Drummond type M tailstock alignment

Hi. I've been using a Drummond type m for a few years and managed some decent work on it with various materials. However one thing that keeps bothering me is the tailstock seems to keep going out of alignment. I notice it when centre drilling so I align it back up and it's spot on for a while and then after a few days I notice it's drifted again. Usually somewhere in the region of .005" to .010" out.

Is this a common issue on these? Or am I just doing something stupid? I do have a bit of bed wear on my lathe in the usual place, but I always set up the alignment of the tailstock in the position I intend to be using it for the current job.

Any input welcome, including ramblings.

Thanks!

Dan

I've never had any problem like that in many years of using my M-Type Drummond. I set it once years ago and have not touched it since, and it still turns nice and parallel. So something must be wrong.

It's so long since I did mine I don't remember the details but there is a locking bolt/s that you must tighten up after you make the side to side adjustment with the two jacking screws on the sides of the upper half of the tailstock body. If it is left loose, the adjustment can move out in use.

The other place to look is where the tailstock base sits on the bed. There is an angled gib block at the front that must be adjusted so it bears closely on the angled shear of the bed all the way along. If there is slack there, the whole tailstock can move around as it is slid back and forth.

Yet another thing could be the quill is moving when you tighten up the quill clamp, indicating the quill or the hole in the tailstock it runs in is worn. Easily checked with a dial indicator on the quill sticking out a bit and tighten the clamp and see if it moves.

Edited By Hopper on 18/06/2022 13:23:27

I've never done much that needs better than 0.1mm to 0.2mm of tailstock accuracy in my old jalopy

I would reckon that you will just have to keep checking regularly if its important because there will always be potential gremlins, MT1 imperfections, tailstock barrel issues etc

If I was doing regular 1mm holes I'd probably use something like a Cowells

Edited By Ady1 on 18/06/2022 14:30:03

Hi Daniel you should be able to repeat the alignment of your tailstock unless as it is not adjusted correctly or you have significant wear. I set my tailstock by mounting a lever type dial indicator in the chuck on a bar so it can be rotated and adjust till I get s zero reading, top to bottom and side to side.

I then clamp and unclamp and repeat and look at dial indicator to see if it moves. I recently modified my M Type to Morse No2 taper and had to make a new quill and when I had checked the center the second hand casting I used was about 5 thou low so I had to shim between the top and bottom castings. I hope this helps and as previously mentioned check the clamp down bolts are tight when checking, slacken to adjust with cross bolt and check that the base clamp is adjusted to clamp on the bed angled piece.

David

I suspect the curve in the worn bed section stops the tailstock from clamping firmly and the resulting slight movements cause the tailstock to tilt on the curve, amplifying the error. Although the tailstock can be set straight on the worn section to do a job, it can't be trusted to stay that way.

Can the Drummond's clamp mechanism be tweaked to grip a bit harder? If so, it would be less inclined to move.

The downside of owning worn or made-down-to-a-price machine tools is the operator has to compensate for shortcomings, such as always having to check and reset the tailstock on a worn bed. In comparison, driving good condition industrial kit is a doddle! Conclusion: real men get results from wonky lathes. It's only third-raters who must have perfect kit!

Dave

Daniel check your message box top of web page inbox.

David

If the bed is worn enough to give 10 thou tailstock offset you might as well throw it away. Luckily it's unlikely a Drummond has worn that much (although possible).

The M-Type has a very stout tailstock to bed clamping mechanism that can (and must) be adjusted. It capitalises on the 45-degree angle of the front vertical surface of the front bed way, locking the tailstock in on the angle much the way a V bed lathe does. This aspect of the Drummond is far superior to the Myford cheaper-to-manufacture square-sided flat bed ways. The Drummond tailstock then does not run on the inner vertical shear surfaces of the bed so is not affected by wear there caused by the carraige in the way a Myford is.

Most likely a bit of careful inspection and adjustment will have the old girl on the straight and narrow again.

I think SOD was almost there but it i not the bed wear you need to think about but the tailstock body reference edge (as with the saddle) which will have worn to a slight banana shape. every now and then a bit of swarf will get in there too as you move it around, then be cleared next time you move in the opposite direction.

