Thread: Diamond shaped insert tools

I have Pete.

Originally Posted by Pete F

Rather than hijack Ken's thread I thought I'd better start another. I notice CNC lathes often use narrow diamond shaped insert tools (60 degrees??). I wonder if anyone has used these same tools on manual machines?

Pete

pete i have you can take big cuts because of the lenght of the of the leading edge. as well as that there handy because they have a little extra reach

CNC's use them as they are better for profiling but there not really designed for heavy roughing, where a square insert or triangle one is a bit more solid.

Ok, thanks guys. Apart from not really being designed for heavy cuts, are there other disadvantages with this style on a manual lathe? I'm happy to tone down the cutting if they provided definite advantages in other areas. Worth pursuing?

Pete,

I bought the little toolholder because other than it being brand new and cheap, it was small and left handed. It is real handy for undercutting shoulders and for working close to a live (or dead) centre.

Bob.

One problem with those inserts is they are very brittle and expensive with only two edges per insert...

But the ones I have leave a great finish and are great for profiling...

ya 2 edges does suck. and the guy at the market doesn't have that type of insert.
the tool i use the most is a trigon or w shape. which i think is a good all round tool.
my diamond or rhoombic 36 deg. is very handy but doesnt get as much use because i only have a few inserts. the trigon has 6 cutting edges and are easy to find cheap. both tools work for facing which is good as well

As a follow up, I bought one of the holders, made in Taiwan but with Swiss made inserts and have been extremely impressed with the finish. I'm using it on a Hercus and the photos show it running it at maximum speed cutting steel with 0.5 mm depth of cut. Again more crappy photos but hopefully you can get the idea.





Taiwan Tools:Tooling System/Cutting Tools-Turning Lathe Tool Holder,OD Turning Tool Holder,CNC Tooling system cutting tools,Collet Chuck Boring Bar,Milling Cutter,Lathe turning tool holder

Inserts are from Lamina
Lamina

Pete

If a negligee was in sight, I would have sworn David Hamilton was the photographer

What is the steel? Girly 1214 or manly 4140? Nice looking finish though, Pete.

What is the exact specification of both the holder and the insert?

BT

Pete,

How did you get on buying from Taiwan Tools?

I was going to purchase a saw arbor from them at Christmas time but was put off when they wanted payment up front for an item that had a production lead time of six weeks. I know Eskimo has bought gear from them without any problems.

Bob.

Bob, the steel was an alloy of scrapoli/noideari 90210. I was just making up a little expanding arbour to hold something. Also same material to quickly make up a tool centring jig. I was going to make up a gauge, but have a bit too much to do at present and quite busy, so this will do for now. Another photographic masterpiece for your viewing pleasure



I didn't deal directly with the company, bought from a retailer in Hong Kong. As far as specs, I'm afraid the link is as much as I know about it, but I'll definitely be tracking down more of those Lamina inserts. I swapped that tool for some other CDCO insert tools I have and the difference was like night and day.

Pete

Edit: Ok that was an especially crap photo, sorry for that. If you're still trying to work out what the heck it is, it's simply some round scrap turned down to 18.00 for no particular reason than the fact I screwed up 20.00 by 0.01 mm and couldn't live with myself if I left it undersize and somebody broke into the workshop in the middle of the night and measured it. Milled a flat exactly half way through it. Chuck it in a collet or chuck and centre the tools off the flat.

Noideari can be a problem alloy, best avoided unless being used for lesser, mundane tasks. 1214 is easy to identify, more often than not by the sheen of telltate rust. I have a problem achieving a nice finish on 4140, unless it's a heavy cut, say 2-3mm.

The Swiss inserts should have a code on the box ( if you bought a boxful ).

Is the flycut table that of the No. O?

BT

Milled a flat exactly half way through it. Chuck it in a collet or chuck and centre the tools off the flat.

Only if it is horizontal.

It's quite easy to tell if it's horizontal by running the tool across it and looking at the gap, alternatively simply put the tool in the centre of the jig and it can be way off horizontal and it doesn't make any difference for all practical purposes. A good reason to leave the light machining marks from facing the piece off.

Rather frustratingly I was just at the "I'll give it just one more turn" of the tapping stage, when one of my "amazing value" Indian taps snapped off.


Pete