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Need help with drill spindle!

Dai, do you have 60-deg center drill holes on one or both ends of the spindle? ie. something that the shaft could be located relative to its original center axis in a lathe? The hole would look like made from this kind of drill profile. At least one center (for tailstock) would come in handy when the time comes to deal with your bump, but also I had a thought. If the shim was oversize, it could be turned/finished down to desired diameter as long as it was well bonded to the shaft. Well... brass could be turned, but steel shim would be challenging because I think its typically hardened. Now if the shaft had a bit of wobble in the bearing area then that would defeats the purpose because it would cut eccentric. Personally I think finding the right shim is just easier solution to try first so no need to make it more complicated yet. But I'm curious about this bonding business now. I will do a little experiment.
 

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I saw somewhere that knurling was used to bump the shaft diameter but I don't know if it would be enough or work in this case.
 
i have used knurling before - only good for about 1-2thou (4 total on the OD).

i think one of the pictures shows a center. The ends have been hammered (the bulges Dai wants removed). The centres are probably in need of a re-cut.
 
PeterT said:
Dai, do you have 60-deg center drill holes on one or both ends of the spindle? ie. something that the shaft could be located relative to its original center axis in a lathe? The hole would look like made from this kind of drill profile. At least one center (for tailstock) would come in handy when the time comes to deal with your bump, but also I had a thought. If the shim was oversize, it could be turned/finished down to desired diameter as long as it was well bonded to the shaft. Well... brass could be turned, but steel shim would be challenging because I think its typically hardened. Now if the shaft had a bit of wobble in the bearing area then that would defeats the purpose because it would cut eccentric. Personally I think finding the right shim is just easier solution to try first so no need to make it more complicated yet. But I'm curious about this bonding business now. I will do a little experiment.
Click to expand...
No, there is no hole on either side of the spindle. I think you are right about finding the right shim first before we go crazy on it. Beside, my measurement maybe off so when Chad put the spindle on his lathe, he could double check the diameter of the spindle.
Edit: My bad, there is a hole on the tail side of the spindle.
Edit #2: I just checked the spindle and it does have centre holes on both side. LOL
 
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The knurl isn't difficult to produce and I'm not sure if it would flatten out over time. Some one with more time in than me may be able to answer flattening out question.
 
YotaBota said:
The knurl isn't difficult to produce and I'm not sure if it would flatten out over time. Some one with more time in than me may be able to answer flattening out question.
Click to expand...
It doesn’t even have to be a knurl
One old trick with a worn part was to take a centre punch and just add a few dimples to the shaft to raise up some meat. Add some green loctite and tap the bearing into place

If the bearing isn’t spinning on the shaft there’s no reason why the dimples won’t last for a long time
 
Chicken lights said:
It doesn’t even have to be a knurl
One old trick with a worn part was to take a centre punch and just add a few dimples to the shaft to raise up some meat. Add some green loctite and tap the bearing into place

If the bearing isn’t spinning on the shaft there’s no reason why the dimples won’t last for a long time
Click to expand...
My only concern about this is the bearing won't be true to the centre of the spindle.
 
Chicken lights said:
It doesn’t even have to be a knurl
One old trick with a worn part was to take a centre punch and just add a few dimples to the shaft to raise up some meat. Add some green loctite and tap the bearing into place

If the bearing isn’t spinning on the shaft there’s no reason why the dimples won’t last for a long time
Click to expand...

I’ve used that on a auto advance shaft on my Norton years ago the play would change the timing So it would kick back when starting it and the shop I bought it from was baffled It worked great till a replacement arrive.
 
Well my first little experiment was a fail. I turned a blank of regular 1018 steel & attempted to Loctite a 0.5" wide strip of 0.005" brass shim on the OD with retaining compound. I wrapped it tightly with tape to conform. That part went well. But next day (cured) the brass basically popped off but the glue was fully cured hard on the steel. It had to be re-machined off. Both surfaces were clean & wiped with non-oil spirits. This was #680 0.015" gap fill. I know this stuff works reliably & predictably steel on steel. And I also discovered it locks up extra fast bronze and aluminum. I guess I haven' had much experience with brass but wasn't expecting any surprises. If push comes to shove there is always epoxy but I was tryng the so called obvious solution first. I'll upload some pics when I get to them. Tonight I tried again with Loctite primer/accelerator on the brass & a different #PN on another strip.
 
Thanks for your time experimenting the brass shim. I wonder if the brass shim is loctite to the bearing ID rather than on the shaft but this method would have to press the bearing onto the shaft and hope that the brass shim won't come out.
 
That could be an option too but the issue I want to solve is bonding the brass to steel, be it the bearing or the shaft. Didn’t think it would be a problem. I’ll know more tomorrow. BTW curling the brass around a rod & using tape to assist was ok, I even pre curled it a bit. Steel might be stiffer yet. But I think conforming it to an ID would be a bit more fiddling unless the shaft fit just right to kind of press & hold into position till the glue set. TBC
 
Brent, have you tried 660 specifically with brass & steel? I ran out of time yesterday but I did find Google references to brass being an odd duck & not bonding well, or at least the same as typical steel to steel. Like I mentioned, the glue was completely cured & bonded to the steel but basically no bond to the brass side. The Loctite cross reference charts seem to be indicating use of primer and or other products like 'purple'. I'll see tonight what my results using red & 680 with primer look like tonight. #680 has 0.015" gap so I'm thinking helpful under normal circumstances, but maybe not the important parameter when it comes to brass at least. Who knew.
 
Would it be possible to machine a interference fit that is shrunk on the shaft then turn it to size. I think it would work ok they say it’s permanent.
 
@PeterT : I machined a bore into steel for a bronze bushing that I got just a bit larger than the fit I wanted. I used that stuff to take up the difference in the bore- cleaned both parts with acetone, applied the 660 and then slid them together - but did not push the bushing all in, was going to set the piece on a flat surface to ensure the surfaces were true - flipped the piece over and - nope the bushing was stuck fast and would not budge, had to machine off the 1/16" of stick out I had left. Made a super tight joint.

If the bearing in question is riding on the end of the shaft and you can turn it to reduce the diameter for a sleeve then the sleeve should work fine - add some red loctite for added security and re-machine to 0.625 and then press on the bearing. If the wear area is in the middle of the shaft and no way to sleeve it then you could spray weld. Is there any reason not to make a new shaft? Is there any special details that prevent this? - I will read the total post and see what we are discussing - LOL
 
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