Parting off alluminium

+1 for faster, with a big lump of ally you ideally want to speed up as you go in AND increase the feedrate to match.

A sure fired way to get more friction = more heat = melts the al and it sticks. That's the problem.

Also not keeping and even feed, more or less stopping which causes the tool to rub. So just like more speed = more heat.

John

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Edited By Ajohnw on 06/01/2017 23:35:36

Since I was given a demonstration of Iscar insert parting tools when they first came out, I use them in rear toolpost upside down and engage the crossfeed at a reason speed with plenty of suds. This clears the swarf which cause the heat build up and the sticking.

The suds don't cool it all then. I thought that was why suds was regarded as a coolant.

John

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I've contrived an attachment which solves the problem of tool jamming, just wait for some monthes as this attachment will be described in MEW.
J Maurel

I will look forward to seeing the attachment Jacques, Always something new to learn, until then it is the rear tool post and lube for me. Just parted 40mm diameter at 1100 revs and 0.05mm per rev feed. Squirt bottle of suds to cool/lube.

I find the word jamming a bit odd. Can't say I have ever had it jam just noticed that the tool isn't cutting well any more. That's been with HSS and I suspect means I should have touched the blade up with a stone.

When I first started using raked tip inserts they were coated for stainless. I was surprised how quickly al rubbed the coating off. It might be best to try general purpose for parting off if nothing else is available.

I bought a tipped blade and holder just before my workshop packed up. The one from RDG. Myford qctp fitting with a power bulge to take 1" deep blades. The holder looks to be ok but the blade is a bit shoddily made. It has a bit of taper which goes the wrong way. I suspect it should be parallel. The tip is tiny and obscure too. No point buying a proper one until my workshop is up and running again.

I have snapped of a 1/16x1/2 HSS blade that needed to have about 2" sticking out. I put that down to me. To fast a hand feed as I was in a rush.

John

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If you are parting off a large diameter don't try and do it in one go. Feed the tool in so far then retract the tool and move it across about 1mm and feed in again. Keep doing this and the tool won't jam. Also make sure the tool and holder is at right angles to the work piece.

I cut at a slow speed as far as I can until I notice the first signs of sticking then back right out and take another cut to one side slightly less than the tool's cutting width thus having a wider cut. Return tool to original position and continue cutting which it will now do without sticking. Usually once is enough on say a 2" diameter piece but might need to do same again on a much larger diameter. Takes longer to explain than do it

(Edit: Having typed that I now see Eric does the same! )

Having taken on board the advice given I did some more parting of aluminium and all went well, so thanks guys