Myford Lever Action Tailstock Design and Build

Following on from this thread here LINK I am in the process of making both a 1929 sensitive drilling attachment plus my own copy of the original Myford ML7 lever action tailstock attachment. I am reverse engineering the latter from pics of the Myford original on the internet.

The plan so far: (Can you tell I once worked in the drawing office for three months?)

(Sorry once again about sideways image. Can't seem to fix it. Perhaps the mods once again could fix it, pleeeze?)

But I am short of a few critical dimensions. What I can't measure from screen pictures is the thickness of the link that goes between the tailstock body clamp and the main hand lever. I am guessing it would be a piece of flat bar about 3/4" x 1/4" (20mm x6mm) but not sure.

Also, I am unsure what size the pivot bolts in that link would be, and the third main pivot bolt that connects the hand lever to the tailstock quill clamp. I am guessing 5/16" but not sure. And are they just plain bolts, or are they shoulder bolts with a plain shank and smaller diameter thread?

If some kind person who has an original Myford lever attachment could measure the link's width and thickness and those bolts and let me know I would be forever in your debt. So far it is the only remaining stumbling block.

I have made a start already, digging a piece of 3/4" thick steel plate and similar alloy plate out of the scrap box and making up a couple of paper templates just as "proof of concept" so I know the material will be big enough. Turns out they are so have carried on making better drawings and laying out.

Both pieces are scabby old offcuts from the metal yard where they have cut these holes out of plate, hence the laser/plasma starting hole in each. The hex bar is to make the pivot bolts if they are not standard bolts.

Will be a bit of working cutting these out on my new horizontal bandsaw and doing the rest in the lathe as I have no mill. Happy days.

Edited By Hopper on 13/03/2022 11:00:21

Mod edit: rotated photo

Edited By SillyOldDuffer on 13/03/2022 11:03:04

Be patient, I will measure the one I have later today and get back to you. I will have it in front of me and will be able answer the question. The earlier ML7 is different from the later ML7 and Super 7 tailstock. Till later, Noel.

Thanks Noel. That sounds great.No rush. I am off to bed here shortly in Upside Down World. 

I think the Super 7 link and pivot bolts are somewhat similar dimension, from looking at a million pics on the net. This, below is the one I am copying. I am also trying to work out what sized square bar to use to make the handle. The square where it attaches to the link looks to be about 3/4" square to me, but again not sure. Of course I have half inch and one inch square in stock (the scrap box) but no 3/4"!

And is the round part of the handle 1/2" diameter?

I have thought about putting the Super 7 type offset handle on it but that may have to come later.

Top view showing the black link and the three mystery pivot bolts.

Also am I right in thinking the adjustable stop bolt at the front would be 1/4" diameter?

It's been easy enough working out all the larger dimensions by setting photos so the hole in the middle of the main clamp is the known 2-1/8" diameter and measuring off the screen. Easy enough for things like the length of the handle and the link etc but impossible to be sure on the smaller diameters etc.

Edited By Hopper on 13/03/2022 11:21:20

Edited By Hopper on 13/03/2022 11:24:55

Edited By Hopper on 13/03/2022 11:37:38

Just for interest there is a design for an ML7 lever feed tailstock in MEW 16 page 30 .

Dennis

Hi Hopper into Drummond Myford group we are having a few castings remade and tailstock lever feed is one of the products being 're-cast

https://groups.io/g/drummondlathe/topics?p=recentpostdate/sticky,,,20,2,0,89675718

Just thought it could be useful for you.

David

Thanks David. Very handy. Yes I think it would fit a Myford. The ML7 tailstock is 2-1/8" diameter where the clamp goes, and the Drummond is 2 -1/4". I have been a member of the group since Yahoo days but still have trouble navigating it to find specific things. I see a post by Rob Gough that castings are available and at a good price too.

But shipping to Australia has gone stupid since Covid. It's now 30 quid for a small item, and 60 quid and upwards for anything with a little weight, like castings. Plus there is now a 2 month backlog of parcels sitting in customs in Sydney. A parcel Myfords dispatched to me on Feb 7 got to Sydney Feb 9 and tracking now says it's in Customs and expected delivery date is April 7! So I have made a start on my fabricated version as I would like to be using it next week.

Are drawings available anywhere for the Drummond lever action? Could not see any in the .io group's Files section. And looked up Geoff Walker's article in MEW a year or three back but it was for a different type of lever action that keeps the handwheel in place, an ancient Ian Bradley design I think. It might be helpful if I could see the drawings just to double check what I have surmised from looking at pictures.

Shame about the postage. I really would like a set of those castings and the apron mod ones too.

Regarding the pivots, they should be of smooth finish on the bearing surface, and a good running fit in the holes.

So a standard bolt (i.e. with a plain shank between thread and head) may suffice if the shank is of appropriate length, roundness and finish quality. For a decent result though, it is better to make to suit.

I have made a bit of progress since yesterday's post.

Marked out the quill clamp, bandsawed the circle of ally roughly square so I could grip it in the chuck and screwcut the 1" LH Acme thread to clamp on to the quill. Good thing I centre popped the outline as the blue marker pen does not stand up to heat or swarf at all.

Came up good though. Screws right on the quill like a bought 'un.

