Restoring dovetail jaws

[rsser]

These need a crisp edge and flat face for best holding.

Terry Martin wrote about how to do this some time ago in Aus. Wood Review.

I was wary but had to bring into play a very worn 50mm set on a SN2 chuck. It was kindly supplied by a forum member as I'd bought a bare chuck.

I'd already learned (once!) that HSS beats medium tensile steel.

So today I had a go at facing off the worn 290378set and it was easy peasy. Just used a HSS scraper as you would on wood. Light touch, medium speed in this case.

This will do the job I need but I imagine the outside of the dovetail could be treated in the same way providing you put some packing in to ensure true circumference and reduce the chance of a disastrous catch.

[Hermit]

Very interesting. Filed away for future reference.
Thanks for sharing.

[TTIT]

..............This will do the job I need but I imagine the outside of the dovetail could be treated in the same way providing you put some packing in to ensure true circumference and reduce the chance of a disastrous catch.Good advice Ern! Not sure about the SN stuff but closing the centre of the jaws on to an 8mm diameter rod will bring Vicmark jaws to a proper circle - the butt of an 8mm drill bit suffices with the nasty end poked into the headstock :U

[NCPaladin]

I use a metal bit installed in a handle which also holds ½” scrapers, bedans, etc. The bits come in a wide variety of shapes and are usually about $3. I modified slightly a set of Nova 35mm spigot jaws.
The bits are only about 4” long but that is long enough. Your turning tools will work but the carbide bits also make quick work of brass or copper ferrules or other items.

According to Nova, the kerf made when the billet is split for jaws is 2mm. For myself I would cut some 2mm thick hardwood strips and place them between the jaws. I haven’t tried it but it should work. You may still get a slight bump but it shouldn’t grab with light cuts.

[rsser]

Thanks for the packing tips folks.

My only prior encounter of this sort was an accidental meeting of bowl gouge and the outside of edge of shark jaws. The gouge sliced small fillets off the high points!

[powderpost]

Good advice Ern! Not sure about the SN stuff but closing the centre of the jaws on to an 8mm diameter rod will bring Vicmark jaws to a proper circle - the butt of an 8mm drill bit suffices with the nasty end poked into the headstock :U
Good tip and just in time to.. DAMHIK.. :-
Jim

[rsser]

If you do this just do a very thorough clean-up of the bed afterwards.

[robo hippy]

After seeing 's clips on chuck maintenance, I was going to ask him about this. I do remember some thing about putting small shims in between the jaws for cleaning up the dove tail angles. I have several tool marks in my chuck jaws. Mostly from my McNaughton.

robo hippy

[dr4g0nfly]

I've never tried to 'scrape' jaws.

My preferred method is a Mill File (for levelling saw teeth) while running at a low speed.

[NeilS]

I've never tried to 'scrape' jaws.

My preferred method is a Mill File (for levelling saw teeth) while running at a low speed.

Good topic, Ern.

I've done it both ways;

The CT tip is quicker, but have gotten a few edge chips off the tip, and the surface is so-so when done by me.

The file tends to follow the ups and downs, so I made up a jig to steady it, and is slower, but leaves a nicer finish.

I found a combination works well; tip followed by file.

But then, I'm not much of a metal worker.

Either way I use a face mask.