Member postings for Hopper

Are you conventional milling, against the direction of rotation of the cutter, or climb milling in the same direction as the rotation?

Do you have all slideways locked except the one needed to allow the motion of feed?

What size cutters are you using?

The tests as you describe them are not telling you anything much about the lathe. Runout of a 6mm milling cutter held in the chuck is maybe telling you the chuck has about the normal acceptable runout for a three jaw chuck, or that the milling cutter is not perfectly straight, or that it was not gripped very well in the chuck. Plus, the condition of the chuck is not the condition of the lathe.

The other test of a dial indicator on the compound slide bearing on the bed as you traverse the carriage is telling you nothing. The carriage will follow the bed regardless.

Your metal cutting test sounds about right. You will get heat, and smoke if there is oil there, when taking a 1mm cut with carbide. Taper on a roughing cut like that means nothing.

There is nothing to be gained by trying to turn a longer half-metre piece of bar. The taper on it depends entirely on the tailstsock, which is fully adjustable. Turning test for taper without a tailstock centre is usually done with a piece of steel 25mm diameter and sticking out of the chuck by 100mm. Any longer and you get too much flex in the workpiece.

Once you get the lathe into your workshop, you can set it up with shims under the mounting "feet" to make it turn parallel without a tailstock centre, and then you can adjust the tailstock so it turns parallel with a tailstock centre in place.

It looks like a good quality machine, so if it is not making bad noises and if it is turning nicely like in your picture, I would buy it.

Edited By Hopper on 14/02/2023 02:59:13

It is in his book "Improvements and Accessories for your Lathe" which is still available.

Well, if it is just for that kind of small stuff on a mini lathe, a tailstock turret combined with a lever tailstock mechanism might be the easiest and cheapest option. You don't get the auto rotation/indexing like the proper turret in the video but for short run production jobs it would work OK.

There have been a number of designs for tailstock turrets over the years. From memory LH Sparey has one in his book The Amateurs Lathe" with drawings.  And ISTR there have been more recent designs in MEW. Plus of course these days you can buy them ready made.

Edited By Hopper on 13/02/2023 13:15:49

What is it that you want to make on your capstan lathe, and in what quantity?

There may be other, better or easier, ways of doing it if more details can be given.

As others have said, capstan attachments can be somewhat limited in their abilities and are not the same thing as a full-on turret lathe. So again, it depends on what you want to make and how many.

Edited By Hopper on 13/02/2023 11:58:13

The lever looks like it interfaces with that pin sticking out the back of the handwheel/dial assembly. What does that pin do?

It appears to have a separate feed shaft separate from the leadscrew, which is a sign of a better quality machine, not a budget special.

For me, that feature is an added benefit. What I wanted when I bought one -- cheap as chips on the net -- was an on/off switch plus the large red emergency stop button. Seems the best and cheapest option available to get this is the very inexpensive NVRs that are everywhere because they have become the industrial standard. If I get a power cut in my one-man workshop, I can remember to switch the lathe off manually so don't really need an industrial NVR but that is the cheapest and easiest way to do it. And it is an added safety feature and that never hurts.

I like the idea of having a second switch in case of emergency, or sometimes in case of flying hot swarf that you have to reach through to reach the reversing switch at the headstock end. An on/off or NVR switch with its big red button at the tailstock end can be very handy and means that hands and face etc are all well away from the working parts when starting up or stopping. So, maybe not a necessity but nice to have.

I have to say though, the more i look at that OP pic, the more showroom perfect that lathe looks. Beautiful.

Looks very nice indeed, like it has hardly been used. The leadscrew dog clutch is a very handy feature that is sadly missing on the ML7s.

The trick to turning larger diameter jobs on these is to use a fixed steady on the larger job sticking out of the chuck.

My ML7 has only the reversing switch, which has been on there for decades unknown without contact problems. I will get around to fitting an NVR at the other end of the bench at some point. I have had it sitting under the bench for a couple of years now, just needs wiring in. Nice to have two options for stopping and starting.

For a 0.3mm wide groove, you might consider using a piece of HSS hacksaw blade ground into a parting tool shape. There was a thread on here somewhere recently that showed a few examples, I think. Pieces out of a very thin HSS circular saw blade or slitting saw could be used too.

Lathe toolbits in hobby grade HSS are not really very good at being ground down that thin. They tend to crumble away as you have found.

Yes very sad. Those are some legendary races that have gone on for generations.

Just the latest example of the insurance companies running our society. It is not society that is risk averse -- people still want to go and watch the races -- is the insurance companies wanting to maximise profit by not covering anything that might remotely result in a payout.

Expect it to get worse this next year as the stockmarket continues to not do so well. That is where the insurance companies make much of their profit, by investing their huge premiums pool in the stockmarket and banking the returns. Somebody has to pay in a bad year, so of course it is us punters, with higher premiums and the refusal of coverage for anything remotely likely to result in a payout.

