Parting tools and inserts

[Henry BrownParticipant @henrybrown95529]

Posted by Tony Pratt 1 on 24/02/2022 11:31:33:

Posted by DMB on 24/02/2022 11:09:28:

I looked at PeWe parting toolholder and my bad language exclamation is unpublishable-is it gold plated? €85 = £68 approx. No way!

In my description above, I forgot to mention my toolholder has a clamp plate forcing the HSS blade tightly in position by tapers and I think, 3 caphead screws. Blade thickest I could get – about 3/32" to resist side – bending. As I said, works perfectly, happy boy!

Vaguely recall that it cost around £20-25.

And that is why everyone buys cheap Chinese crap, me included, it's hard to resist PeWe I presume is made/shipped from Germany but is it also made in China?

Tony

Tony, the PeWe kit is made in China by a chap who has an engineering business in Germany, it is made to his specification and fully interchangeable with the original brand.

I have spent most of my working life in precision engineering and have been very impressed by his service and the quality of the tooling I received. Old, old story, buy cheep get crap – the Chineese will provide quality but as all things it comes at a price.

[Tony Pratt 1Participant @tonypratt1]

Posted by DMB on 24/02/2022 12:08:33:

I agree with you,Tony. See my one and only album photo, to view type of holder. I have just tried websites to find it for sale – no luck so far –

Arceuro, Reeves, Axminster, RDG tools, Rotagrip, Warco, Chronos.

John

Thats strange you have a 'Dickson' style tool holder, they should be readily available. Update, found them on RDG website, not sure about sizes though.

Tony

Edited By Tony Pratt 1 on 24/02/2022 12:49:09

[Clive FosterParticipant @clivefoster55965]

When it comes to parting off inserts and holders its best to use the same make of inserts and blade. Tolerances and shape of the gripping region are very tight so generic inserts may not fit quite well enough for long life or reliable holding.

Insert should be stronger than the blade. I've snapped the hold down tongue off a Kennametal blade. Insert was still serviceable. 15 years and counting has gotten halfway through my first 10 pack of inserts and onto my second blade,

As ever with parting off its rigidity, rigidity, rigidity that matters along with feeding dead square. My Dickson QC toolposts live dead square to the lathe centre line so no set-up issues. I have a cunning plan for rapidly resetting square should I ever move the toolpost or adjust topslide angle. Would be unsurprised to discover that a major reason for folk getting better results with a rear toolpost is simply that its worth spending the time to get it dead right and, once its right it stays right. Swopping tools around its tempting to accept close, very close which may not be close enough this time rather than take the extra time to get it just so. Getting just so really needs test cuts too. Impractical mid job. QC toolposts should make swopping relaible but they have been known to move a touch during a job.

I tend to run insert tooling at normal HSS turning tooling speeds and HSS blades at half to 2/3 rds HSS turning speeds. Almost invariably with spray lube to help the chips get out. Even the folded chips from an insert, which are narrower than the slot can get stuck up. Running at higher speeds makes it easier to keep the chips thin and flexible for easy escape. Hand feeding whilst grinding along in back gear is a serious exercise in patience and thick, inflexible chips are almost certain. Not good.

If you have a Dickson style holder, like DMB, make sure your blades have the correct bevels to match the holder on them. Allegedly some of the inexpensive sources of both blade and holder are bit sloppy in both the angle of the bottom lip and that of the body the tool sits against. Tolerances are deceptively strict to ensure that the blade doesn't pop out and sits with clearance both sides. Thats why they are expensive and rarer than the other styles.

Relatively easy to make a new top (gripping) wedge for Dickson holders to take blades of next size down if you luck into a wrong size stash. I have T2 size holders and did so after a 5 blades for £5 bargain turned out not to be deep enough! 15 years and counting on the first blade.

Clive

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