Bench Grinders & Lathe Tools.

[chipenter]

I clamped my grinder to the bed but only did one end for a diamond wheel , had to take very small cuts and it still took the edge off the tool .

[Pete W.]

Well, I've been pottering on with my project which is to fit my desk with a pillar bearing two jointed arms, one to support the phone and the other to support a computer monitor.  The pillar is 1½" in diameter and has a series of circumferential grooves.  A plastic clip with an internal rib that fits into the groove supports the hub at the end of the arm.  Because I bought most of the kit on eBay I don't have the clips and the arm is not a current model so there don't seem to be spares available.

I'm making my clips from black Delrin and I've got most operations complete on the outer end of a piece of Delrin rod.  The next operation is to use a form tool to machine the internal rib.  (See sketch.)

I decided I didn't like any of my existing boring bars so I chucked a length of ½" x ½" mild steel bar in my self-centering four-jaw chuck, faced the ends and centre drilled.  I obviously didn't 'hold my mouth right' because the tip of the centre drill broke off!  I just cut that end off the bar, refaced and continued.  I drilled each end tapping size for 2 BA and tapped them.  Then I marked out and drilled and reamed a ¼" cross hole at each end of the bar.  All standard stuff, so I didn't bother with photos.

The plan was for the bar to take ¼" square bits at one end and ¼" diameter bits at the other so I set to to file one of the round holes to ¼" square.  That didn't turn out as well as I'd hoped - a piece of ¼" square HSS fits and the 2 BA grub screw holds it OK but if I hold it up to the light I can see daylight where I'd rather not!

My piece of ¼" square HSS that I used to gauge the hole is already shaped as a bit and I don't want to modify it.  So I need to grind a fresh piece.  Not long ago, I gathered together all my stock of HSS into one place but it's been borrowed by the shed gremlins, very annoying.           So work is currently stalled until I can find it.

The  sketch shows the cross-section of the Delrin bar with the internal rib and the form tool in the boring bar.  It also shows a parting tool ready to part off the ring once the rib is formed.  Then I repeat to get a second ring. 

[Houtenkrullen]

It's an elderly Wolf double-ended grinder fitted with two shaft extensions to take the polishing mops.

Maybe a stupid question, but is it a single phase grinder, or a modified 3 phase?
I didn't know the wolf brand before I was given an old grinder that I am overhauling, but mine definitely is a 3 phase machine. Because of my lack of knowledge of the brand it is definitely very possible or even likely they also made single phase bench grinders, but I thought it might be worth mentioning. I am impressed with the quality of my machine though! I am even going through the trouble to make modern bearings fit ( because I can't get the original Imperial bearings new). To bad the beautiful brand shield is missing...
Peter

[Pete W.]

Hi there, Peter,

Thank you for your post.  In answer to your question - Simon was eager to get his polishing job finished and so I didn't investigate the stator configuration closely.  It was enough at the time to just check the windings for freedom from damage and to fit a replacement capacitor.  I can't remember the details of the winding resistance measurements but they seemed appropriate to a single phase machine run & start windings.