Sunday, January 29, 2012

Adding Bearings to Y Axis Part 3 - Bearing Mounted Thrust Collar

This is going to be a long post, combining what I did for the last 2 sessions. Blame BlogPress, if you want to; for whatever reasons, the 2 posts done on BlogPress, one for each session, cannot be uploaded. I've sent a mail to its developer earlier today.  Hope that they sort out the problem soon.

Ok, with the longer leadscrew adaptor completed, I went on to make the other component that made up the whole assembly.  Not knowing what to call it, it should just be known as bearing mount as its role is to hold the 2 flange bearings to the base of the mill where the handwheel is to be mounted on.

The stock I started with was a piece of 40mm diameter aluminium round stock.  It was cut to about 40mm in length on the bandsaw, catering for the the height of the 3-jaw chuck in its reverse position.  The part is supposed to be 12mm thick and so I thought I can make 2 pieces at one go. If I'm successful, I'll have 1 extra to use on the X-axis.

Here goes:

Cutting off a section of 40mm in length. The straightedge clamp to guide the cut.
The end was faced off to "flatten" the sawn surface.
Turning as close to the jaws as I was comfortable with.
The largest center drill in my toolbox was employed.
Drilling through using the largest drill the tailstock drill chuck can take - 10mm diameter, to prepare for boring.
I was trying to use the set of boring tool from Proxxon but they apparently require a bigger bore to start. So the little boring tool was used instead.  I really love this little beast! Very nice finishes can be achieved. The only regret is its short length though - max at 15mm.
After opening the bore to about 12mm in diameter, I tried using the Proxxon boring tool to see how it performs.
Bad Bad Bad... Just look at it! I must have done something wrong... the mini boring tool was mounted back to clean up the mess created and work continued.
Testing how well the bearing fit.  Not tight enough though no wobble felt. One more chance to get it tight when the recess is done to cater for the flange.
I did it again... the recess is a little too deep for my liking, but it is really tight when I press the bearing down with my finger.  So tight that I can remove it with the L-shaped allen key...

I'm now ready to part off the mount to clean up the other side.  I was so confident of the experience I acquired parting off brass and steel that I didn't expect to encounter problem with this piece of aluminium stock - the lathe motor was stalled twice and I've a bad case of chatter.  The part was so hot to touch that I burn my fingers touching it... ouch!

This was where I left the workpiece to cool off while I think through how I should do.

I was standing at the lathe looking at where I stopped the next morning.  The tool was advanced to almost touching the last place where jam occurred the night before.  I turned the chuck by hand to rid of the chips and chatter marks that caused the jam.  For some reasons unknown to me, I opened up the gear box to look at the belt position and realized that it was set to 1400 rpm!  This is too fast from the experience I gathered.  No wonder the feel wasn't right when I feed the tool into the workpiece.  I changed the belt to 330/660 position and selected the slower speed (330 rpm).  The feel is now back!

All the way through!!!  Well done, Wongster!
You can see from this pic that I didn't bore deep enough.
In fact, I was off by quite some bit!
The workpiece was put back into the chuck and faced off to the targeted thickness of 12mm.  There just wasn't enough "meat" after parting to make 2 pieces of the same so I gave up the idea.
Bearings fitted on both sides.
Testing the mount on the mill with the handwheel installed. Please note that the original thrust collar wasn't removed when the modified thrust collar (now I know its name...) was tested.

There is still the 2 mounting holes for the #8-32 capscrews to be added before I can call the job completed.  I'll be making another one as I'm not satisfied with the bearing bore.  With this experience, I hope to do a better job when starting over.

I welcome any suggestion on how I should approach this.

Have a blessed night.

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