Unimat Lathe Cross Slide and Dial Indicator Anvil Locking Screws

[Paul Jones]

The Unimat SL 1000 lathe uses a socket head cap screw (SHCS) in the top of the cross slide for locking the cross slide. However, access to the SHCS can be blocked by accessories bolted to the cross slide such as a QCTP or milling table. I now use the factory installed locking screw for only adjusting the cross slide backlash and have installed a new locking screw on the side of the cross slide.

The new locking screw locks against the left-hand cross slide rail and is a 10-32 SHCS with a knurled ring added to the screw head. The new locking screw can be locked with a hex key for milling operations or just thumb tightened for lathe work. The 21 pitch knurled ring was machined from 0.364” dia. 303 stainless steel and bored to a press fit and fastened with Loctite 680 retaining compound.

This locking screw arrangement works so well that I made another one for locking an adjustable sliding anvil for the cross slide dial indicator. The dial indicator is limited to a 1” travel and must be adjusted within the 1” range depending upon the tooling set-up on the cross slide. The differences in set-ups between lathe work and vertical milling work requires this level of flexibility for the dial indicator. I use a 2” dial indicator on the longitudinal movement but decided to use the 1” dial indicator on the cross feed to limit the weight of the overhanging dial indicator (see http://www.homemadetools.net/forum/c...ndicator-17160 for more details on the cross slide dial indicator to the Unimat lathe).

More information and photos to the Unimat Sl 1000 lathe improvements can be seen at http://www.homemadetools.net/lathe-modifications .

[DIYer]

Thanks Paul! We've added your Lathe Locking Screws to our Lathe Accessories category, as well as to your builder page: Paul Jones' Homemade Tools. Your receipt:

Lathe Locking Screws by Paul Jones

tags: lathe

[PJs]

Thanks Paul! Great Pictures and write up. Really clever idea for the knurled nut with access for the allen wrench. Beautiful knurling too! Did you put a brass pill in the bottom of the hole to keep from galling your cross slide rails? Really like the extender rod on the dial gauge too...out of the way and makes it always in range...Nice! Thanks! ~PJ

[Paul Jones]

Thank you PJs and happy New Year.

I installed brass nubs on three of my other M6 threaded knurled clamps for the Unimat but not on these two that are 10-32 stainless steel SHCS. So far with 18 months of use there are no signs of galling the cross slide rail or the O-1 drill rod for the dial indicator. The adjustable drill rod anvil for the dial indicator makes the DI very useful.

Thanks again, Paul

[PJs]

Happy New Year to you too Paul.

I remembered your brass tip trick and just wondered. If it hasn't done it in a year and a half, probably no need on this application. Thanks again for sharing your innovations! ~PJ

[dethrow55]

The Unimat SL 1000 lathe uses a socket head cap screw (SHCS) in the top of the cross slide for locking the cross slide. However, access to the SHCS can be blocked by accessories bolted to the cross slide such as a QCTP or milling table. I now use the factory installed locking screw for only adjusting the cross slide backlash and have installed a new locking screw on the side of the cross slide.

The new locking screw locks against the left-hand cross slide rail and is a 10-32 SHCS with a knurled ring added to the screw head. The new locking screw can be locked with a hex key for milling operations or just thumb tightened for lathe work. The 21 pitch knurled ring was machined from 0.364” dia. 303 stainless steel and bored to a press fit and fastened with Loctite 680 retaining compound.

This locking screw arrangement works so well that I made another one for locking an adjustable sliding anvil for the cross slide dial indicator. The dial indicator is limited to a 1” travel and must be adjusted within the 1” range depending upon the tooling set-up on the cross slide. The differences in set-ups between lathe work and vertical milling work requires this level of flexibility for the dial indicator. I use a 2” dial indicator on the longitudinal movement but decided to use the 1” dial indicator on the cross feed to limit the weight of the overhanging dial indicator (see http://www.homemadetools.net/forum/c...ndicator-17160 for more details on the cross slide dial indicator to the Unimat lathe).

More information and photos to the Unimat Sl 1000 lathe improvements can be seen at Homemade Lathe Modifications - HomemadeTools.net .

great idea i have a unimat actually two and have this same issiue.

[Paul Jones]

Thank you dethrow55.

You may already know this from your experience with the 3" swing Unimat but I discovered the two rods for the cross slide are not perfectly parallel horizontally to the plane of the longitudinal rods on the long axis of the lathe. This makes a difference when milling larger parts using the vertical milling head either at the headstock end or the way I have it set up near the middle. Above in the first three photos you can see a small set screw holding the left-side rod for the cross slide.

I removed a few thousands off the bottom of the hole for the rod and the small set screw forces the rod downward allowing all the machining planes to become parallel. I have more details about this adjustment on the second page entitled "Aligning all six different Unimat parameters for X, Y, Z, roll, pitch, and yaw" at http://www.homemadetools.net/forum/m...-lathe-10111-2 ). It is an easy fix and makes a big difference when fly cutting larger parts.

Regards,

Paul Jones

[mr mikey]

Great idea. thank you. Mr Mikey.