Insert tooling -- strategy

[durableoreo]

I'm trying to figure out insert tooling for my 9x20. There are so many choices. Would you help me reduce the degrees of freedom? For purchasing insert holders, Is it enough to choose a shape and size? Does brand matter for the insert holder? Should I pick a brand, such as Sumitomo, and buy everything from them? Or is there some other company or strategy I should consider?

 

[OCJohn]

I'm not very invested in insert tools, so I'm always interested to read relevant advice. That said, I haven't spotted much consistency. But just a few days ago I was flipping through Tom Lipton's book and found this cogent gem:

Always have an insert turning tool set up in a tool block for general purpose work if different people use the machine. CCMT or WNMG inserts are a good compromise. You can switch insert geometry easily for different materials. WNMG gives you six cutting edges per insert for good economy. We set ours up with the thought of one optimized for harder materials and one optimized for softer materials.

 

[Rex Walters]

Probably not the answer you were looking for Definitely not the question you asked, but for hobbyists on a budget like myself, HSS and brazed carbide tooling can take you an awfully long way, and learning to grind your own tools for different materials and situations can take out a lot of the mystery around carbide insert geometry.

One tip that I was recently turned onto: offshore CBN wheels for a bench grinder have gotten shockingly cheap and make shaping HSS tooling MUCH, much quicker and easier (the tool barely gets warm and material comes off FAST). Use the CBN wheel to shape the cutter, then hone on cheap bench stones.

Brazed cutters last longer, but they are a lot slower and messier to grind on a green wheel.

 

[OCJohn]

Probably not the answer you were looking for, but for hobbyists on a budget like myself, HSS and brazed carbide tooling can take you an awfully long way...

That's why I haven't gotten into inserts much. I've picked up enough HSS and brazed stuff at auctions and estate sales to last me a lifetime.

re CBN, can those wheels be used on brazed carbide without damage to the wheel?

 

[Rex Walters]

re CBN, can those wheels be used on brazed carbide without damage to the wheel?

I don't think they would do much on carbide (green wheel or diamond for carbide). I'm spoiled with a Glendo slow-speed grinder and several diamond wheels.

Out of curiosity, if you've got grinding/honing down, what's driving you to investigate insert tooling?

 

[OCJohn]

I didn't say I have it down. I just have a lot of it. And who doesn't want more tools?

Back to the OP, you got me looking up info and I found a handy insert chart at Carbide Depot: https://www.carbidedepot.com/formulas-insert-shape.htm

 

[G-ManBart]

I'm trying to figure out insert tooling for my 9x20. There are so many choices. Would you help me reduce the degrees of freedom? For purchasing insert holders, Is it enough to choose a shape and size? Does brand matter for the insert holder? Should I pick a brand, such as Sumitomo, and buy everything from them? Or is there some other company or strategy I should consider?

I don't think the brand of the holder, or the insert really makes much difference for hobby use, on hobby machines where the speeds are quite low and there isn't a need to maximize efficiency. The cheap, imported tool holders direct from China on eBay, from Amazon, or places like AliExpress work just fine as do the inserts. What I do is buy a pack of inserts with a holder and if I like their inserts, buy a bunch of them the next time I order something.

For smaller machines stick to an insert with positive rake. CCMT, TCMT and DCMT insert styles would probably cover 99% of most facing, turning and boring. In many cases you can find both turning/facing and boring holders that use the same inserts, so that helps cut down on the total number of insert styles you need to keep on hand.

A kit like this will set you up for turning, facing and boring for very little money.

4pcs 12mm CNC Lathe Turning Tool Holder Boring Bar CCMT09T304Carbide Inserts Set | eBay

4pcs T15 wrenches. 1 SCLCL1212H09.

www.ebay.com

 

[benmychree]

I like TPU or TPG inserts for nearly all I do, counting potential cutting edges is foolish, in my opinion.

 

[Rex Walters]

I like TPU or TPG inserts for nearly all I do

Amazingly, I actually have a few tools that use triangular TPx inserts.

John: You know how much I trust your judgement, and the kind of work I do (AKA "hobbyist goofing around making one-off parts"). Is there any reason to worry about the tolerance difference between TPG (ground) vs. TPU (utility) inserts? Or am I okay with my standard "cheaper == better" strategy.

 

[Rex Walters]

I found a handy insert chart at Carbide Depot

Wow is that GIF is unreadable if you've configured a dark color scheme on HM! Fortunately (?), if you follow the link, "dark" mode is ignored (making it readable).