Issue with parting on a 7 x 12 lathe

[RJD]

I am having a problem separating the spool plate from the front ring utilizing a 7 x 12 lathe in terms of achieving desirable results. The material is .064" aluminum that is screwed through the center as well as via the pillar holes to a mandrel. The method attempted involved using a narrow parting tool (.040) with the top of the tool on the center line of the lathe, a low speed (approximately 200-300 RPMs), tool perpendicular to workpiece, cutting fluid, and a slow/steady advance of the tool. However, the pieces look like the parting tool cut at an angle. I assume this is a function of my rather limited lathe experience. Any suggestions? Thanks.



Ron

[432taylor]

sir
grind the parting tool 1/8 wide a 1/2 inch into the parting tool
hope you know what i mean if not call me at 201-489-9348

[RJD]

The following link contains the parting tool used. In addition to my aforementioned information, there was just enough of the tool exposed beyond the tool holder to make the cut to eliminate the possibility of it flexing thus distorting the cut. It was selected because it was narrow enough to separate the pieces without cutting to much of the spool plate away thus rendering it unusable.

http://www.littlemachineshop.com/produc ... &category=

Ron

[Stan]

RJD
From the picture it looks like these parting tools are made for parting off in the traditional from the outside of the component towards the centre of the component ie. at a right angle to the part. You might find that because the tool was used for what we call trepanning or face grooving that the bottom of the tool might have been rubbing on the inside of the part you were trying to cut? To get around this you could just use a standard piece of H.S.S. and grind it to the required width but give it plenty of clearance on the bottom of the tool. Or you might be able to grind the bottom of the tool you used so that it doesnt rub on the inner part of the job?
I hope this makes sense? Without seeing the component I may be incorrect in my assumption as well?

Regards
Stan

[Thunderbolt]

Ron, I had the same problem when doing my alum. reel. The outside face of the parting tool does not have enough clearance and will be pushed in towards the centre of the plate as you advance towards the head. Try grinding the outside face of the parting tool, thats the left hand side as you look from tail towards chuck, with lots of relief to fit in the circular groove you are cutting. Its the bottom outside edge of the parting tool that is causing the grief. Also reduce the width of the tool as much as you are game and also reduce the nose depth to minimum . You may also be able to lift your parting tool about 0.020 or 0.030"..that might reqire a bit of trial and error testing though. I ground my own tool as Stan suggested
I'm a self taught machinist with minimum experience so this may be of no use to you
Cheers
Cliff