[bob1112]

I am at quite a cross roads with our lathe work on our Mori slant bed. We are still way under tooled. Mostly because I don't have 6 months to learn it all or have the desire to spend 10K on a tool rep to tell me "what I need". We have a few VMCs and though many say lathe work is easy, I agree the "work" may be easy, but the tooling is anything but...

We use WNMG inserts in 432 right now, and basic GTR/GTL -2/-3 inserts and blades for part off. The WNMG works great. I am using high polished TMX inserts for Al and TMX coated inserts for stainless. The 432 is probably not the right radius for finishing but has been reasonably durable.

Part off is our number 1 problem right now. It has been unpredictable, finish sucks, sounds bad, eats inserts, you name it. Al or SS. Some say the inserts and blades suck but without knowing why, I am not excited to throw bucks in a hole hoping it will fill in. I was originally looking for a parting insert, with inch clamp, that could part and turn a bit. I was told before that due to the expense of those suckers, you want a go-to for parting and use it only for that.

I was told the center is off, blade not straight, you name it, the GT2 and GT3 blades just will not cut right. They make really nice watch springs but the finish is bad on the part, tolerance is out, and tends to make a taper or radius sometimes on a flat cutoff.


Moving to threading, it seems there are a couple main designs out there. The triangle insert, and the long skinny. Not real sure which is really better but I do like how the long/skinny also comes in other geometries.


All in all, I am trying to get a handle on OD/ID tooling, thread tooling, and find a solution to my parting problems. Probably too much for one post but I will try. I am trying to stay more with ISO or standardized tooling so I can buy one guy's holder and another's inserts. I probably need a smaller and finer OD tool and I have even resorted to sticking an old endmill in the lathe to get some ID work done!! Friggin worked great and held .0002 but not ideal.

Machine is 1.625 bar cap and we rarely do chuck work with it. Most parts will be intricate and small. Oring lands, back cuts, conular face cuts, etc. The only thing I don't like about solid carbs is the cost to retool on breakage but I suppose some of this stuff must be done that way.

[txcncman]

The only way I have ever gotten consistently decent finishes for part off is not so much in the tool, but in the machining technique. Feed and peck. Make the peck increment equal to the feed. Usually 0.002" works ok. Maybe as high as 0.008" on aluminum.

Triangle threading inserts give you 3 corners. You can calculate the cost yourself.

Rough with 0.032 radius. Finish with 0.015 radius when possible. Yeah, means you have to run 2 tools.

The best tools to run are highly dependent on your machines and your parts. Yeah, that means trial and error.

Some of the solid carbide tools for smaller ID work can be resharpened (if you have a keen eye and steady hand). Usually a crash hard enough to break your carbide will pretty much ruin an inserted tool holder too.

You get what you pay for.

[bob1112]

Any thoughts on brands or lines that offer a good value? Iscar and Sanvik seem to lead the pack but I have been looking at some Kaiser thinbit tooling. Price might make me run for the hills but looks like good stuff.

[txcncman]

Well, a lot of Iscar's stuff is proprietary inserts. You had said you wanted to avoid that. But I do like Iscar's deep grooving OD tool for the type of work you described. They work very well for both grooving and part off. I am not as familiar with current lathe tooling option. I have been doing mainly mill work for the last 7 years.

[fizzissist]

I've been using the WNMG inserts for years, and really like them. Like txcncman recommends, I've also been roughing with the 432, and finishing with a 431.
In contrast to the CNMG, I like the 6 edges you get vs. the 4 functional... unless you have a dedicated facing tool that can use the other 4 corners. For my jobs, I find it more efficient overall to just use the WNMG tools for facing and not lose a position for an extra facing tool.

I've used Sandvik extensively for years (the company gave us excellent prices and support), and have been playing with Mitsubishi recently. I like the Mits so far, but don't have enough quantitative data/history to say anything really meaningful... But friends in other companies swear by them. I've used Iscar too and like their stuff, but again, not enough history.

For the cutoff side of life, it really is trial and error. I've had parts come out with great finishes, then every 5th part sucks. Or 9th part. Or all the parts. Pecking with short steps is most often the only thing you can do. That, and play with insert geometry.

I highly recommend standardizing on inserts, if for no other reason, the tip radius will be more consistent, you can use qualified tooling, and you can develop tool life planning. I don't think cheap inserts are cheap. After all, if I see the tip start to show excessive wear and I can swap out with a fresh insert and push the green button in less than a couple of minutes... I'm happy not having to bring down the tool eye or take a test cut.

The end mill thing? I hate doing that.. but it does work, and it's a great place for those endmills that still have one good corner!

Boring bars are my nemesis. For example, I've got a 3/8 shank bar rated for 4xDia, and that's my part length... On the margin, right? Nope. Ringin' like a big dog. It seems that the actual clamping is 1/4" back from the face of the bushing, so the effective overhang is pushing 5x... I shoved toothpicks in between the shank flats and the bushing bore. Seems to work. And cheaper than the proper solid carbide bar I should have. :cheers:

The other thing about boring bars is getting coolant to the tip with the little ones.. I hate grinding notches in bushings.

[bob1112]

I appreciate the responses. Sounds like my goal of try to use mostly standard tooling is appropriate. However, I realize some cuts are special and require special tooling.


It sounds like many brands make good tooling so is it appropriate to ask who makes great tooling but priced right? I know we have a TMX hogger face mill modelled similar to a Mits cutter. Super great cutter! Not sure sure how much cheaper it is though.

[txcncman]

Travers Tool markets some of their own branded inserts and inserted tools that you may find cost effective.