Steel tubes

[Stoneair666]

I get an order for about 50 tubes every month... Cold roll steel 2.5" dia. Anyways i need to make two 2.000" holes in it. It's only .250" thick. Now the machinist before before had made the program, and everytime the job comes by they say just load the old program... Well he programmed a 1.000' 4flute end-mill to plunge into the piece, then he takes a .500" 4 flute endmill to make the hole... the machine rumbles when the cutter goes into the tube, and i was thought 4 flutes don't plunge.... but it worked for him, but always hid the damaged end-mills... after cleaning the machine area i found a lot of mistakes he made over the years with a lot of tooling.... Ever though i knew it was wrong i ordered another endmill only because i said center-cutting... anyways either the night guy chipped it or it happened when it was plunging but 100 pcs later my new endmill is chipped I've thought of some tools for the job, but still don't really think it's the most efficent way....


Anyone have any ideas on how to cut this 2"dia. hole into a .25" thick steel tube quick and without breaking anything?

[JPMach]

Use a carbide insert drill to punch the hole in then clean up with endmill.
Ingersoll makes a nice quad drill get one around 1 3/4" or so, Provided the machine can handle it. They are expensive at first but inserts are only around $12.00 each and have four edges on them. If the hole has a decent tolerance on it just get a 2 inch drill and boom. Ingersoll's mid range sugested speed for steel is around 3000 rpm for a 1.25 drill (thats what I have).

JP

[WhiteTiger]

Rotabroach

Bit pricey but just the tool for the job (imo). Sort of a multitooth trepanning cutter.


Tiger

[Stoneair666]

thats exactly what i was looking at, inserted cutters... but i was thinking of a 1.5" -1.75" center-cutting endmill but i like the drill idea better i didn't think of it even though it's in my catalougue.... Thanks

[JPMach]

I believe Ingersoll is has a sale on the quad drills right now. I looked at their site an under promos it says the 1.75 in a 2:1 length is $410, Same price for a 2" also.
JP

[JPMach]

And thats with 10 inserts, spare screws and a wrench.

JP