Any tips for tailstock adjustments on a mini lathe?

[tinglett]

Hey all,

I'm going through some adjustments on my mini-lathe and am (finally!) turning on centers.  I had already lined things up with a 1" rod extended from my 4-jaw chuck and all is well, so I figured turning between centers and adjusting the tailstock was the next step.

First, a photo of the ugly setup.  I am unhappy that my MT3 dead center is HUGE for this lathe.  Are shorter ones available?  I'm under the assumption it's hardened and not realistic to machine it down.   Driving the dog seems a bit precarious to me, not to mention the wasted space on a lathe that has little to spare.


After turning this rod, I found the tailstock end was 0.012 inch larger in diameter.  I found I had to loosen a little slotted screw on the end, but there was also a socket cap head screw underneath the tailstock.  Has anyone found a way to get under there without removing the tailstock?

I found I had to loosen the screw underneath while the slotted screw remained tight, reinstall the tailstock, loosen the slotted screw, tap very carefully with a DI measuring my progress, tighten the slotted screw, *CAREFULLY* pull off the tailstock, flip over, and tighten the socket cap screw.   Geez...can they make it any easier?  On my first attempt I tapped away 0.006 inch, but managed to go over a bit.  It's now 0.003 under.

I'm sure I can get it on the next couple attempts, but I'm posting on the off chance there is a better way.  I'd like to be able to turn tapers and don't want to fear messing with the tailstock.

Todd

[sshire]

Todd
Every lathe that I've owned has two setscrews. One on each side of the tailstock. They face each other. One is loosened and the other is tightened. MrPete has a good YouTube video on tailstock adjustment.

[Roger B]

My mini lathe does not have the screw from underneath fitted. I had always assumed that it was meant to be some sort of shoulder bolt to limit the travel rather than a clamp. The main clamping is done by the tailstock clamp bolt so maybe you can convert it to a shoulder bolt or just leave it out.
What I did find was that the surfaces that the tailstock slides across on were bad making fine adjustments very difficult. This thread describes some of the fun 

http://www.modelenginemaker.com/index.php?topic=2866.15

Your MT3 center looks much like mine when you consider I have the faceplate fitted.

[Nickle]

Hello,

Aligning a mini lathe turns into a project all of its own. There is a good chance that more than your tailstock is askew. I think it is worth the effort to sort it all out though.

A good description of one approach to process is available on the website below

http://www.gadgetbuilder.com/Lathe_Align.html

My mini lathe now has little tabs of foil hanging out of most of the critical mating surfaces to correct alignment issues. I can now turn things parallel over 100mm plus without being able to measure a difference in diameter end to end (last time I checked anyway, it may have shifted).

 For the horizontal alignment of the tailstock I found that adding an adjustable stop to the back of the tailstock helped with repeatability when trying to make minute adjustments.

Littlemachineshop have a much nicer looking version than my own shown in the link below.

http://www.littlemachineshop.com/Projects/TailstockAdjuster.php

I hope this helps you get everything pointed in the right direction.

Regards,

Nick

[chucketn]

Todd, here is a write-up on several mods to the C2-C3 tail stock.

http://mikesworkshop.weebly.com/tailstock-modifications.html

Scroll down to the 2nd topic under "Addressing the issues". Mikey modified that screw underneath to be accessible from above. I did this mod to my tailstock, and it works great. Mikey showes many other good mods there. I added some more screws to facilitate allignment.
I can take some pics of my TS mods if needed.
BTW, I'm getting ready to machine a Dividing Head spindle between centers, myself.

Chuck

[tinglett]

Thanks all for the pointers!   I was thinking of making some kind of adjuster, but for some reason I was only considering something on the front (facing me) side of the tailstock rather than the back.   I'd better also pull apart the tailstock and look for trouble spots while I'm at it.

I'll need to check perpendicular alignment of the cross slide using the method described over in Roger's thread.  I was planning to simply face something and make sure it was flat or concave.  This is a better method, though I'm not quite sure how to fix that if I find a problem.  For now I'll cross my fingers.

Again, thanks for the pointers!  Hopefully I can get this lathe tuned up a bit more and get going on the next engine.  So far the lathe has been workable, and most of its flaws are masked by the inexperience of the operator anyway.  But I figure with each project I should try to make the machine just a little bit better.

BTW, I'm not entirely sure I categorized this thread right.  An op can feel free to move it if you want.

Todd

[gmac]

Todd;

You may have found some of this, but just in case;

http://warhammer.mcc.virginia.edu/ty/7x10/vault/Members/RickKruger/Tailstock/SetOver/index.html

http://warhammer.mcc.virginia.edu/ty/7x10/tstock.pdf

http://www.mini-lathe.com/Mini_lathe/Tuning/tuning.htm#Adjusting the Tailstock (06-04-12)

http://www.varmintal.com/alath.htm#Mini_Lathe

http://www.ddenker.com/Machineshop3.htm#L1

http://www.mini-lathe.com/Default.htm

Cheers Garry

[mklotz]

Driving the dog seems a bit precarious to me, not to mention the wasted space on a lathe that has little to spare.

An alternate approach...

Chuck a bit of scrap and turn a 60 deg point on it.  Since it is turned in situ it will be more accurately centered than your over long center.  Don't remove it from the chuck.

Now drill a shallow, off-center hole in the headstock end of your stock and insert a pin just long enough to reach the chuck jaws.  The pin will drive the stock while turning and, in most cases, the end with the pin hole can be turned off after the piece is finished.