Wondering what TPI (teeth per inch) should we get for our bandsaw blade. It is mostly used to cut aluminum tubes and some steel hexshafts. And if anyone had any recommendations on brands too?
Generally, you want a relatively high TPI, somewhere between 14 and 24, for cutting most metals. Check the blade you intend to buy to be sure it is intended for metal cutting. It will usually be wider (1/2" is common) and made of tool steel. This is especially important for cutting things like steel hex shaft, which is thicker than most other low carbon steels you’ll cut (like mild steel bar stock.)
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thank you, good to know
At least on the old Brodhead J-Line vertical bandsaw, we use a 14/18 tooth variable tpi blade (approx 16 tpi) but we also strictly say no steel cutting with it so that it lasts longer. 144 in (12 ft 0 in) x 0.50 (1/2 in.) x 0.025 x 14/18v Diemaster 2
We have a HF horizontal bandsaw with a 14 tpi blade we do cut steel with. https://www.harborfreight.com/horizontal-vertical-metal-cutting-bandsaw-93762.html
Starret and Lennox blades are worth the money.
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Bimetal blades last a lot longer than single metal blades.
If your kiddos cut thin metal on the bandsaw (especially steel or stainless) then you are likely going to be stuck with really fine toothed carbon steel blades as the only way to get enough teeth in contact.
Coil stock is far cheaper, but the welder is $$. I usually make a run of 4-5 blades at a time for the FRC bandsaw.
Although its a little pricey I was looking at this one in the hopes that it may last close to the whole season without having to replace it. Any thoughts or insights?
Bimetal blades intended for metal are very good recommendations. TPI should be based on how many teeth will be in the material at any given time. The shop instructors back in engineering school said 3 teeth is a good aim, for 1/8" plate that would be 24TPI, and I find that too be too many. In FRC you’ll probably be cutting stuff with wall thickness as thin is .040" and bars 1/2" or larger so there is no perfect tooth count unless you change blades all the time. I like 18TPI and when we need to cut something really thick I either accept that I’ll be leaving the bandsaw on it for 20 min or just go to the miter saw.
You want a minimum of 3 teeth engaged with the cut at any given time and a maximum of ~18 (some people say 24). This means you “need” potentially different tooth counts for different thickness ranges.
McMaster used to have a really good guide to choosing bandsaw blades that showed up at the top of the bandsaw blade overview page, but I can’t find it anymore.
You ideally want variable pitch/variable set blades. These help lower vibration and cut more smoothly. You can see below how the teeth are at different pitch between teeth as well as the root of the teeth are at different heights.
a 10-14 variable pitch/set blade is going to be good from ~0.25" to 1.25" but its sweet spot is going to be closer to the middle of that range. For a vertical bandsaw and FRC materials that is probably actually a little too coarse and 14-18 would be better.
Keep in mind that thin wall tubing is only momentarily going to have full engagement and then drop to a fraction of tooth-material engagement.
Number of teeth has no bearing on material being cut - the same rule of 3-18 teeth applies whether steel or aluminum. You would want a bi-metal blade as mentioned above, for steels. Your biggest problem is that unless you have a variable speed bandsaw you just should not use it for cutting steel.
There’s pretty much two styles of bandsaws folks are using in FRC - wood bandsaws with metal cutting blades, which have a very high surface feet per minute of blade travel (like 1,000 to 5,000 SFM) and portable metal cutting bandsaws which could be appropriate for cutting steel (Something like 100-300 SFM). You should be very sure of what you have before attempting to cut steel, otherwise you’re just going to destroy blades.
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with 10-14 TPI the teeth will be .10"- .07" apart so if you’re using stock with .063" or thinner walls or plate the stock can actually fit into the gullet instead of scrape along the surface of the cut. When your stock falls into the gullet of the teeth you will get very high chip load resulting in reduced the life of the blade and quality of the cut, and increased vibration and noise.
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That same blade is $10 cheaper on McMaster. It’s a good blade (we use the same series on both our vertical and horizontal bandsaws in different lengths/widths), but the fact you’re looking at a 92.5" long blade makes me highly suspect you have a wood cutting bandsaw, which would destroy this (or any) blade in steel in quick order - what model is your saw?
I believe it is something similar to this. That being said, with our extremely low budget, this is one of the only options we have for cutting our tube stock. We have been using it to cut our aluminum and the occasional steel hex for many years now. We were just trying to find a blade that would last close to the whole season or so, instead of having to replace blades all the time. I am a new mentor after a long break after graduating, so I am new to this a little, but from what it seems you were saying, we would have better luck going with a 14-18 tpi blade for our application?
A 10-18 tooth is probably going to be happier for you, for most things.
I personally would never cut steel on that saw. 1630 FPM is WAY too fast. Get a good hacksaw blade - it will take a minute or two to cut, but you’re not going to trash a $50 blade every time you cut steel. If that were my saw and someone cut steel on it, the blade would go straight in the trash. You just can’t get around the fact that the max speed you want to cut steel at is 1/5 the slowest speed that saw offers.
If people cut only aluminum and used reasonable feeds, that blade could probably last you a whole season. Even in aluminum you’ll want to run at the slower of those two speeds. I’d also recommend periodically hitting it with some cutting wax to lubricate the blade. You just push the stick of wax into the blade and hold it there for a couple seconds every so often.
PS I edited your post to add the missing “l” to the Lowes link - “owes. com” is some kind of malware domain
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Thank you for all your help and insight! I greatly appreciate all of your knowledge on the subject. And thanks for fixing the link must have missed the L when I copied it.
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It may be possible also be possible to change out some of the pulleys on your bandsaw to reduce the speed for better metal cutting. You’re unlikely to get the speed down to the ideal but you may be able to make an improvement for not too much money.
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If you really want to get into the weeds on it, Starrett has a 72 page band saw blade catalog
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A sheave swap will usually get you from wood → aluminum, but not wood → steel. Most steel-cutting bandsaws have two stages of reduction, whereas most wood-cutting saws have one.
If the bandsaw happens to have a 3-phase motor, a sheave change plus a variable-frequency drive can work. The saw will be limited to a much lower power while cutting steel, though.
There are also some hacky possibilities if you have an extra motor lying around.
That said, these methods are expensive and/or effortful compared to using a portaband in a stand or a Harbor Freight horizontal saw upright with a table attachment.
Hmm, now here’s an interesting idea: put a ClearPath motor in a bandsaw. Easy variable speed.
“”“easy”“”
Can confirm: re-powering a bandsaw to be variable speed is a pain. Sometimes worth it, though.
The pain isn’t in the motor swap (if using the same NEMA frame size), and even using a separate VFD isn’t too bad; it’s the overcurrent protection and control/safety stuff.
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