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Recommendation for Boring Head for Brother Speedio?


Feb 19, 2017
Los Altos
Looking for recommendation for highest quality boring head for my Brother Speedio, I've got dual contact BT30 spindle 16K.
I've used the Iscar ITSBore, that's a popular one, been around for years.
We currently have a Sandvik head that we use on 1 repeat job boring dowel holes to hold .3745/.3748" diameter and even after 100 holes in 4150pht it still cuts on size. Set it and forget it.
Once I discovered Devlieg Microbore inserts and bars ? Except for a size I didn't have and couldn't wait, the boring head fell by the wayside. Good to have one but the microbore inserts work so much better.

There's a few outfits making similar boring cartridges to Devlieg stuff.

Rigidity is terrible with a boring head. Boring cartridges are rock solid.

I've got 20+ Devlieg bars including a half dozen integral 50 taper bars. They do HBM stuff nothing else can do.

I also use them in the CNC's to bore down to 10mm.
Maybe I can learn something here. Where does the flex come from? The head itself or the bar in the head? The later I can readily understand if the bar is longish.
Like @Garwood said, the adjustment mechanism is what creates the slop, in a boring head you have the moment arm of the bar leveraging against that slop which can cause instability. With a cartridge system there is no lever arm to put a moment load into the adjustment mechanism making them much more stable.
Thanks! Makes sense. The ways on a boring head are very short. Any give in them would be amplified.
I've used the ITS Bore heads for years, always liked them.

The lack of rigidity is a feature! I've used it to open up holes that were .0001" under where I knew if I tried to adjust the bar it would blow the hole out. SOOOoo, I increase the RPM and re-ran it so the centrifugal force slings the bar out juuuust enough to open the hole up to be in tolerance.
For the rare occasion I don't mill or ream to size, I use a Criterion TABH-250

1-1/2"-18 Thread Back Tenth Adjusting Boring Head Boring Head.​

just set it up earlier today and had my squint just right and nailed it on size first try.