Discussion on all milling machines vertical & horizontal, including but not limited to Bridgeports, Hardinge, South Bend, Clausing, Van Norman, including imports.
A trepanning tool is something I've thought about purchasing....but I have no experience with one.
I'm thinking that I could save some time on some projects, like this one:
I drilled a 1-1/2" diameter hole, the biggest bit I have, and then bored to 2.375" with my 2" boring head.
I'm wondering though....how fast can one expect to cut a hole? Seems like chatter would be an issue, as all the tools I've seen have a rather large cutting face.
Also concerned with going thru more than one plate, like the above pic. (3 pieces 1/4" thick) I don't think that would work well when I got thru the first piece.
I have one of the Swiss made "Valcut" tools, but never really used it, as I went the CNC route right after I got it and from then on just interpolated bores .
As you can see, the geometry is interesting, which keeps it from chattering, as it "drags" the cutting tool.
It also has another longer "Arm" which allows for larger dia. bores, and left and right hand tool bits depending on which part you wanted, the plug or the bore.
It is amazing how well and fast it cuts, but the depth is limited. There may be longer cutters than what I have here available though.
I'd say that you could trepan that 2-3/8" hole in about the same time as it took you to drill it with a 1" drill.
It's pretty impressive!
Glenn
Operating machines is perfectly safe......until you forget how dangerous it really is!
I use BiMetal hole saws on the mill with flood coolant. 3 layers of 1/4 plate would be no problem. I'd cut it with a 2 1/4 hole saw then bore out to the final dia.
The Val-Cut is the one I was looking at. All the others I've seen appear pretty flimsy in comparison.
I didn't know that back angle was so extreme. Interesting.
Greg,
Dunno....I've never done very well with hole saws on thicker pieces. Granted, I've not used them in a knee mill....always in a drill press, mag drill, or hand drill.
What brand of hole saws do you use?
I like the idea of the Val-Cut. It uses a HSS cutter which I could grind & sharpen. Same can't be said if a bi-metal hole saw blade.
warmstrong1955 wrote:
I like the idea of the Val-Cut. It uses a HSS cutter which I could grind & sharpen. Same can't be said if a bi-metal hole saw blade.
Kinda' funky...
Cobalt, not square, and fairly critical on size so that they clamp properly.
Sorry for the blurry images.
Glenn
Operating machines is perfectly safe......until you forget how dangerous it really is!
warmstrong1955 wrote:
I like the idea of the Val-Cut. It uses a HSS cutter which I could grind & sharpen. Same can't be said if a bi-metal hole saw blade.
Kinda' funky...
Cobalt
Not a whole lot different than axial o-ring groove cutters I've made though.
The last ones I got were Morse, never heard of them but they seem to work fine, Starret seem to cut the closest to size, the others wobble a bit and cut oversize.
If cutting over 1/4 material drilling a hole at the edge of the saw cut to let the chips out helps a lot.
f350ca wrote:The last ones I got were Morse, never heard of them but they seem to work fine, Starret seem to cut the closest to size, the others wobble a bit and cut oversize.
If cutting over 1/4 material drilling a hole at the edge of the saw cut to let the chips out helps a lot.
Greg
I have some Milwaukee's...which seem better than many others I've picked up at a hardware store. (Vermont American for one)
I saw the Morse brand at Enco.com. No experience there.
I'll try one on a future project. Didn't think about a 'chip hole'. Good idea.
Lenox used to be available in different tooth configurations.
I have some with Bi-Metal variable teeth and a 3" hole saw with three teeth per inch. With 3 tpi, flood coolant, and a chip hole used on a Mill with back gear, it gets right after it!
Glenn
Operating machines is perfectly safe......until you forget how dangerous it really is!
I generally use hole saws when dealing with larger diameter holes. I've had several instances where I used a 6" hole saw in 1" thk 316 stainless plate. Takes a while and gets a little messy. Run the spindle as slow as it will go, lots of coolant, alternate that with compressed air to continually clear the chips.....but it will get you through the material.
If you are going to use the hole saw find a manufacturer that has a heavy duty or solid shank on the arbor. The light duty shanks will collapse and tear apart if the hole saw starts to bind.
