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CB350Cafe first build
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Discussion Starter · #1 ·
I have an old 1939 craftsman bandsaw and I want to use it for cutting steel. I know the speed should be much slower than for say...wood.

Any rules of thumb for setting the speeds? I have a constant speed motor, and will have to modify the input v-belt pulley size, as well as the secondary pulley size.

Any thoughts would help. right now I have what I would guess to be an 1000 rpm motor, 4" driving pulley spinning a 6" pulley.

I haven't really done much reading yet on the matter, but thought I'd pick your collective brains!

Thanks!
 

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lɐʇuǝɯᴉɹǝdx&#4
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Typical wood cutting blade speeds are about 3000fps. For cutting steel, you want a blade speed of 100-200 fpm. So chances are you need to step it down to 1/20 or so of the current speed.

Here's a video showing a guy did it on an old saw with pulleys, chances are your machine is similar, so something like this could work. https://www.youtube.com/watch?v=6mavM220SV0
 

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Is my bike ok?
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I saw where you were talking about this in your build thread.

Do you own a sawzall? Easier to get good cuts than you think,blades are durable as hell (good ones) and it's ever handy for other thing,too. You could probably get a decent sawzall for what you'd invest in converting your machine.

Just a thought. :)
 

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CB350Cafe first build
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Discussion Starter · #4 ·
I will post up some stuff I pulled from my machinist handbook. I will definitely be doing a double reduction on my saw. Need to determine the RPM output of my motor.

got to fighter my saw before I can work on my heap :thumbsup:

...of course I will have some pics.

The material I have I might even have to reduce the FPM to 140 or so...that's quite a reduction.

:doh:
 
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CB350Cafe first build
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Discussion Starter · #5 ·
So the bandsaw…

In order to achieve 150 FPM to cut metal…
Main wheels on the saw are 12.375 OD…

Drive motor is 1750 rpm…
I would need a double reduction,
2” to a 12”
2” to a 12”

Those pulleys aren’t cheep man!

Any other options?

Reducer gear boxes are like 250 to 300 bucks.

Feeling discouraged at this point...maybe I could rig up a bicycle and let my kids pedal while I cut...

well...for the humor of it all...
https://www.youtube.com/watch?v=onHkk7kyd6c
 

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Is my bike ok?
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CB350Cafe first build
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393 Posts
Discussion Starter · #7 ·
I have found the pulleys I need for about 29 bucks each. Not sure how long it will take for me to get them but certainly much better than the 89 I saw earlier.

A friend of mine has the smaller ones for me...a couple of 2.5" and one 2" OD--all I need to do is take a run on the bike to pick them up :)

She's comin together--always something. I don't think a portable would do what I need. I am looking to cut out some patterns for levers and my rear-sets from plate.

I could have work cut them but don't want to abuse that privilege. I don't know...I do get a certain satisfaction of doing things on my own--the learning is invaluable. Costs a bit at times.
 
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CB350Cafe first build
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Discussion Starter · #8 ·
Ordered me some 12's today, should be here Friday, and with any luck, I will have myself a fightered 1939 Craftsman bandsaw with a double reduction so I can cut out my rearsets!

 
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CB350Cafe first build
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Discussion Starter · #9 ·
cant wait for my pulleys to arrive. :(
 

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lb/hp is what it's about!
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I just kept searching craigslist and found one already converted to metal usage. I got it for $60 and just had to put a new power cord on it. I say unless you need to cut something asap just wait for craigslist or pawn shops like was already mentioned.
 

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CB350Cafe first build
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Discussion Starter · #11 ·
thanks for the nudge to hold out...the bandsaw I have has mondo sentimental value...I will be the third generation to use it, as it was owned by my great grandfather.

I never met him but heard he was quite the mechanical genius, a phenomenal woodworker, and finished his career as a tool & die maker for Union Carbide.

It means the world to me that it is in my possession. Can't wait to fighter it, restore it, give her some fresh paint and get her back to brand new with a twist.
 

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CB350Cafe first build
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Discussion Starter · #12 ·
well a banner day...so far! haha--came home to a box of pulleys on the front porch yesterday.

Stopped at a buddies house and bored and reamed out the hub for a 5/8 shaft...here is a pic...hope to come up with the rest of the set up in the next day or two.

 

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CB350Cafe first build
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Discussion Starter · #13 ·
Well I did a little work tonight...welded some overlays to build up a shaft that was worn out from set-screws, pulley wobble, etc which happened over time.

The plan is to face, chamfer and turn the OD of the end to .627 and then polish her to a precise .625".

 

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CB350Cafe first build
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Discussion Starter · #14 ·
My point & shoot is sick so it will be tough to take pics until I get that sorted out...but was able to turn down the weld and plug, drill, pin, and hone the bore on a 12" pulley :) I hope to get some pics soon, but am in a position to get the bandsaw done which will hopefully be the gate to working on my rear sets! 49 rpm...here i come.
 

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CB350Cafe first build
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Discussion Starter · #15 ·
Filed some flats onto the newly machined shaft for the set screws, figured out how I am going to mount the mid range reduction pulleys using an old bench grinder bearing block.

Next item of business will be figuring out how to mount the motor.

I will also have to remove the saw from its base in order to add a clearance slot for the second 12" diameter pulley.

My point and shoot is confirmed dead :( So I might be forced to snap 2.0 Megapixel pics from my first gen LG ENV 1.
 
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CB350Cafe first build
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Discussion Starter · #17 ·
Well long overdue as they are, here are some pics of the progress so far on the bandsaw...I came into some maple butcherblock, and thought it would make a great table top for the stand in which to mount the saw onto.

so some pics...I welded up some of the brackets to secure the table top to the table frame--did this to all four corners.

Did the hole layout, complete with counterbores for the washers & nuts on the bottom side of the table.

Included a pic of the turned & polished shaft, complete with hand-filed flat for the pulley setscrew.

She's moving. Tomorrow I will pick up some carriage bolts, washers and nylocs to secure the saw to the table top, as well as secure the table top to the frame.

 
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CB350Cafe first build
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Discussion Starter · #19 ·
That's a beautiful piece of wood. Almost too nice to get dirty. :D
Hey man, this saw deserves the best ;) The maple top is already urethaned, but I am thinking of stripping it and staining it a dark walnut/cherry mix...painting the stand with either black bedliner paint, or gloss black rustoleum.

Got myself a bunch of hardware for the saw. Hoping to get some time in the shop tonight. Been whooped lately...spent all of thursday morning in the ER with my dad--hes doin ok...working too hard in his retirement and pinched some nerves in his back...so time off for that guy. running on fumes!

Stay tuned :) on a mission to get that saw a goin.
 
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