Slicer Power Hacksaw in Projects in Metal

[velocette]

Looks good, but I think it could be improved if that motor drove everything in the other direction. That way on the back stroke, the arm/linkage would push up and minimize the drag on the blade. It appears it cuts on the pull stroke already.

The decision to cut on the "Pull Stroke" was that having used Japanese Woodworking Saw that cuts on the pull It makes sense that if you "Pull" to cut.

If you cut on the "Push" any flexibility in the frame or play in bearings would be magnified.

The frame plus The weights on top of the blade is up to 5 kilograms or 11 lbs no advantage in attempting to lift that weight.

The crank centre is lower than the wrist pin pulling down on the frame on the cutting stroke.

Eric

[mikem]

I found a piece of 3/8 by 1.5 in by 30 in. hot rolled bar for the guide bar but it is a little dog legged--over the 30 inches, about 1/4 inch bow. The bend is pretty much uniform, not bent in one place. What is the best way to straighten? One end in the vise and Crescent wrench on the other side?

[Chester]

We have discussed putting the back issues into digital format, but we still have a pretty large inventory to clear out. Plus, assembling and scanning all the issues is a task we havn't had the manpower for. One of these days...

Been thinking George.......many of us on here live in cold climates, have scanners, are retired and winter's coming too. How about us doing the scanning of the magazines in appreciation for what we have here and the magazines?? That way you could be ready to go once your inventory is down to a reasonable level.

If you think this could work, I'll commit to the first twelve issues of Projects in Metal. The details could be worked out later.

[Chester]

Hi
This Hacksaw is on "You Tube" a bit Heath Robinson but it uses hand hacksaw blades 18 TPI and cuts square and true

http://youtu.be/PkT5Gauwv9M

The problem with Chatter is that the blade pitch is not fine enough there should be at least 1 & 1/2 teeth per inch on the blade for the thickness of the material being cut

Eric

Looks good, but I think it could be improved if that motor drove everything in the other direction. That way on the back stroke, the arm/linkage would push up and minimize the drag on the blade. It appears it cuts on the pull stroke already.

[sasquatch]

Interesting concept and appears to be well built, that is interesting.

[velocette]

Hi
This Hacksaw is on "You Tube" a bit Heath Robinson but it uses hand hacksaw blades 18 TPI and cuts square and true

http://youtu.be/PkT5Gauwv9M

The problem with Chatter is that the blade pitch is not fine enough there should be at least 1 & 1/2 teeth per inch on the blade for the thickness of the material being cut

Eric

[Duffy]

Bearings both top and bottom and never mind the sides. Roller blade bearings are ideal-cheap and available. Total weight of the arm will be probably less than ten pounds.

[mikem]

Those Craftsman ones are cool looking too!

[flylo]

I picked up an old one & it's just fun to use! I also use the Surplus Center alot.

[mikem]

I was thinking about ball bearings in the bottom and ultra high weight plastic on the sides and top. Would regular ball bearings be OK or do I need roller bearings? Something better than the plastic for the slippery factor?

[Duffy]

MIKEM, I built one, more or less from a combination of the PM plans and Vince Gingery's plans. THEN I diverged a bit! I happened to have a boston gear 10:1 gear box c/w a 1/6 hp motor.
Two suggestions based on my own experience:- First make the guide bar from 1 1/2 x 3/8 stock, (hot rolled works fine.) Second, if you have them, mount 1/4" id ball bearings on the underside of your saw frame guides. Rolling friction eats a lot less power than sliding friction. also, the deeper guide bar gives a bit more lateral stability.
I found that most of my cutting was with 14 tpi blades. Starret Green Stripe worked just fine and cost about a buck each. I dont think that I ever used one till it was actually dull.
I also changed the base a bit and used a really cheap drill press vise with taller jaw plates.
I admit that my saw did not cut perfectly straight, perhaps a bit over 1/16" slope in 2.5," but I am easy to please!
For the investmet, and what I learned in the building, it turned out to be a pretty good saw. Then I bought a 4X6, mostly because the money was burning a hole in my pocket!

[George Bulliss]

We have discussed putting the back issues into digital format, but we still have a pretty large inventory to clear out. Plus, assembling and scanning all the issues is a task we havn't had the manpower for. One of these days...

[mikem]

Thanks for all the help!

George--maybe you can find a way to provide the reprints electronically and still protect your intellectual property. Possibly screen the purchaser's name across them so that if they reproduced them their name would be attached? That way it wouldn't take 5 days to get the info. We are so spoiled in this day of instant communication!

I am going to start getting my stuff together!

I have three bandsaws already--taiwanese, Wilton and a big Nebraska-made Olson. I had one of the Casting Specialties kits, built that and sold it, sorry to say. I just think that hacksaws are way cool!

I might combine the Slicer and the Casting Specialty designs to get the best of both in a compact design.

[browne92]

Not to hi-jack this thread, but I've bought from Surplus Center several times and have always been a satisfied customer.

Mikem, any reason you'd rather have the power hacksaw instead of the $150 HF bandsaw? Or is it just the fun of the build?

[George Bulliss]

I have the article in front of me right now and will see if I can’t get you some answers. It’s a little “sparse” in some areas…


>The questions are: What is the width of the gap between the angle irons on the bed?
The angle iron pieces clamp the 6” x 9” x 1/4" vertical piece and 1/4” spacers are used at the end and center. So, 1/4".

>What are the dimensions of the bar that the bow slides back and forth on?
The guide bar is listed as being 30” x 1-1/4” x 1/4".

>What are the sizes of the pulleys?
6” crank pulley, countershaft pulleys are 5-1/2” and 1-1/2”, didn’t see a mention of the motor pulley.

>How does the bow attach to the slide bar?
Spacers or “filler blocks” allow the vertical pieces of the frame to be clamped to the guide bar. The size of the filer blocks determines the clearance and can be adjusted to accommodate wear.

Hope this helps. Not all pieces are dimensioned in the article, but the photos are good and the design simple; you shouldn’t have any problems.