And behind that I suppose we can blame our increasingly litigious society and the resulting lawyers' picnics.

Edited By Hopper on 10/02/2023 12:02:25

Diogenes, I like your simplified version with the hacksaw slot instead of a separate moving piece. Very clever in its simplicity.

It;s not the overheating that is the problem, it is the dunking it in cold water while it is overheated that causes microcracks and a brittle cutting edge that does not last well. Braze away and let it cool naturally and all will be well.

If it is still taking you forever to grind a tool bit, it may be substandard cheap grinding wheels. They are about on budget grinders. Or you may have lucked out and got a piece of extremely high quality HSS with extra additives. I have some old pieces of Swedish HSS that take forever to grind, like trying to grind hardened glass or something. But once done they hold an edge beautifully. Try different bits of HSS and if that does not help, try some new good quality grinding wheels. But it is much much quicker to use 1/4" HSS and sit it on a piece of 1/8' packing in the tool holder. That is what I have gone over to doing on my Myford when I use HSS, purely because of the quicker sharpening.

You seem to have missed the point. Dunk the tool bit in water to cool it off. Just don't let the tool bit get hot enough to turn blue before you dunk it. So frequent dunkings and keep the tool bit cool. That is the quickest way to do it, the way it is done on professional shop floors.

If you want confirmation of this common and well proven method, see LH Sparey's book The Amateur's Lathe, page 75.

How long should it take to grind a 3/8" tool bit? For a standard turning tool shape such as a knife tool, five minutes or so. Maybe 10 at the most. The end of the blank comes already angled, so you only need to about 15 degrees angle to the top and leading side surfaces, plus about 10 degrees clearance on the end surface. It should not take too long at all.

This is assuming a six inch bench grinder with 1" wide wheels, well dressed and a good tin of water for frequent dunking. Rough it out on the coarse wheel first then finish on the fine wheel. Then spend a few extra minutes rubbing it on a bench oil stone to get a nice smooth cutting edge and to put a small radius on the tip.

Indeed! Truck axles used to be the "go to" for tough stuff. No idea what they were made of. Nobody knew. It just worked. Burt Munro even carved con-rods out of truck axles for "The World's Fastest Indian".

Thanks Noel. I did the old "faux casting" trick again to keep it looking original.

The lathe is painted in machinery paint mixed to paint code RAL 7011, "Iron Grey". It is actually a shade darker than the original Myford paint.

I think I painted that stop in rattle can Dulux colour "Machinery Grey" which is a tad lighter and closer to Myford original colour but not anywhere as near durable. So close in colour nobody really notices though.

The RAL 7011 is in real life a tad darker than it appears in these pics. The picture of the stop sitting on teh wooden bench top is closest to reality. Depends on lighting and computer screen calibration etc. But compared with the original-paint Myford dividing head and vertical slide I recently restored, the 7011 is definitely a bit darker, despite claims on various websites to the contrary.

I can't import Paragon paint etc due to hazardous freight regs etc so this is as close as it gets. But its a piece of workshop equipment, not a Rolls Royce Phaeton!

Edited By Hopper on 09/02/2023 11:01:44

Edited By Hopper on 09/02/2023 11:03:03

I remember sometime the past five years or so there was a two-part article about HSS in MEW written by a metallurgist. His advice was to never dunk your HSS in water when sharpening it but instead put the toolbit down and let it cool off slowly in the air. He was quite adamant about that.

On the shop floor of course, there is not time to stand around for five or ten minutes waiting for the tool bit to cool down every time it gets a bit warm to hold. So the workaround is to keep dunking the HSS toolbit in water frequently, BEFORE it starts to turn colour on the edges, in this way stopping the HSS from getting hot in the first place and doing away with the need to let it stand and cool off in the air for extended periods.

I don't remember if the MEW metallurgist's concern was micro-cracking or heat treatment issues, but the don't-let-it-get- too-hot-and-dunk-it-in-water regime is in line with what I was taught as an apprentice both on the shop floor by crusty old craftsmen who could machine new hinges for the gates of Hell if need be, and at tech college out of a book written by experts in classes taught by crusty old craftsmen who had gone on to get engineering degrees. Both agreed on dunking the HSS in water frequently before it turned colour on the edges so it never got overly hot.

Edited By Hopper on 09/02/2023 10:43:21

Edited By Hopper on 09/02/2023 10:47:21

Don't use phosphor bronze for halfnuts or leadscrew nuts. The original manufacturer used brass for a reason. It is so the brass wears, and not the leadscrew. A worn nut will faithfully follow an unworn leadscrew thread with unerring accuracy, just a bit of backlash that can easily be accounted for. But a worn leadscrew will never be accurate. Phosphor bronze will wear an unhardened shaft or screw. And most machine tools do not have hardened leadscrews or feed screws. Hence the use of brass or even softer Mazak for such nuts as original equipment.