Thread: head stock bearing bolts

Hi Tanii

If your lathe still has the original shims, one of the shims in each bearing will be laminated. You can peal off layers to tighten up the bearings.

5 thou coke can is awful fat for a change in headstock bearing clearance. I would do the following. Take out the minimum amount of shims, be it ones you've made or the laminated ones till the play tightens up. If it is too tight, don't get fussed about the shims, just do the following. Leave the shims as are and loosen the bolts until the spindle turns freely. Now you can adjust the tension of the bolts. The bearings, with oil (and you must always have oil, replenish often) will get warm at the top speed, but should never get hot too the touch. If they get hot without running out of oil you've done the adjustment bolts up too tight.

If you have a face plate you can put it on and shake it with all your strength, if there is play in the front bearing you will feel it. A length of steel bar in the chuck could also be used.

Personally I had no shims in my lathe for years, the only difference, as far as I could tell upon putting them in, is that the oil runs out of the bearings a little slower

sorry should have said im using 4 layers of shims to replace one of the 2 already in there.it appears that they are not original ( no brass laminations) just using the aluminium to work out what size single one i need+1fine adjust ment one .The one im removing is .018 inch .i think i can probably revert to the original as there is only .003 play vertical ( push down then up). maybe im being too fussy

Whether you're being too fussy or not is your call. I think you should be able to get it going well without getting the shims perfect.

Let us know how you go with oil running out of the bearings. I'm still not real happy with the rate oil runs out of mine. My bearing have virtually no play when the bolts are loose and it's real hard to get enough shims in them. I used gasket paper for the last shim.

Oh, you probably want to get it down to at most 1 thou. If the bearings are real worn you may have to settle with the 3 thou. I had a real worn southbend with no shims, I could still tighten that up such that the spindle started to bind no problems.

At the end of the day it will probably work with the play for ordinary turning. Trying to part off will probably be hopeless though. Expect many a catastrophic dig in.

thanks for the advice well i can certainly lock it up by tightening the bolts at the moment ive just got it so it just spins freely and doesnt get too warm and yes a little oil seeps from the bearing but we will see what happens . my first go at serious stuff today facing off an old back plate to fit a chinese face plate one i got cheap. first lesson
if you dont do up that bolt on the apron that locks it you will get a convex shape

I found some proper instructions for how to adjust the bearings on a 9" Southbend. Of course that's the same as the Hercus.

http://www.wswells.com/data/howto/Sp..._Adj_9_10k.pdf

They recomend 1 to 1.5 thou movement for cast iron bearings, which is what the Hercus has.

Anyway good to hear you're making chips Tanii