Power hack saw

[pjf134]

I just picked up a stationary bike for the motor and I think I can make a power hack saw from it by using one of the pivots. It has a 2 speed motor 1/4-1/2 HP with a gear box to slow it down to a good speed for a saw. It has a high-low speed switch and a on-off switch for the pedals. I am looking for ideas to hook up a hack saw on it. I will get the seat and some other parts off to make it smaller, but would like to use the bottom frame since wires go thru it for the switches. The big spring in front is for adjusting person weight for the seat with the crank handle, so that can be removed. I do know I will have to make some sort of table w/vice somewhere on it and make a blade holder above it. The motor speed is 1140-1725 and the gear box slows it down to a speed similar to slow hand sawing speed which got me thinking about this in the first place. Any good ideas will be welcome. Thanks
Paul

 

[Hawkeye]

That sounds like a fun project, as long as it's just for the fun. I have a power hacksaw and it is faster than cutting by hand, but a lot slower than a portable or floor-model bandsaw.

Check out this thread: http://hobby-machinist.com/index.php?topic=2881.0

including the brief video attached to Reply #6.

If nothing else, you'll get some ideas on how to build yours.

Mike

 

[pjf134]

Hawkeye,
Thanks for the video it did give me some ideas like running it off the foot pedal shaft to get a long stroke for the saw. I guess I will have to put it on a stand to do this, but could just put it on my work bench too. I do have a air saw which is fast and noisy too, but works good for thicker stuff, also have a torch and welder too. I am retired and speed is not a big concern for me right now. I was also thinking about making it into a small shaper too, maybe both also, as I was needing a pulley or gear keyway slitter. I am thinking out load again. I used to design equipment for industrial shops and that is where my thinking comes from. More thinking is needed for this project before starting this.
Paul

 

[4GSR]

Just think, you could cut iron and exercise at the same time! ;0

 

[Hawkeye]

Paul,

Keep in mind that if you give it a long stroke, you will limit the width of stock you can cut, based on the length of your blade. Mine uses a 12" blade, has a 5" stroke and can cut a maximum 5 1/4" wide stock. If you're only going to cut 3" stock, max, you could go to a 7" stroke. Remember that you lose a bit of length for blade mounting.

 

[george wilson]

There have been power hacksaw attachments to mount on your lathe! I think I ran across one on Griffiths Engineering site. Look it up. A HUGE bunch of info on many,many different lathes and mills.

I took a LONG train ride up from London to go see Tony several years ago. He sells used Myford lathes and other things.

Your speed should not exceed 75 FPM if you plan to saw up tool steel stock(annealed,of course).

 

[JHWALKER18]

hi,

it would make a decent power hacksaw. I have a home-made one myself. I didn't build it though, it's maybe 30+ years old. It does use a 12" hss power hacksaw blade and has a 1/4hp motor. If you have the motor and gear reducer, you're 80% of the way there. With the frame 90%.

From what i've read, most saws run from about 60 to 100 strokes per minute, mine does about 90spm. Stroke length should be just a bit under half the stroke length.

I've read a few discussions about whether a saw needs to lift on the back-stroke or not to prevent excessive blade wear or breakage. My saw doesn't and from what i've seen, lifting or retarding the fall maybe isn't so important. My saw does unload the weight a bit on the backstroke though, simply by the cam coming around. The blade i'm using has been in the saw for at least 10 years. I should get a coarser pitch than the 14tpi in there now. It's a bit slow even for a hacksaw when sawing thick sections like 1"x3" bar. Perhaps a 8 or 10tpi might make me change my mind.

I'm not so sure about the shaper idea. The motor may be big enough for a bench sized shaper, but i wonder if the gear reducer angle drive is up to the power requirements that a shaper would place on it for use in steels. It might be ok for at least some aluminums, brass, or bronzes. It could have plastic or pot metals gears inside. Just a possible consideration.

Dalee

i also have a sawmaster power hack saw mfg in 30's or early 40's.
It requires a 12.5" long hack saw blade.
Does anyone out there know where i could buy a 12.5" long blade?

Please help

 

[chief]

if the motor goes out you can still use it LOL

 

[pjf134]

JHWALKER18.
If you have a adjustment screw and nut like a hand hacksaw you can use a 12" blade. You might have to make one or two for it if it does not. A 12" blade can be bought, but never heard of a 12 1/2". Stop off at a store that sells 12" blades and measure yours and theirs to make sure yours is a 12 1/2", just a thought.
Paul

 

[GK1918]

There somewhere was a quote, success comes from one who followed a dream. You already have a
start. I suggest to go with a 14" blade that you can get from any local hardware, mine just orders them
from their supplier. Trust me this is the most used machine I have. They are set and forget while you
answer the phone and shut themself off. Although mine built in 1914 way advanced not like new tin junk.
backstroke lift is hydraulic swivel vise auto oiler. This was 3phase its been running here for 30ys with
just a 110v washing mach. motor. flat belt of course. And yes its kind of shaper like gibs and all. samuel