Ramblin' Dan's Workshop

The Sanctum of Fine Art and Invention

Notes on the Bandsaw

Sorry, not the musical type notes but bandsaws do make music if you love working with them.

I just broke a ¼ inch 6TPI carbon steel blade on my Delta 14 inch saw. It was over 20 years old so I think it was not too much of a shame. Far less than a dollar a year prorated cost. The teeth seemed to be still rather sharp as the blade only performed very intermittent home shop duty. I am not certain why it broke but it wasn’t at the weld. I was only cutting a 7/8” dowel so the load wasn’t great.

The blade did make a little nick in the table insert that surrounds the blade, but I don’t know if that caused the break or the nick was the result of the break. I put my ½” 6 TPI blade on the saw and all is working well. Almost all my cuts are straight and narrow blades are not good at straight cutting anyway. Narrow blades are for cutting curves and I just never put the wider blade back on.

What I did after the break was do some bandsaw blade research for a replacement blade. Wow! Talk about options. Here is a little bit of what I learned. A user can use a blade anyway they want but there are some guidelines. I suggest reading the websites on line yourself after Googling “bandsaw blades.” I am not going to get into a lot of detail here.

There is not a standard do-all blade, but I have tended to treat my saw that way. I have used my 14 inch bandsaw with a ¼ inch 6 TPI blade to cut up tree branches so I could set them out for the rubbish collector. If it cuts - do it, sort of thinking.

The most general blade option besides blade material and width of the blade is number of teeth. The rule is three teeth in the material at all times. So thin material needs more teeth per inch on the blade and thick material needs less. Blade width determines how straight of cut you get, the wider the straighter. Blade thickness is not discussed much.

These limits are not critical so a blade can be used well outside of it comfortable cutting zone. The results may not be pretty with a course blade and a fine tooth blade might plug up and burn in the cut, but now I know why.

My broken 6TPI blade would be best in ½ inch thick material. I can use it up to probably 1 inch material with little problem. It wouldn’t be the best choice for ¼ inch plywood. In that material a 12-14 TPI blade would be best.

For re-sawing boards there are blades with missing teeth (skip tooth) and/or larger gullets to allow for more sawdust removal in a thick cut. Like I said, blade choices are a complex science.

I started thinking about my Proxxon micro bandsaw (MBS). I have blades with up to 24 TPI. These are perfect for cutting thin sheet materials 0.125 inches thick. I usually keep the bimetal 10-14 TPI blade on the MBS for general purpose cutting (it has small sections of both TPI teeth.) I can see I should change to a finer, 24 TPI blade if I will be working on say 1/8 inch brass plate. I could use the bimetal blade but the cut will be much rougher. For a single cut I can live with imperfection rather than change the blade. The stock 14 TPI standard blade (also available in Swedish steel extra narrow width) is best in ¼ thick materials.

On the Proxxon MBS, ½ inch and thicker material can be cut with 14 TPI but only with reduced feed and careful monitoring of how the cut is progressing, letting the blade do the work. A 6 TPI blade would be nice for thicker wood sawing but not available from Proxxon. Someday I might get one made and see if the MBS can handle the load.

The most important point I want to remember on blade changes is the three tooth rule and install a proper blade. A fine tooth hack saw is lousy at cutting off a 2x4. I can do it but why use a hacksaw to build a house…

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