law's Gears & Gear Cutting book. Law recommends that you cut a tooth space in one pass rather than nibbling away at it, although you may have to gash it if your machine is not robust enough to take a tooth space out in one go. As you have the original gear to copy you are almost over halfway there, count the number of teeth, calculate the gear blank if you know the DP and set up an appropriate cutter over the blank in the dividing head. I don't know the included angle of the Student lead-screw thread but it will equal to a spiral rack so you may have to approximate the pressure angle of the gear, 14.5 or 20 deg. whichever is the closer.
I can't claim to be any expert on the subject or that I have cut a great number of gears and racks but those I have cut over the years seem to function well enough for the purpose they were intended to serve in a back shed workshop, although I have no way of measuring their final accuracy. If you wanted to cut the splines for the boss, you can do this in the lathe with either a slotting attachment or simply mounting a suitable tool in the tool-post and working the saddle back and forth, provided that you have a method of indexing the lathe spindle. Again, I have cut splines using both methods successfully enough for my amateur purposes.
Edited By Chris Crew on 24/03/2021 00:08:46
Edited By Chris Crew on 24/03/2021 00:14:11
Edited By Chris Crew on 24/03/2021 00:18:13
|Thread: Home Made Rear Toolpost Issue|
For my two-pennyworth, mild steel does for most jobs probably simply because I acquired a mountain of the stuff when my erstwhile employer closed its tool room and workshop a few years ago and it is very easy to work with. I have made most things out of it even where other materials have been specified. Of course, it would not do in industry or a professional environment, but in the home workshop where sliding or rotating parts are not in use eight hours a day, five days a week, it is very unlikely that it will ever wear beyond use. The only things that I use higher quality hardening steel on are, obviously, home-made cutting tools. The Colchester rear tool-post I copied is made out of mild steel and works fine for me.
I am sorry that you have suffered this failure, but please don't give up because (only speaking for myself) we all have disasters and learn from them. Also, you are not alone in having to make things fit, it's part of my workshop activities and consider myself lucky that I have the necessary equipment and a little bit of skill to be able to do this. If you are not prepared to splash out on a OEM Myford rear tool post I would suggest that, unless someone has another type to sell you or Ebay is not forthcoming, then your only alternative is to make one. I would copy the Myford myself because, although I am a great admirer of GHT as a mentor and guide, I am not so enamoured of his designs which always seem to me to be lightweight and lacking substance. And before anyone takes a shot, I am not setting myself up as knowing more than the great man himself. It is just that as he was such a superb craftsman I always imagine that his tools were always super sharp and so perfectly honed that they needed very little force to effect a cut. A state of perfection I have never been able, and never will be able, to achieve!
You can copy the the ML7 rear tool-post easily enough, I copied a Colchester rear tool-post out of noggins of mild steel and it works perfectly well for me. In fact if you are anywhere near the middle of Lincolnshire I have more than a lifetime's supply of suitable noggins and you are very welcome to collect one. One thing I would say, again only as a personal opinion through experience and not withstanding the crack in your tool-post, is that if something is going to hold and grip securely, it will do so with not much more than a 'nipping-up' and will not require any excessive heaving on a spanner or allen key. How many tee-slots will have been broken out by excessive tightening by people thinking that this will stop a work-piece or tool shifting? A soft card gasket usually cures a tendency to shift under most cutting forces but if it doesn't you should be looking at other ways to secure a tool or work-piece.
Edited By Chris Crew on 07/03/2021 18:45:17
|Thread: Chinese End Mill Grinders|
Thank you all for your views. I am not really tempted to buy one of these machines as I have a Clarkson Mk 1 and I am over halfway through building a Quorn (if it ever gets finished!). It was just that I was not aware that this type of machine existed or whether it was available in the UK. But can I say just for the record that I do not 'adore' Chinese made products and I don't believe for one moment that the wiring would kill me simply because all imported products have to be of a certain standard. Before Brexit products were marked and tested to CE standards and now they will be marked and tested to UKCA standards. All I have stated in other posts regarding the majority of Chinese products is that I have found that they always work first time out of the box and do the job they are designed to do at the price point in the market they are intended to serve..
Every product is built to a price and market entry point including the Clarkson/March machine, and other no longer available British machine tools and accessories, which if viewed from a super-critical standpoint would all leave attributes to be desired. The Clarkson, for example, relies almost entirely on the judgement, estimation and skill of the operator to obtain satisfactory results. Maybe a lot of us would like to have a £1,000 Jones and Shipman rotary table or tilting/swivelling vice, which I doubt are even manufactured these days, but we have to either settle for the imported versions, which do exactly the same job, on the grounds of both availability and price or go without.
I know it rankles with some people that Britain is no longer a leading manufacturer of the products we need to buy and are looking for reasons to decry imported goods, often unfairly in my view. I can almost understand that because the British manufacturer that I worked for was put out of business by the Chinese competition in 2005 and I lost my job, so I too have every reason to feel aggrieved. But that doesn't make the standard of the Chinese product unacceptable per se, or the British product inferior. It just means that the customer declined to pay the price of the British product when offered an alternative which is what, I imagine, happened to Myford at Beeston, Tom Senior at Liversedge and other engineering manufacturers who either disappeared altogether or moved into other markets like Boxford or Denford where they stood a chance of survival.
Notwithstanding the above, I am very grateful to everyone who has taken the trouble to respond and offer their advice which is respected.
Edited By Chris Crew on 06/03/2021 00:02:19
I found this company and its products by chance. These look very interesting and useful machines. Does anybody have any knowledge of their price and availability in the UK? I suspect there will be those just waiting to condemn them as just more 'Chinese rubbish', but I would possibly be interested in acquiring one if it is within a reasonable price range, which most Chinese machines seem to be.
The video is in Chinese so I have no idea what the guy is saying or what advice as to use he is giving and no idea how the machine may work. Take a look and see what you think.
This is the company:-
This is the video:-
There will be other pages to find along these lines and it will be interesting to hear what others think. These machines are new to me but others may know about them already.
Edited By Chris Crew on 04/03/2021 19:50:08
|Thread: Home Made Rear Toolpost Issue|
It isn't junk and it should work fine by the look of it. Have confidence once it starts cutting and keep it cutting with a goodly amount of coolant/lubricant on steel. The speed should not be so slow that it 'grates' and not so fast as to make it 'scream'. Keep pulling the blade into the cut with a steady even pressure once you start. The cutting should 'hiss' just like on any other turning job. In my opinion the tip of the blade should be set a tad above centre height, but that's up to you as some people don't agree. Welcome to the Happy Parters' Club!
(PS. I use the cheapest soluble oil I can buy from the local oil merchant and dilute it 20:1 with the water added to the oil and a dash of Rocol anti-bacterial treatment. If you buy a 5L container of oil for about £20 you will almost have a lifetime's supply. It works for me, I can't speak for anyone else)
Edited By Chris Crew on 03/03/2021 02:49:45
|Thread: 2-Part Covid Vaccinations|
I am dreading the lifting of the lock-down. It's going to mean meeting other people again and having to try to appear sociable and affable. Dammit!
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