friction cutting metal on bandsaw

About 15 years ago I was visiting the shop of an old fellow who rebuilt
shop machinery, who is no longer with us. We started talking about metal
cutting bandsaws, and I didn't see one in his shop so I asked him why.
He picked up an old file and walked over to what I thought was a
woodcutting bandsaw--and with sparks flying, ripped right through it in
less than ten seconds.
Can't remember what kind of blade he used, whether it was bimetal or
carbon but I do remember that the blade tension was very high, as was
the speed. Anyone use this friction cutting method for metal?
Ken Grunke
Reply to
Ken G.
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You have to have really high speeds. Wood cutting is like 3kfpm, I think friction sawing is at least 5kfpm up to 15kfpm. No way my saw could go that fast. - GWE
Ken G. wrote:
> About 15 years ago I was visiting the shop of an old fellow who rebuilt > shop machinery, who is no longer with us. We started talking about metal > cutting bandsaws, and I didn't see one in his shop so I asked him why. > He picked up an old file and walked over to what I thought was a > woodcutting bandsaw--and with sparks flying, ripped right through it in > less than ten seconds. > Can't remember what kind of blade he used, whether it was bimetal or > carbon but I do remember that the blade tension was very high, as was > the speed. Anyone use this friction cutting method for metal? > > Ken Grunke > > > >
Reply to
Grant Erwin
Though there are special friction blades, any blade will work. I use dull 10 TPI X 1/2 carbon blades. The end of life for a friction is when the weld breaks. This can vary from annoying to frightening, depending on where the weld is when it breaks--I've had a few feet of blade fold up accordion style on the table. You learn to listen for the tic-tic-tic that warns of an impending break.
I can cut up to about 1/8 SS on my old DoAll which tops out at 1500 FPM, though more speed would make it go much quicker. When I was in the business of fabricating SS marine hardware I had a 36" saw that ran at 5000 to 6000 FPM. This would cut 1/4" SS efficiently and up to 3/4" in a pinch. The big dedicated friction saws run up to about 15000 FPM.
The process does generate some sparks, so be very careful friction sawing on a saw that's also used for flammable materials.
Ned Simmons
Reply to
Ned Simmons
Oh geez, I could have googled first and found all the answers from T-nut and others. I highly recommend googling in the groups, it's quite fun. I didn't know RCM and RCWoodturning went back to '94 and possibly earlier. There was also a noticable lack of OT posts in the early days, before everyone, their brother, sister, parents, kids, inlaws, etc had a computer. *sigh*
Ken Grunke
Reply to
Ken G.
I've friction cut quite a bit of 304, 316 and mild steel sheet (up to 1/8") on my 14" Rockwell/Delta bandsaw at ~3000sfpm. A 24-32 tpi blade installed backwards works pretty well, but you do need to "lean into" the piece to be cut. In a like manner a steel blade installed backwards in a skil saw does a good job on galvanized roofing.
Reply to
Jim Levie
[ ... ]
Yep -- back when people knew what netiquette was, and honored it.
BTW You can download all of the past traffic in rec.crafts.metalworking on a one, two, or three file per year basis from the FAQ site which Scott Logan regularly posts pointers to. They are compressed with varying methods as time goes on.
I've uncompressed each, and recompressed with bz2, the current most efficient compressor common to unix, Windows, and I believe even Macs. Of course, that only affects the copies which I have downloaded. A couple of years ago if finally got larger than a single CD-ROM would hold, even with the best compression.
Beware that one year has several copies of one of the early virii included. (The whole process is automatic, with no filtering.)
Enjoy, DoN.
Reply to
DoN. Nichols
Jim - what does "sfpm" mean? ie, how does that term differ from "fpm"?
Hul
Jim Levie wrote: : : :> You have to have really high speeds. Wood cutting is like 3kfpm, I think :> friction sawing is at least 5kfpm up to 15kfpm. No way my saw could go :> that fast. - GWE :> : I've friction cut quite a bit of 304, 316 and mild steel sheet (up to : 1/8") on my 14" Rockwell/Delta bandsaw at ~3000sfpm. A 24-32 tpi blade : installed backwards works pretty well, but you do need to "lean into" the : piece to be cut. In a like manner a steel blade installed backwards in a : skil saw does a good job on galvanized roofing. :
Reply to
Hul Tytus
SFPM - Surface Feet Per Minute FPM - Feet Per Minute
six a one half a dozen of the other ..
GWE
Reply to
Grant Erwin
On Wed, 20 Oct 2004 16:26:02 -0500, Jim Levie vaguely proposed a theory ......and in reply I say!:
remove ns from my header address to reply via email
I must comment here. "Backwards" refers to tooth direction of travel, not which side of the blade the teeth are on! ***************************************************** Have you noticed that people always run from what they _need_ toward what they want?????
Reply to
Old Nick
Thanks Grant.
Grant Erw:> what does "sfpm" mean? ie, how does that term differ from "fpm"? : : SFPM - Surface Feet Per Minute : FPM - Feet Per Minute : : six a one half a dozen of the other .. : : GWE
Reply to
Hul Tytus

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