Bandsaw Status (and more letters)

Machine Shop
#1

I pulled the blade off and tested the saw and the wheels were turning true. I replaced the (same) blade and adjusted the tension and pressure on the guide bearing and the weird movement cleared up There is still a weird vibration in low gear (enough for the machine to move) but that may be how it is currently positioned. We need a couple of people to help turn in back into position and to check that it is level. Someone other than me should look it over to make sure it can be put back into service.

We need to change the blade again. @Photomancer - did the blade I asked for on the MSC order make it onto the order? Nothing was received but that doesn’t mean they just weren’t out of them. We should get a couple of pre-welded blades as soon as possible.

Hopefully we can be back in service in a couple days. cheers!

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#2

I’m speculating (based upon a hunch and no solid data) that a key contributor to the bandsaw’s recurring dullness is people pushing stock through there too fast.

I asked David @Photomancer how fast he thought the feed rate should be and he suggested it should be comparable to the horizontal band saw. I was cutting 1" diameter alum rod on the horz band saw, and it took between 3 and 4 minutes per cut.

Now, it might just be me, but I was a little surprised that it should take 3-4 minutes to cut 1" of T6061 (and BTW, I’m not complaining about that time - it was just a learning experience). I’ll bet that the typical band saw user is pushing their stock through the Powermatic band saw much faster than that.

Next time I’m there, I think I will write on a long trip of blue tape, something to the effect of: Feed rate: 1 inch alum rod - 3 minutes per cut and then stick that on the bandsaw. Not saying everyone will read it, but some will and maybe that will clarify what a reasonable rate should be.

#3

Feed rates will depend upon the courseness of the teeth. The same tables in the machinery handbook we use for the mill and lathe also apply to the bandsaw.

The problem is pressure, which should be only light. Has anyone ever seen the equivalent of a torque wrench for feeding stock through the bandsaw?

#4

That is one of the reasons aluminum goes so slow, the TPI we have is designed to cut steel ! 12-14 TPI, Alumin can be 8-10. with deep gullets.

#5

the last blade was 1/2"- 10TPI.

#6

I believe there was a blade in the irder, it was $75 and with the discount something like $56. There are multiple shipments, three at leastm so it may not have come in. Do you want me to order another one or two so they are on handhand? Also another Cold Cut Blade and we can send the other out for sharpening. Blades are $160 or so, There is also Tungsten alloy M35 alloy avaible, not sure of cost, but supposed to last longer. If with $25 I suggest we try one and see.

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#7

I didn’t see any orders today. that is one blade which should hold us a while (week? :sob:)
It would be good to have a 2nd on hand, but we need to use these suckers until they are totally shot or broke. I don’t want to be changing them 10 times a month the way woodshop does. As for the coldsaw what info do you have on the ones that are in the cardboard box under the bench? If we have one there, let’s use it. Else, definately get a new one.

#8

The extra blades in the box have much large teeth and fewer teeth per inch. They would probably work okay on mild steel and brass as long as the wall .100" or maybe .125" even. No thin wall material, the teeth would grab and tear it out damaging the material as well as the blade.

I think when the new blade comes in, when we remove all the blade guards before putting in the new blade to be ordered, we could test cut some material with those other blades using different wall thicknesses and see what happens. We aren’t using them so may as well see what they do work on IMO.

#9

the new bandsaw blade is in and I will install it shortly. the 1/8" cutters are in and are in the appropriate slot. have at it.

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#10

Great, I will muscle some rebar through it at 4000 SFM tonight so that I normal the sharpness and it doesn’t surprise anyone… :slight_smile:

3 Likes
#11

The bandsaw is now back in service. Let’s hope it makes it thru the weekend at least.
Cheers!

4 Likes
#12

I want to just try cutting anything with a new blade to get a baseline :slight_smile:

#13

oh, it’s sweet as hell. better hurry. 2 people have already used it. it won’t last much longer! :grin:

#14

Thoughts on this chart which includes feed rate in square inches / minute ?

#15

I think we can cut that down to just the 3 big categories of brass, aluminum, and steel and just use the lowest common denominator for them.

#16

Mild Steel, 55< HRC.

#17

If you’re itchy to cut something, you can cut about a 3" hunk off a 1" diameter alum rod (inside the teaching cabinet). I cut the pieces for the students for Tuesday’s Sherline class, but I forgot that I need one piece for the students to practice on. :grin:

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#18

We got that cut for you and it is in the cabinet.

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#19

You are awesome!

I didn’t mean that someone needed to do my job for me. I just meant that if Jay was serious about trying out the new blade, I had something that actually needed doing.

Anyway, thanks mucho!

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#20

Supporting an Instructor is everybody’s job if they can help.

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