# Another Mini Lathe Compound Bearing Mod



## keithvi (Dec 11, 2015)

A simple project to improve the compound function using two 6700zz bearings (10mmID x 15mmOD x 4mmWidth)

Using some aluminum bar I made a new round dial that bolts to the compound slide with two m4 socket head screws. aka: "Retainer, Compound Rest Screw".  I did this to keep my old dial in case this did not work.  Doing it this way I was able to use my lathe throughout the build.

Bored the slide facing side of the new dial for the bearing 15mm x 6mm and pressed in the 1st 6700zz bearing to assist with forward thrust.

I made the second bearing housing fit behind the "Retainer, Compound Rest" (under the edge of the compound slide) to contain the 2nd bearing to assist with the reverse thrust.

The mod worked to prevent the compound screw from forcing the dial and the retainer together.  I am able to snug the compound gib adjustments and still smoothly adjust the compound without binding the dial.  I have included a Sketchup drawing and a photo.  With this modification I lost only 4mm of forward compound adjustment (my compound would already bind 3mm short of full forward so adding the 7mm bearing house under the slide only cost 4mm of travel)

Notes: The only original part slightly modified was my gib strip (moved forward a few mm & I corrected for the new gib adjustment screw detents. Everything about this bearing modification is reversible.  The bearings are dirt cheap on ebay.  My lathe is a 7 x 12 Baileigh (typical Chinese mini 7x lathe)


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## T Bredehoft (Dec 11, 2015)

Good Idea, I'm doing this on my PM25 mill on the X lead screw. It reduces the effort to turn the crank.


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## NEL957 (Mar 14, 2016)

would not adding a thrust bearing on top of the 6700zz bearings be better? The side pressure converts to drag and makes turning it hard.


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