Member postings for Patrick Galvin

The bearings in my lathe were mismatched.The front one was a sealed bearing but the back was not sealed.I damaged the back one taking it out.I was relieved when the new bearings got stuck that I hadn't damaged them.Thanks Pat.

Hi Neil,thats exactly what I did,over tightened them.The back bearing was the one giving me trouble just a bit too tight and difficult to adjust but after 4 efforts I got it spot on.I had to loosen the bearing by giving the end of the shaft a slight tap and then recommence adjusting.I marked the nut and thread as I tightened it with a white pencil so to know where I reached the right spot.I overshot it a few times but had my reference marks to go back to on the next attempt.After running for half an hour at top revs the casting is barely warm.If I ever I have to remove the shaft again I will lap it more under the back bearing to make it easier fitting.I've learned a lot during this exercise and still learning.I'll check out the home page google search . Thanks Pat.

Radial play almost zero.Everything running great.I had a screw loose under the saddle which was causing slight vibration but once tightened everything is good.Just as an observation these machines from Amadeal have a grub screw and nut missing from underneath the saddle from the factory because it would interfere with the gear and prevent meshing with the leadscrew.A design fault.Thanks for everyones help.Pat.

I'll check the spindle for radial play tomorrow.Thanks.

I got the bearings moving again.I didn't remove the bearings to check for damage as it would require a complete strip down so I decided to try adjusting them and see what sort of finish I'd get. I have them adjusted to give me a decent finish on brass and steel.Though I'm getting a fairly good finish on Delrin its not as good as I was getting with plain bearings.

Hi Pete Cordell while waiting for access to a press I managed to free it up myself thanks.If the bearings were damaged I was going to change back to ordinary bearings as you suggested.These are going in the right direction so I'll persevere some more.Thanks

I polished the shaft before fitting the bearings because there were some score marks underneath where the front bearing sits.Not from anything i done but from the factory.The back bearing was very tight to get off so I lapped that point a good bit but it was still tight when I fitted the new bearing.It had to be pressed on.The good news.I managed to free up the stuck bearings and slowly began retightening the nuts to torque the bearings.The chuck is spinning nice and free now and as I go I'm doing test cuts.Much better,the finish is improving every time I tighten the bearings more.The wrench I have is a home made affair with about a 3" handle so I can't tighten it much more though I feel it will take a bit more.Is there any way of knowing when to stop.The finish at the moment is fairly good on free machining steel using HSS cutter but not as good using carbide.

I completely cleaned and dried everything before assembly.I've just remembered I put a light greasing between both parts of the bearings.Probably a mistake?Anyway I set up a puller using 12mm all thread through the bore but I can't get any movement out of the bearings.They're stuck on rock solid.

Edited By Patrick Galvin on 17/09/2020 12:10:22

Hi Ady1 I'm having trouble getting any movement freeing it up and I'm afraid I'll break something if I put any more pressure on it.That sounds like a good deduction,if the back bearing was misaligned by the time I put the chuck on the front I would be moving further away from the front bearing and into chatter at the cut.Your right Pete I need to find someone with a press.Thanks.

I loosened the two nuts completely and ran the machine hoping it might relax a possibly tight bearing but no such luck.When the lathe did warm up after first turning it on it was the back end that heated first.

Hi All,I have an Amadeal CJ18A mini lathe in which I damaged a plastic Hi/Lo gear and needed it replaced.I decided to put in metal gears and at the same time replace the bearings with tapered roller bearings.It took a lot of work as there were quite a few issues when I opened the machine but nothing serious.I lapped the shaft where the bearings were fitting and installed everything.The rear bearing was definitely tighter on the shaft than the front bearing.I tightened everything up and reassembeled the lathe and started it up.Everything ok.I tested runout with a clock at the chuck end,very good.After runing the machine for half an hour at different speeds it got hot but not that you couldn't hold it.I tried cutting metal DISASTER turns out like a hammered finish on longitudinal cuts,ok on end cuts.I thought I had a bearing too tight so I set up a jig to pull the bearings a bit but it wouldn't budge.Is a bearing faulty or is it stuck on the shaft please?When I spin the chuck by hand it seems tighter than I think it should.In high gear at top revs with nothing in the chuck it will spin for a few seconds and cut out.I presume because too much friction?

Hi Ron,I have the same lathe and I made the front parting off toolholder for use upside down with the lathe ran in reverse as recommended by David Fenner in his book The Mini-Lathe.It has the very same effect as a rere parting off in forward motion.It works really well with clean parting and no breaks.