Thread: File & Emery

Hey,

Just cut a couple of MT3 tapers, final finish with a shear tool - they fit nicely with no wobble but the finish isnt quite as nice as I have managed in the past.

(Finishing always seems to be a bit of a lottery for me but in the long term am trending better finishes and slowly understanding more, my best ever finish was as smooth as glass on a daggy bit of black bar using a shear tool - the frustrating thing is that I wasnt able to duplicate that this time)

I've never doe a file or emery finish on the lathe, If I try to tidy it further with a file or some emery paper do I risk ruining the overall taper shape and get a wobbly fit or is the amount taken off too infinitessimally small to make any discernible difference to the overall fit ?

Bill

Hi Bill

If you are not getting a consistent nice finish with your finishing tool, there must be something wrong .

Have you tried the orthodox type tools for finishing ?

Maybe your tools are not sharp enough .

Look around for something like this , a silicon carbide oil stone , the box instructions say a light oil is sufficient but you can also soak the stone in hot petroleum jelly . I found this at a swap meet for a few bucks , it puts a very sharp edge on HSS tools .Mike

Originally Posted by steamingbill

Hey,

Just cut a couple of MT3 tapers, final finish with a shear tool - they fit nicely with no wobble but the finish isnt quite as nice as I have managed in the past.

(Finishing always seems to be a bit of a lottery for me but in the long term am trending better finishes and slowly understanding more, my best ever finish was as smooth as glass on a daggy bit of black bar using a shear tool - the frustrating thing is that I wasnt able to duplicate that this time)

I've never doe a file or emery finish on the lathe, If I try to tidy it further with a file or some emery paper do I risk ruining the overall taper shape and get a wobbly fit or is the amount taken off too infinitessimally small to make any discernible difference to the overall fit ?

Bill

You won't ruin the fit on a taper by polishing, just get some fine wet and dry and have at it. Check the fit with a bit of bearing blue, and concentrate the polishing on the blue bits, until the blue bits get bigger.

Ray

Yes, this is the go !
Bruce

Using a file or emery to finish is frowned on in some circles. Just watch out for the chuck jaws with the file and maybe make up and emery stick. Its no fun with the emery wraps itself around the work if you're holding onto it.

Stuart

I emery alot of thing at work. I would recomend using a small piece so it cannot wrap around.the workpiece 400 grit works for me.

Thanks for the tips - tried a small piece of emery paper plus some cutting oil - did the job fine.

Yes Morrisman you are probably right - probably something wrong with the shear tool that I didnt notice but I always wanted to try this emery caper cos I'd read about it so much in old books and magazines.

I get the impression that lots of people do this but it is often warned against in books or a manuals. The other one I wonder about is grinding on the side of the wheel - I get the impression that this too is widely practiced but formally frowned upon. I have used the side of the wheel at times.

I drilled out the taper today and fitted a threaded bar through it - am making one of those fancy George Thomas backstops for a chuck - was ever so chuffed when my two drill holes met inside the workpiece. I knew it was theoretically possible but thats always different to actually doing it.

Bill

Originally Posted by steamingbill

... tried a small piece of emery paper plus some cutting oil - did the job fine.I get the impression that lots of people do this but it is often warned against in books or a manuals. The other one I wonder about is grinding on the side of the wheel - I get the impression that this too is widely practiced but formally frowned upon. I have used the side of the wheel at times.

Emery in the lathe is warned against for two reasons I can think of - one is that loose grit can fall onto the lathe bed and so abrade it over time, the other is that if the emery gets caught and wraps around the job, you could be wrapped with it. The side of the wheel thing is probably more about undercutting the peripheral surface which may then chip/ spall and all the fun things that go into a cracked and/ or out of balance wheel.

Like most things which you should not officially do, it is as much about being careful about what you are doing and how often against what the consequences are. A light touch on the side of a grinding wheel occasionally would be completely different from using it as your primary grinding surface on a daily basis. (There is a different type of grinding wheel available if that's your thing).
As for using emery, on one forum I mentioned doing that and it was implied that the world was about to end and it would be my fault because of my actions - and then one of the more respected contributors came along and said he did it all the time and what was the issue, at which point opposition melted away...

Michael

Originally Posted by Michael G

and then one of the more respected contributors came along and said he did it all the time and what was the issue, at which point opposition melted away...

funny that

Originally Posted by morrisman

Hi Bill

If you are not getting a consistent nice finish with your finishing tool, there must be something wrong .

Have you tried the orthodox type tools for finishing ?

Maybe your tools are not sharp enough .

Look around for something like this , a silicon carbide oil stone , the box instructions say a light oil is sufficient but you can also soak the stone in hot petroleum jelly . I found this at a swap meet for a few bucks , it puts a very sharp edge on HSS tools .Mike

Fixed

I had another go this afternoon and in a fairly disciplined and methodical fashion I counted 1 thousand 2 thousand etc taking a total of 8 thousand for every full turn of the compound - got the nice smooth finish again.

Bill