Scratched Spindle

[ieezitin]

Good Evening Ladies and Gentlemen,

I noticed this afternoon while turning between centers i have a scratch inside my spindlenose right where the MT sleeve sits, I must have had a little debris between the sleeve and it spun in the bore, i an thinking about lapping it with crocas cloth on a round sided wooden stick to lap it out, before i do so how would you do it?

Thanks in Advance,                                    

Anthony.

[PixMan]

So it's a concentric scratch and not a longitudinal one?

Crocus cloth on a wooden stick isn't going to do anything but polish it. Use a round of brass and some 240 or 320 grit aluminum oxide or silicon carbide bonded abrasive (sandpaper.) Only after using that to assure there's no burrs or lumps of built-up material should you polish with the crocus cloth on a wood dowel.

[f350ca]

How deep is the scratch? I'd blue a good MT and see where things are touching. Abrasives will remove high spots but also some material (maybe very little) at the end of the abrasive where it contacts the bore. If the scratch is deep with a burr on the sides I'd be tempted to use a curved bladed scraper to cut only the high spots or a small wheel on a die grinder to lower the high spots leaving the rest untouched.
I recently had to do this to the tapper on my 3 jaw where it contacts the spindle on my Hardinge. The jaws need ground to remove a bell mouth. I was checking the unworn backs of the jaws with a dial test indicator before grinding and saw they were out. Close inspection showed a small dent on the end of the mount, that deformed the inside surface. Blueing showed that side of the tapper was not contacting. I used a small scrapper to lower that section. When I tried to check it again with the blueing it locked to the spindle, the way it should. Very light pressure showed a nice even coverage hence contact.
Emery paper would have removed material that should have stayed there. You want to only clean up the damage.

[ieezitin]

Some great insight here....Im going to do a blue test and see what i have..

The scratch is rotational in the bore not longitudinal 

Thanks


Anthony.

[Dr Stan]

Another approach would be to make a brass or bronze lap to fit the taper & then charge it with diamond lapping compound.  If you have access to the equipment make an undersized lap from steel then spray weld it with bronze and finish machine it. 
Then charge the bronze with the lapping compound.

Granted this would probably be the most expensive and time consuming way, but it should prove to be very accurate as long as the lap had the proper taper.

I have a set of MT taper hand reamers going up to a #5 (I think).  If you want to use one just PM me.  The only cost will be shipping both ways.

[ieezitin]

Stan

Very decent offer I very much appreciate it... I am going to blue it up see what i get and another suggestion from another forum was to use a half round slipstone to hone it away, i am going to try this first... reaming really would be my last resort... also making the brass lap is a great thought ..... I would never of come up with that..

Again If i go the reamer rout i will hit you up.

Thanks

Anthony.