bandsawing steel stock - what am I doing wrong?

J

Jim Mass

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Hi,

This is my first post here besides my introductory. Over the past year, I've build up my workshop in order to supplement / compliment my business (consulting mechanical engineer). I've added a belt sander, vertical Jet 14" bandsaw, and a Grizzly G0704 mini-mill. I've worked several projects in aluminum, no problem at all, and the mill runs true and accurate after taking the time to calibrate and tram - loving the mill!
So, now on the the issue...
I'm working my first job in steel - some plates to be made in 1020 steel 1/2" thick. I bought some steel stock and also a bimetal bandsaw blade PN 4179A173 from McMaster.com, and was impressed to see the blade was made by Starrett when it arrived.
I went to cut the stock, put cutting oil on it, etc, and it didn't cut... period. I didn't pressure it into the blade, let it just let it take its time, but after about 4 minutes, I had cut into the plate about .030", and am sure the blade is now dull.
Thoughts? this was a 10-14 tooth variable pitch blade for 'hard metal' is stated on their website.

What's going wrong? Any advice is appreciated.

Thanks,
Jim
 
If that is the wood cutting band saw then it is running way to fast for the steel plate. A metal cutting bandsaw runs much slower than a wood saw.
 
What direction are the teeth pointing?
 
JimDawson said:
What direction are the teeth pointing?
Click to expand...

Good point!

It could also be that the blade tension is too low so it doesn't move as it should.

Some blade types are not meant to be lubed, this is worth checking to.
 
Jim,
1st check the teeth are pointing down.
2nd, check the RPM of the wheels and convert that to Feet/minute. You probably want about 100 FPM for 1/2" steel. If your 14" Jet = 14" wheels? then 27 RPM will get you close to 100 FPM. A lot slower than most hobby bandsaws run.
3rd, Although coarse, a 10-14 TPI blade is still pretty fine for 1/2" steel. If you plan on cutting a lot of that thickness, look for a 4 to 6 TPI blade or maybe 8 TPI tops

Cheers Phil
 
I use the Starrett bi-metal blades from McMaster-Carr in my portaband, and they hold up real well. I don't use cutting oil on with the bandsaw. . . . Maybe the oil isn't helping you?

Jim
 
Jim Mass said:
Hi,

This is my first post here besides my introductory. Over the past year, I've build up my workshop in order to supplement / compliment my business (consulting mechanical engineer). I've added a belt sander, vertical Jet 14" bandsaw, and a Grizzly G0704 mini-mill. I've worked several projects in aluminum, no problem at all, and the mill runs true and accurate after taking the time to calibrate and tram - loving the mill!
So, now on the the issue...
I'm working my first job in steel - some plates to be made in 1020 steel 1/2" thick. I bought some steel stock and also a bimetal bandsaw blade PN 4179A173 from McMaster.com, and was impressed to see the blade was made by Starrett when it arrived.
I went to cut the stock, put cutting oil on it, etc, and it didn't cut... period. I didn't pressure it into the blade, let it just let it take its time, but after about 4 minutes, I had cut into the plate about .030", and am sure the blade is now dull.
Thoughts? this was a 10-14 tooth variable pitch blade for 'hard metal' is stated on their website.

What's going wrong? Any advice is appreciated.

Thanks,
Jim
Click to expand...

Try cutting without lubrication. I used lubrication when cutting aluminum.
 
As was said, its a wood saw and youll have to reduce the speed a lot. I put a triple reduction on mime (jackshaft) and now it cuts steel great. I have the formula, pulley sizes, pics, but not right now on tablet.
 
A good range for a metal cutting bandsaw would be to aim for 70-300 FPM
Hard steels, or thick stock, low end of range. Softer alloys and brasses, higher end of range. Aluminium can be cut faster than that but it just makes the reduction more difficult to set up.
Basic math will get you there. Dia of wheel (in inches) x Pi divide by 12, gets you feet per revolution.

Cheers Phil
 
Everything else has been covered. My Hardinge lathe starts up so fast,I once wasn't paying attention,and started it backwards. The metal was spinning so fast,I couldn't tell the rotation direction. Then,I wondered why I couldn't get the tool to cut. Only momentary,but,stuff can happen,even after many years as a machinist!!:)

Your bandsaw needs to go 75 FPM to cut steel .
 
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