cutting 2" carbon steel pulley stock

see my post to this question on alt.rec.hovercraft
John wrote:

Thanks Robert.
For anyone else that might have some information to offer here, I'll clarify a few things...
The material was described as carbon steel by the supplier. Not sure of the exact composition. I'm actually trying to slice 20mm wide sections from a 200mm piece of stock. The sections are then faced and bored on a lathe.
I've previously done 20 tooth stock with no problems but this larger 28 tooth stock is wrecking the band saw blades after only cutting a part or two.
John

Why don't you just purchase 2 inch steel blanks flame cut to your 200 mm diameter plus waste. Most steel suppliers custom cut steel plate to any common shape. If you intend to cut 200 mm bar you need a pretty large bandsaw that can handle a blade over one inch wide and very course pitch to clear the chips. The chips binding in the middle of your 200 mm cut is likely what is shortening the life of your blades. Even if you used carbide the chips would still hang up and damage the blade. Randy
Thanks Robert.
For anyone else that might have some information to offer here, I'll clarify a few things...
The material was described as carbon steel by the supplier. Not sure of the exact composition. I'm actually trying to slice 20mm wide sections from a 200mm piece of stock. The sections are then faced and bored on a lathe.
I've previously done 20 tooth stock with no problems but this larger 28 tooth stock is wrecking the band saw blades after only cutting a part or two.
John

Wrecking the band saw blades how? If they are going dull on you, it may indeed be a higher carbon steel. Slow down the blade speed. Keep enough down pressure on it that it takes a chip. Use a quality cutting fluid of some sort.

Maybe I'm missing something here in my explanation. The stock I'm using is about 45mm in diameter and 200mm long. I'm cutting 20mm slices from the 200mm long stock. The timing pulley stock already has the 5mm-HTD teeth machined into it.
An example of the timing pulley stock...
An example of the smaller stock (about 30mm diameter) I've successfully made pulleys out of with no problems...
Sorry for any confusion.
I guess basically I'm asking is for best possible results using a band saw, what blade tpi and blade speed would be best? I had been using 10-14tpi variable tooth bi-metal blades but I think my blade speed was a little too high for the thicker stock material. The smaller diameter stuff (30mm) I previously used cut easy enough with at least 20 pieces cut on the same blade. The thicker stock (45mm) I'm now trying wrecked two new blades after a cut and a half each.
I greatly appreciate the effort of assistance.

Yup, best I can tell they're just dulling quickly.
My band saw doesn't have a built-in coolant/lub rig. Would a stick type blade lubricant be better?
I believe I might be surface hardening the stock then dulling the blade with too much speed thus excessive heat.

I'm not even going to spec a cutting fluid. I've used everything from Tap Magic to WD-40 to ATF, as well as wax lube, and it all works. If anybody has one that is better than the rest, I would like to know.
You could set up a coffee can/valve/tube drip lube system. A little awkward and messy, but it works.
Blades--I've tried a bunch of them over the years. Had my best luck with blades from Cut Technologies in Washington . 800-722-0305. Ask for Wayne.

Sorry John I am so used to larger sizes I misunderstood. I have used variable pitch blades and they help more than I would have thought when you have to change from thick to thin on a regular basis. I would be inclined to add a drip feed of coolant to wash the chips and cool or a small jet of compressed air to clear the saw kerf and cool. I have had a similar problem with a large saw cutting material over four inches thick. The blade teeth would be torn out by chips jamming in the kerf. The coolant could not flush them out of the long cut so we resorted to using a blow gun several times during the cut. Take a close look at a unserviceable blade. Are the teeth intact? Is the saw set being lost and is it on one side only? How sharp are the teeth when touched? This will give you a hint as to the problem. I have had no luck with saw wax other than with non-ferrous applications and very high speeds. Using too slow a speed is important when you are charging out your time, otherwise I would go for a slow speed as practical. 80 fpm is safe. Randy
Maybe I'm missing something here in my explanation. The stock I'm using is about 45mm in diameter and 200mm long. I'm cutting 20mm slices from the 200mm long stock. The timing pulley stock already has the 5mm-HTD teeth machined into it.
An example of the timing pulley stock...
An example of the smaller stock (about 30mm diameter) I've successfully made pulleys out of with no problems...
Sorry for any confusion.
I guess basically I'm asking is for best possible results using a band saw, what blade tpi and blade speed would be best? I had been using 10-14tpi variable tooth bi-metal blades but I think my blade speed was a little too high for the thicker stock material. The smaller diameter stuff
(30mm) I previously used cut easy enough with at least 20 pieces cut on the same blade. The thicker stock (45mm) I'm now trying wrecked two new blades after a cut and a half each.
I greatly appreciate the effort of assistance.

| Not a welding question but I figure there are lots of experienced folks | here that can give me some insight. | | I've got a project that requires me to section 2" carbon steel pulley | stock (timing pulley type for belts) with clean square cuts.
I keep thinking that an issue here is a tooth spacing that will cut the middle of the stock and at the same time be able to start a cut in the teeth of the pulley without breaking. I had this idea of starting a cut all the way around using a small tooth blade and then switching to a bigger one for the more tenuous cut, but that's a lot of work.

