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View Full Version : How to best cut with horizontal mill?



Steve Steven
02-02-2009, 07:55 AM
I have a Van Norman #12 mill, I mostly use it as a vertical mill. However, I have a large piece of A-36 steel (4 X 10 X 1/2 X 12" long unequal leg angle) than I need to cut down to 3 X 4 X 12. I just finished cutting off the 1" from the short leg, I now need to cut the 10" dim to 4". I made this cut using it as a horizontal using my 12 X 1" homemade bar. I have a 4X6 bandsaw, but this piece is too big to get on the saw table.

I did the first cut with a 6"dia X 1/2" wheel cutter, it went OK but a bit slow. Cut in 0.060" bites at 140 rpm and 2" feed, chips smoked a bit (using oil) but did not discolor, wheel runs out a bit.

Wondering how to best make the cut to cut off the excess on the 10" dim. I have a 4" X 1/8" cutter and a 6" X 1/4" one. How is the best way to do this?

I could cut in one big bite, with a slow feed, or a number of small bites at a rapid feed. Which way is the best? Which cutter is the best one to use? I currently have the 4" X 1/8" one on, it is a side cutting type and brand new.

Any comments are welcome.

Thanks,

Steve

joeby
02-02-2009, 12:41 PM
I'm not sure if I understand your setup. You are using the cutter on something like a slitter saw arbor?

Kevin

pcarpenter
02-02-2009, 12:51 PM
Get yourself a big slotting saw (the kind with teeth on the side). IF I read the description well, you are trying to slice off a piece of a big slab.

This sort of cutter is designed for the job, but you must have the type with teeth on the side or it will grab. It may grab anyway, but the side cutting teeth will help.

It sounds like you are doing the same with a 1/2" wide cutter...but that has to remove a lot of material to get the job done.

Paul

Roy Andrews
02-02-2009, 12:58 PM
i know this is going to seem smart ass-ed but in the future cut the 10" side down to 3" and be done. but in regards to your question i usually take multiple small bites as i have been told by a competent machinist. his view is it causes less stress. as far as your wheel cutter running out i think thats the rule rather than the exception as i have quite a few of them and they ALL run out ring, ring, ring, as they cut. i was using three of them yesterday and my son was trying to help and changed over from the 2" 1/16 to the 6" 3/16 to make the next cut and didn't change the speed. i was running the 2" near max, the 6" lasted about 1". anyone want a fairly dull slitting saw?

Steve Steven
02-02-2009, 01:18 PM
Thanks for the help guys. In answer to your questions,

Joeby, yes I am using a slitting saw on an arbor in horizontal mode.

Pcarpenter, Yes I have several slitting saws, the kind with teeth on the sides. One is a 4" by 1/8" that will have a smaller kerf, the other is a 6" by 1/4" that will have a larger kerf. I had a few instances of the saw slipping on the arbor, since I don't have a key slot in it.

Roy, I don't know why I didn't think of that! You are right of course, I was misled by what I had been doing in the past. I think you are right in doing small cuts and doing several of them.

Thanks for the comments, keep them coming!

Steve

derekm
02-02-2009, 01:33 PM
you are basically trying to saw 1/2" steel - doable with 4" x 1/8"
(allowing for clamp clearance)
Use flood coolant (water based is best for heat removal) and the correct speed ( My info suggests 50 ~130 rpm).

I'd find a way of putting a keyway in that arbour if it was mine. e.g. make a second arbour so you can put key ways in both.

Steve Steven
02-02-2009, 10:04 PM
Well,
I cut it tonight using the 4" X 1/8" slitting saw. I started with 0.040" deep cut, 76 RPM and 2"/min feed, ended up with 100Rpm 0.075" deep cut and 2"/min feed. At that cut, it sounded like it was working but didn't have any cutter slip and worked well, didn't throw any hot chips and very little smoke.

BTW, I was wrong on the RPM I had previously quoted for the 6" X 1/2" slitting saw, the actual RPM was 76RPM.

Thanks for the help, the job is going well.

Steve