Screw cutting query

[Eric CoxParticipant @ericcox50497]

I've noticed on a few forum postings that mention is made of setting the compound/top slide at an angle when screw cutting.

This is something I've never been taught to do nor ever have. I just grind the tool profile to the correct angle and use the cross slide to feed the tool in.

Why offset the compound slide.

[Eric CoxParticipant @ericcox50497]

[John Stevenson 1Participant @johnstevenson1]

Really comes into it's own when doing large threads as setting at an angle means the cut is all on one side instead of both and reduces the stress on the machine.

There are definite thoughts on whether you should do this, a bit like religion and knurling but a lot is machine dependant.

Anyone with a rigid machine can get away with either. Like a lot of processes in this hobby / trade, there are a 1000 ways to do things, none incorrect but all different.

[jason udallParticipant @jasonudall57142]

The Cross slide is used to advance the tool in depth. ..and longitudinal motion is provided by the lead screw. ..that much is obvious. ..the half angle offset is an attempt to cut on one face of the vee tool only
..for some this reduces chatter. .

[Martin KyteParticipant @martinkyte99762]

You can use top rake with set over top slide too.

Martin

[BazyleParticipant @bazyle]

Lots of forum threads you can read where people drone on about their favourite way, be it "plunge cutting" or "setover", being the best. For some the main issue is not wanting to move the topside off parallel as they do all their turning with it.

I suggest, if this is the first tiime you have heard of the method, you should consider getting one of the beginners books eg Ian Bradley "the Amateur Workshop" as there must be a lot of other stuff you don't know about. Also some of Harrold Hall's books probably cover it.

[MICHAEL WILLIAMSParticipant @michaelwilliams41215]

An alternative method is to leave the topslide in its normal 90 deg to cross slide position and then to advance the topslide a little every time you increase the cutting depth with the cross slide .

Topslide advance can be a calculated amount if you wish but just as easy to do intuitively after a couple of goes .

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