Have you tried using the lathe to part off the stock, or just the tooth area. Probably and hardness problem. Could be job for a cold saw?? Hope this helps..

Problem solved.
I appreciate everyone's input. It appears as though I was unintentionally setup for failure from the beginning by what seems to be defective blades. My dad brought over a used cheap blade he had in his garage so he could observe the saw in operation and perhaps give me some insight. Much to my dismay, the used inexpensive 14tpi blade sliced through the stock trouble-free several times with no signs of excessive wear.
Our conclusion now is that the original bi-metal 2 blades I began the project with must somehow be defective allowing them to wear prematurely. Go figure.
Though this has been a frustrating experience, I wont say its been wasted time. Because of some of the suggestions I've gotten, I set up a jet air cooling system that I'm sure will help me better utilize my inexpensive band saw.
Thanks again everyone.
John
My dad mentioned that he appeared the blade speed was much too fast

I have a hunch the pulley stock you are working on is just a bit harder than the last ones. That and you are getting into the hardness range similar to the blades you are using. Just a few Rockwell points difference is the difference between decent life and junk.
John wrote:

Something I had originally suspected as well and it makes sense. Today I did contact the vendor from where I ordered the 2 bi-metal blades that failed quickly and they acknowledged there are problems with a recent batch they received. It was described to me that the tool steel edge was never applied to the blade during manufacturing and the teeth were cut using only the backing material. I'm not real familiar with band saw blade manufacturing so I'm not sure what he meant exactly. I assume the blades being 'bi-metal' he meant the harder component was never added to the blade?
John

The intent is to have a set of hard teeth attached to a softer and tougher backing. Sounds like your baldes were junk before you got them.
I've had a process that worked for months, one morning the teeth got ripped out of 4 blades in an hour. Much investigation later found that one piece of flat stock had a much higher carbon content than usual. Welding on it hardened it to the point where the blades were no match.
John wrote:

I agree with using the parting tool in the lathe. I assume you have power feed on it. What the heck it don't get no easier than that. The stock is only 45mm in dia. Should be a piece of cake. If you insist on using the bandsaw with the bimetal blade remember that you have to break them in when new. Use very light feed and run your saw as slow as possible. After a few cuts you can increase the down pressure some. A good bi-metal blade should last a long long time. Remember, if you buy cheap stuff you get cheap stuff so get a good quality blade. It will make your life a lot simpler.

They were Starrett bi-metal blades. At least that is what they were supposed to be and were indicated the labels of each. I've ordered the same in the past from the same vendor as was completely satisfied previously.
I did indeed part a few pieces off on the lathe when I originally ran into trouble with the band saw. I don't have a power feed on my lathe in my home garage shop and I figured the band saw was faster with less steps on the lathe. Fortunately since I changed from the 2 newer blades that failed quickly, the band saw has worked as expected with 16 pieces easily cut today using the cheap used carbon steal blade my dad brought over. I'll be going by the local welding supply tomorrow to purchase 2 new bi-metal blades since they will cut a little more efficiently and are my preference.
John

"John" wrote in message news:xxwHf.24868$ snipped-for-privacy@tornado.tampab ay.rr.com... : Not a welding question but I figure there are lots of experienced folks : here that can give me some insight. : : I've got a project that requires me to section 2" carbon steel pulley : stock (timing pulley type for belts) with clean square cuts. The sections : will then be worked on a lathe. Anyway, I'm not experienced in cutting such : thick stock other than much softer aluminum and brass. I've got an : inexpensive Chinese made metal band saw such as what can purchased at : Northern Tool and Harbor Freight and it uses 64.5" blades. Whet is the best : blade type, tpi, and blade speed for successful cuts while keeping the blade : around a while. So far I've been able to locate bi-metal blades with a 10 : tooth count locally that has a variable tooth layout. I've been told that : perhaps even less of a tooth per inch would be better such as 6 or 8 and I : can special order them. I've also located rather expensive carbide tipped : blades with 3 tpi but at around $70 each. : : I'm not sure what speed I should run the blade. I assume the slowest : possible which I think is around 80 fpm. : : Several years ago I tried using a home wood working band saw with bi-metal : blades with some metal bar and I didn't have much luck getting the $20 : blades to last long at all. I assume because of the fast blade speed. : : I'm not opposed to purchasing the expensive carbide blade if it would be : best. Durability is my goal here. I don't want to have to change the blade : after every cut or two. : : I appreciate any input. : : : John :
I wouldn't use a bandsaw, try to use a power hacksaw with adjustable blade loading, 14tpi high speed steel blade and 10" stroke.
Smolley