Hacksaw machine

[olderdan]

Yet another hacksaw machine, this one is built from mostly second hand parts about two years ago.
Capacity is 4 inch square, stroke is 3 inches and speed is 125 cutting strokes per min.
I prefer the linear motion type instead of the rocking frame variety as it gives a better motion to the blade, so this design is dictated by the materials I had available and the need to make it using only a lathe and pillar drill.
The traditional method is to use hexagon bar but I already had some ¾ square bar available some 4 X 2 inch box channel and some 10mm alloy plate so a way of using all this was devised.
The motor is from an old cement mixer as is the Poly V drive belt, there are 10 ball races in total (all pre used but serviceable for this).
As is oblivious from the pics the blade frame rides under the guide arms on 4 races which take all the weight and the blade frame is keyed, bolted and welded as there is a lot of tension on this part. As is also apparent the frame would drop out when lifted so this was solved by two bronze discs on the top face which do no work except to keep things in place, all assemblies are pinned after set up alignment.
I had just enough hex bar for the vice part which helped, the large pulley is multi ply, this was machined and coated with resin and re-machined and mounted on a hub as I had run out of material for this,(a temporary measure which is still in service). Extra weights can be added but in practice are rarely needed and I have found the best blades are Eclipse Plus 30 bi metal HSS used dry as any lubricant seems to slow the cut.
I have just sliced of a piece of 2 inch EN8 bar which took under three minutes and is pretty accurate for this type of machine as long as care is taken in manufacture to make all faces square, I added a top guard from a piece of plastic pipe and the only purchased item has been a NVR switch working through an end of cut micro switch. I really wish I had made this years ago.

[tonyfoale]

nice one Dan. There are many things that when we eventually make them we wonder why we didn't do it yonks ago. I have often though about one of these but most of my steel cutting is tube and I use an abrasive wheel chop saw for that, or Aluminium and I use a carbide tipped wood saw blade in a chop saw for that. So I tell myself that I don't need one, rightly or wrongly I don't know.

[olderdan]

Thanks Tony
It sounds as though you do all right without one, I tend to work with steels of dubious origin including stainless.
I have heard that Rage saw blades will cut just about any metals or wood but not tried them myself.
regards
Olderdan

[DIYer]

Thanks olderdan! We've added your Electric Hacksaw to our Hacksaws category,
as well as to your builder page: olderdan's Homemade Tools. Your receipt:

Electric Hacksaw by olderdan

tags: hacksaw, motor

[JohnMTO]

Nice work- the linear motion was a great choice plus building things from what you have "in house" is ace in my book.

Any chance of liberating your Sketchup file on this project?

JohnMTO

[olderdan]

Nice work- the linear motion was a great choice plus building things from what you have "in house" is ace in my book.

Any chance of liberating your Sketchup file on this project?

JohnMTO

Thanks John
I have tons of Sketchup files to scale but they are to large to upload on HMT, the hacksaw one is 13.2MB.
I do not want a Google account or Dropbox for privacy concerns but would otherwise be happy to share if there is another way.
Regards
Olderdad

[tonyfoale]

I do not want a Google account or Dropbox for privacy concerns but would otherwise be happy to share if there is another way.
Olderdad

Alan,

I don't think that there are privacy concerns with Dropbox and it is free up to quite a lot of storage.
Another option would be a free website.

[JohnMTO]

A zip file is pretty straight forward. I suggested this (by PM) to olderdan along with my email address.

JohnMTO

[olderdan]

A zip file is pretty straight forward. I suggested this (by PM) to olderdan along with my email address.

JohnMTO

File sent to you John, hope it it is of some use to you.

[penca]

hi od i`m in a bit of a confusion right now as you say capacity is 4 inch but stroke is just 3 seems to me some teeth can`t evacuate properly as they never see the light or is 4 inch tube? hope it`s just me and this is a non issue for solid material
asking bc this one is on my list for my home shop, have a couple bandsaws and cold saw in my "business" shop. but it`s a few km from home... this little one would fit the small room i have at home.
thanks for sharing man.
pete