Need boring head recommendations

There seems to be quite a few straight-shank ones for sale on Ebay. I've favorited them so I can go back and have a look later. I may go this route unless I get a good reason why I shouldn't. My initial thought is that the straight shank shaft could spin in the R8 collet if I make a cut that is too heavy, but I tend to take lighter cuts with a large-radius tool spinning at a high rate of speed anyway.
I have a Rong-Fu clone mill, if that matters.
 
If I were to make an offer for that one , I would start at $200, settle on $220 no more, whether is that seller or any other, you still need to pay at least around that $200 to $250 for a used Criterion it seems, unfortunately the prices have jumped considerably compared to 4-5 years ago.
 
I am wondering how a Criterion head is superior to the boxed up kits all over eBay for way less?

i bought a 2” R8 kit, which was OK, and I later bought a 3”, which is much more substantial, and I’ve never gone back to the 2”. Now it collects dust. So I recommend going to a 3” from the start.
 
Winegrower said:
I am wondering how a Criterion head is superior to the boxed up kits all over eBay for way less?

i bought a 2” R8 kit, which was OK, and I later bought a 3”, which is much more substantial, and I’ve never gone back to the 2”. Now it collects dust. So I recommend going to a 3” from the start.
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I have a brand new Interstate clone of a Criterion DBL-202 and while it is a nice and functional head, the machining tolerances of the thing are not the same as a Criterion. Does it work? Yeah, it does but I much rather have my Criterion heads. Matter of taste and preference I guess.

Insofar as size, the DBL-303 is BIG and heavy. On a big, rigid mill this is not as big an issue but on a smaller mill like theRF-30 the OP has, centripetal forces are a big deal. Go too big or too fast and the mill will start walking across the shop. As always, go with what you need for the work you do. For me, I never need to bore bigger than 6" or so, so a 2" head is fine for me. I even prefer the DBL-202A that takes 3/8" bars so I can go faster before running into vibration issues.
 
If my knee mill has an R8 spindle (Bridgeport clone) is there any reason I would want to get a straight shank instead of a RB shank boring head? It seems like an R8 shank would be one less piece in the puzzle (no collet) and less likely to flex?
 
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ARC-170 said:
I'd like a decent boring head for my Rong-Fu clone mill. This one shown (Criterion DBL-202) is just under $200 shipped. It looks like the shank is welded to the head. Is this an issue? I have R8 collets, so it will fit just fine.

View attachment 422355 View attachment 422356

It looks fine otherwise. Thoughts?
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Did someone put a tig weld on there so the head doesn't unscrew from the shank if it were run backwards for some reason? Just guessing here.
 
great white said:
I’s be worried about that weld pulling something off center and causing excessive runout.

I’m no professional, but thats the first time I’ve seen a shank welded to the tooling. Seems kinda “buck shee” to me.

I’ve got somewhere around 60-70 cdn into my boring head with an r8 shank (all ebay bought) and it works just fine. I have no conplaints.
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??? Its a single point tool, even if it did "pull something off center", its a single point adjustable tool. It would not matter in the least bit.

Not as if a boring head tool is "on center" ever anyways. And that is the point and why its accurate. The spindle itself generates the cyclinder and does not rely on the accuracy of the tool itself like drills, end mills, and to a certain extent reamers are.
 
MikeInOr said:
Did someone put a tig weld on there so the head doesn't unscrew from the shank if it were run backwards for some reason? Just guessing here.
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Yes, that seems to be the likely reason.
 
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