I am new to the forum and actually new to machine tools. Back in May, I acquired an RF 40 drill/mill and a full complement of tooling. I made a few warm up projects; a hole finder, a slot slot saw arbor and some home maintenance projects and adopted as my first real project, a power hacksaw.
They say necessity is the mother of invention but the internet is the mother of inspiration. Thanks to websites like The Hobby Machinist and Youtube inspiration is becomming more and more plentifull. There were a number of inspiring videos I found including many examples of homebrew power hacksaws from which I pulled together my version shown below.
I used Alibre to put my ideas together. The as-built shop drawings below will fill in some details. If anyone wishes to reproduce anything here you are welcome but make sure you do you own dimensional analysis and tolerancing.
Not included in the drawing: the rolling cart, geared motor, electrical and vice arrangement and commercial fasteners. The link pins are threaded 3/8 -18, 5/16 socket head cap screws secure the slide mounts and the brass crank is tapped 8-32 for finish head machine screws to mount the crank arm. The cart started life as a typewriter table but spent time as the base for my "Bicycle band saw" which utilized both full size bicycles wheels and 10 speed derailleur system. I made it during my 'wood phase' hence the red oak case with relief arc that allowed for bike wheel clearance. It served faithfully for many years but finally grew to be redundant although the 19" throat was nice.
There are things yet to do. I need to improve safety with a RUN relay which will be actuated with a start button and de-actuated by a blade shutoff switch. I will get rid of that motor hole which is due to get covered with an MDF top to hold two bench grinders. And, I am thinking of a ball bearing blade guide which would engage the blade and follow it down as the work is encountered.
The saw cuts very well as is but there is a slight tendency for the blade to swing left and right with the fore and aft stroke of the crank arm. This is not a big problem as a blade guide is required any way. For now the slotted fence serves as the blade guide. Motion is transferred to the brace through bronze bushings in the crank arm and brace handle and these two bearings, ideally, should both be in the same plane to eliminate the urge to wobble. This is the kind of thing that keeps me up at night but functionally, the saw will slice a nice .050" wafer off a 4" acetal rod.
They say necessity is the mother of invention but the internet is the mother of inspiration. Thanks to websites like The Hobby Machinist and Youtube inspiration is becomming more and more plentifull. There were a number of inspiring videos I found including many examples of homebrew power hacksaws from which I pulled together my version shown below.
I used Alibre to put my ideas together. The as-built shop drawings below will fill in some details. If anyone wishes to reproduce anything here you are welcome but make sure you do you own dimensional analysis and tolerancing.
Not included in the drawing: the rolling cart, geared motor, electrical and vice arrangement and commercial fasteners. The link pins are threaded 3/8 -18, 5/16 socket head cap screws secure the slide mounts and the brass crank is tapped 8-32 for finish head machine screws to mount the crank arm. The cart started life as a typewriter table but spent time as the base for my "Bicycle band saw" which utilized both full size bicycles wheels and 10 speed derailleur system. I made it during my 'wood phase' hence the red oak case with relief arc that allowed for bike wheel clearance. It served faithfully for many years but finally grew to be redundant although the 19" throat was nice.
There are things yet to do. I need to improve safety with a RUN relay which will be actuated with a start button and de-actuated by a blade shutoff switch. I will get rid of that motor hole which is due to get covered with an MDF top to hold two bench grinders. And, I am thinking of a ball bearing blade guide which would engage the blade and follow it down as the work is encountered.
The saw cuts very well as is but there is a slight tendency for the blade to swing left and right with the fore and aft stroke of the crank arm. This is not a big problem as a blade guide is required any way. For now the slotted fence serves as the blade guide. Motion is transferred to the brace through bronze bushings in the crank arm and brace handle and these two bearings, ideally, should both be in the same plane to eliminate the urge to wobble. This is the kind of thing that keeps me up at night but functionally, the saw will slice a nice .050" wafer off a 4" acetal rod.
Last edited by a moderator:
