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Enfield
05-13-2012, 02:23 AM
Hi Guys
anyone know if you can get parting of tool tips with a rad rather than a straight end. I am making little suppressors baffles (they are legal over here in NZ) and up to now I have been making the little waist with a parting tool but would like to make the waist with a rad rather than parallel section.

See photos the silver parts are what I am making, I would like it as per the black example

http://i49.tinypic.com/2efjd4l.jpg

http://i45.tinypic.com/2znyik9.jpg

http://i47.tinypic.com/eumu0j.jpg

Cheers

Ian B
05-13-2012, 03:09 AM
These any good to you?

http://www.ebay.co.uk/itm/x10-SANDVIK-CARBIDE-GROOVING-INSERTS-N151-2-400-40-4P-235-4MM-WIDE-2MM-RADIUS-/251054847963?pt=UK_BOI_Metalworking_Milling_Weldin g_Metalworking_Supplies_ET&hash=item3a7408f7db

Ian

Enfield
05-13-2012, 03:46 AM
These any good to you?

http://www.ebay.co.uk/itm/x10-SANDVIK-CARBIDE-GROOVING-INSERTS-N151-2-400-40-4P-235-4MM-WIDE-2MM-RADIUS-/251054847963?pt=UK_BOI_Metalworking_Milling_Weldin g_Metalworking_Supplies_ET&hash=item3a7408f7db

Ian

Might do the job - Thanks

Jaakko Fagerlund
05-13-2012, 04:12 AM
Other option is to use a diamond wheel and grind the radius to an existing parting tool, takes all of 1-2 minutes to do it properly :)

quadrod
05-13-2012, 08:15 AM
Just use an HSS parting blade and radius the end on a grinder and then polish with a stone.

PixMan
05-13-2012, 08:35 AM
I have some of those full-radius inserts for my Valenite blades that are 3mm wide (1,5mm radius.) It's the same system hardware as the Sandvik N151.2 shown.

They work quite nice. Those are available for almost any of the single and double ended parting and grooving systems from most of the major carbide insert tooling makers.

I suppose you can grind a regular one, but most of them today have a molded-in chip breaker that would really make for an uneven cutting edge once you carve away sections of it.

In steels with the ones I have, I can actually break chips. In aluminum, not so much.

dockrat
05-13-2012, 12:41 PM
What you are doing is very much like what I do when I am making my oil lamps except I use a DCMT insert instead of a parting tool. These are available with nose radii up to 1/4 inch which should work for you. I plunge cut 20k about 1/4 inch away from the taper then back feed the back side of the insert into the taper then forward feed for the rest of the cut. A posed picture to show what I mean.
http://i253.photobucket.com/albums/hh67/Dockrat1/IMGP1616Medium.jpg

If the back side of the insert is not the right taper you can always turn the tool post a bit. Another picture of the finished product. Works for me. ;)

http://i253.photobucket.com/albums/hh67/Dockrat1/IMGP1512Medium.jpg

Enfield
05-13-2012, 03:40 PM
Thanks gents some good ideas there

Ron of Va
05-13-2012, 06:05 PM
I set my compound to 30º, and start “close to the waist” feed in with the compound for the angle, then out with the cross slide for the base until the baffle takes form (see 7 & 8). I use a HSS ground to a profile I feel will do the job.
Sorry the photos are kind of crappy.
http://www.hunt101.com/data/500/medium/Group1-9.jpg

Enfield
05-13-2012, 08:34 PM
I set my compound to 30º, and start “close to the waist” feed in with the compound for the angle, then out with the cross slide for the base until the baffle takes form (see 7 & 8). I use a HSS ground to a profile I feel will do the job.
Sorry the photos are kind of crappy.
http://www.hunt101.com/data/500/medium/Group1-9.jpg

Thanks Ron
that looks good, seems you are into suppressors to :D

Any chance you could show the tool geometry, particularly the rake and clearance angles. I guess you are cutting towards the chuck, making the cone deeper and deeper until you are down to depth then just finishing off the flat 90 deg face.

Cheers

Ron of Va
05-13-2012, 09:09 PM
I don’t have a photo of the tool, but it looks very similar to the one Dockrat showed in his post. It has been over a year since I took those photos, I am not sure exactly which one I used.

Yes, I cut towards the headstock, until I think the waist is the proper diameter. Stainless baffles can be a little thinner than aluminum. Those baffles are for a 22lr.

After I part it off, I flip it around and put it into a homemade collet to finish off the cone on the other end. For the mouse holes, I use a 5C collet, and at the time, I was using a milling attachment on my lathe. (I have since obtained a milling machine.)
Here are the other photos.

http://www.hunt101.com/data/500/medium/Group10-19_150_.jpg

Some of those baffles went into an integral 10/22 I made. You can see it here.
http://bbs.homeshopmachinist.net/showthread.php?t=35021