As for suggesting a lathe should be scrapped just for a little aging - shame. Just relegate it to rough work and woodturning,.

Thanks for the replies. I've had it in bits and it looks to me like the 2 eyed bolts which the tailstock spindle/lever runs through have been made by someone. They've definitely been ground manually on a bench grinder at one end. Also the small cast plate which sits underneath at the rear seems to be a particularly bad fit (the casting edges don't match up) and makes me wonder if it's from another model.

By the way - myford offer a bed regrind service 495 quid mind you. But I'm considering getting it done

Pics of what you found would be helpful.

The cast plate on the rear side should be stepped and have two dowel pin holes that locate it to the tailstock body but let it move up and down. On the front side, the eye-bolt should attach into a wedged block that locks up against the angled surface of the front bed way, pulling the tailstock hard up against the vertical rear surface of the front bed way, which is what sets your Y axis alignment of the tailstock base. Any swarf in that interface or other debris or burrs etc with upset alignment.

You might want to measure how much bed wear you have before springing for a regrind, even if just with a steel ruler and feeler gauges. Three thou wear on the vertical surfaces and five thou on the top flat surface is Myford's recommended limit before a regrind is called for. If the bed were too worn you would notice issues with the carriage being tight and loose at different points on the bed if the gibs are set closely.

I did a bit out there tonight and I think it might be when I tap the tool into the morse taper - I tend to give it a good clout, particularly when drilling, so the chuck doesn't spin under torque. By doing this I could reproduce it going out by a few thou. I'll strip it down and put pictures up tomorrow. Watch this space

Thanks

Edited By Daniel Brannan on 20/06/2022 22:20:43

Ps - on the bed wear topic I only just read that message from hopper. I definitely do have tight and loose spots at different points. I'll attempt getting some measurements

So here are some pictures. As you can see the eyed bolts are home grown and that cast plate doesn't look one bit right to me. Also a helpful previous owner has painted over that flat head screw above the square headed alignment bolt. Anyone know what this is? Oil hole?

With regard to wear using a straight edge and feelers I'm seeing a .003 dip on the top flat of the ways and using a caliper square against the 45 degree flat at the side I'm seeing about 0.010 difference between various points up the bed

The two screws under the gib locking plate should not be there. I would remove them, that plate is meant to float independently of the upper section

The bolt under the gib locking plate adjusts the tension of the plate for the main tailstock release/lock lever

The cheesehead screw "locks" the square head bolt in place so it can adjust the upper tailstock section across the base of the tailstock, to the left or to the right, (once the upper tailstock locking down nuts have been slackened )

So you can adjust the upper tailstock with the lower section locked to the bed

The main gripping point is across the main angled shear gib nearest the user, just like with the saddle, and the square gib plate merely tightens down onto the back of the bed, like with the saddle

The bit you've removed and is not in the picture, the 60degree gib, is the bit that actually aligns your tailstock  along the main shear)

Edited By Ady1 on 22/06/2022 00:02:59

Edited By Ady1 on 22/06/2022 00:09:26

Looks about like mine. The eye bolts and cast plate included. Mine does not have the screws in the cast plate but has the holes where they once went. As Ady1 says the angled gib block at the front not showm in your pics is the main locator and requires careful adjustment so it clamps firmly . Then adjust the plate at the back to match it.

If you have 10 thou bed wear that may be part of your problem.

Thanks. I think it's due a strip down and cleanup then if the parts look to be the correct ones. I'll free up that locking screw and re lubricate everything. There could be grease in there from 1921

Messrs Drummond didn't seem to be overly troubled about castings not matching up did they. The headstock to bed match up is quite a thing to behold too 

Edited By Daniel Brannan on 22/06/2022 10:53:28

Castings are castings. The shape varies a lot. They are molten metal poured into a hole in the dirt. It's the machined surfaces that are important.

Hi Daniel

I have some spare tailstock parts.

You can have them if you like, They may help you.

P.M. me if you do.

Geoff

Thanks Geoff. To be honest it looks like what I have is complete as yours looks the same as what I've got. Thanks for the offer though