So not being willing to pay $50 (25 Quid) for a small spray can of Dykem layout blue, I used "marking red" on the tailstock body clamp. Aka a bit of leftover spray can paint. Marked it all up in the traditional manner with a sheet of plate glass and marking gauge plus the usual dividers, square etc. The only problem with the paint is if you make a mistake, as I did of course, you can't just quickly paint over it and carry on!

Set it on the faceplate on parallels all done on the bench so the parallels don't slip out all time and cause bad words to be uttered. And found a super easy way to make sure the job is set up well centred before mounting the whole thing on the lathe. A pair of jenny leg (hermaphrodite) calipers measuring from four points around the perimeter soon got it dead nuts on.

Well, within six thou or so anyway. Two little taps wiith a brass bar and it really was dead nuts on. Not that it's particularly critical in this instance, just whiling away some pleasant time.

Edited By Hopper on 14/03/2022 10:38:31

Thanks Nigel. Following a message from another member, I am looking at making my own shoulder bolts with 5/16" plain shanks and 1/4" threads on the end. Will ream the holes to suit. Unless I find out the original Myfords did differently. Will be a while before I get to that stage so will wait and see what Noel measures on his original unit.

And spent a boring afternoon.

This was when I wished I had a lever tailstock. Punching a 1' drill through after a 1/2" pilot.

And the boring bit: opening the drilled 1" hole out to 2-1/8" with repeated 70 thou deep cuts. Any more than that and the whole thing carried on like a pork chop.

And an excuse to use my latest garage sale treasure, an M&W 0 to 4" micrometer, still in its original box. Used with a telescopic T gauge it got the hole spot on. The tailstock boss slid right in as if it were designed to do that. Good measuring tools are so nice to have.

So that's the easy part done, the two round empty spaces in the middle. Now on to the tedious bandsawing and grinding and linishing of the complicated outside shapes. (Wish I had a set of those castings!!!)

Edited By Hopper on 14/03/2022 11:02:04

Edited By Hopper on 14/03/2022 11:02:31

Thanks Dennis. I checked that out. It uses Heim joints for the pivots, which is probably a smarter more modern way of doing it. But I decided to keep mine traditional looking to fit in with my other antique machinery in Hoppers House of Heritage Horrors. Plus it looked to me like the Heim joints would let the handle wobble up and down loosely as the Heim joints move sideways as well as radially. Not sure about that. But it did give me some useful measurements re handle length etc.

It's unnecessary to screw cut the clamp, all that is needed is a good fit to the threaded section - per my original Myford ML7 lever feed tailstock which is still in the workshop. The clamping screw does the rest.

Robert Butler

Edited By Robert Butler on 14/03/2022 13:10:17

Beat me to it Robert the original Myford one was just a well fitting plain bore and pinch bolt

I think there are several versions of the original that i saw pics of. Some seem to have the thread and some not. Certainly good production engineering to eliminate it. Being a belt and braces kinda guy though i decided to screwcut it to be sure -- and largely just for the sake of amusement cutting a LH Acme thread.

I have the exact same 4 inch micrometer here, picked up at a club auction more than 20 years ago. A really useful bit of kit. It is complete with all the little spanners and calibration pieces too.

I've just come inside from a similar piece of work on the lathe, but the hole I needed was 75mm in a funny triangular shaped piece of inch thick alloy. I had to reverse rwo jaws of the four jaw chuck to get it into the Myford.

My Myford has a lever action tailstock, made by my late father using a rack and pinion out of a small car.

regards

John

Now that is a brilliant idea. I'd love to see a photo of it if you have one.

Hopper

A bit of progress today. Rough cut the outline on my new horizontal bandsaw, just making straight cuts with the job held in the vice with the saw in horizontal mode. And drilled and tapped the 1/4 BSW holes for the clamp bolt and depth stop bolt. Have not yet decided on what size to make the main pivot bolt that screws in the top of the this bracket.

Looks pretty 'orrible at the moment but an hour or less to finish it off on the belt sander and linishing wheel attachment on my 8" grinder will have it looking like a "proper" casting.

Hi Hopper, The lever is 9/16 dia 12"long + 1/2" for thread, can't unscew Knob that is 1.25" dia. The link is 3"long, 3/4" wide and 1/4" thick 2 holes 2.25" apart, 7/16 dia. Pivot bolt 1.385" long over all, head .6"AF, .2" Deep,pin 7/16"dia .715" long and thread 5/16" BSF.470" long., 2 OFF The 3rd pivot bolt is like the others but the pin is .7" long and thread slightly shorter.at .375" The depth stop is 3" long, 5/16" dia with a .040" deep flat milled on. pinch bolt is 1/4"BSF x .5 long. These dimentions are from a unit for a Super 7. Just looked at you last pic My unit has no thread in, the lug on the bit that goes on the tailstock is drilled 5/16" with a pinch bolt and flatted rod.  If you need more then get back to me. Best wishes Noel.

Edited By noel shelley on 15/03/2022 17:46:15

Thanks Noel. That's brilliant. Very comprehensive and helpful with all the details. Will keep you posted how it all goes.

And I just realised perhaps why Myford did away with the Acme thread in the quill clamp on the later models. It would be easier to take on and off by just sliding over the thread and doing up the pinch bolt. I will have to faff about unscrewing the clamp off the quill thead. So after all that good work I may end up boring it out smooth anyway! Oh well, it's all very much a work in progress and keeps me out of the pub.