Thread: clever diy hacksaw idea - woodworkers might like this too

Yes, clever and cute, but hardly practical. I get impatient just by watching the video.

Originally Posted by Marc

Yes, clever and cute, but hardly practical. I get impatient just by watching the video.

Thanks for the reply

I am very keen to learn, what should I read or do to better understand why this idea is not practical

Can't it be "beefed up" to run off a more powerful motor ?

Is the neat looking hinge mechanism stupid ?

Couldn't the wooden gears be replaced by something else to drive the saw ?

I simply don't know enough about mechanics to make an informed judgement.

Would welcome a more detailed comment please ?

Bill

My main objection to it would be that it is very slow. A weight on the frame would force it into the work more but as the maker said, that makes the cut dive off to one side. The other issue that needs to be addressed is the blade is being dragged back on the return so it is being prematurely blunted. Normally power hacksaws have a lift mechanism so that the return stroke is lifted slightly from the work.
The plywood gears may not be as durable as plastic or metal but would probably last. No point in putting on a more powerful motor as it would not make it cut faster with that set up.

I did like the pivot mechanism - it did make things more interesting to watch. It's an interesting build exercise but I suspect it would be faster to cut things by hand. Full marks for trying something out though.

Michael

I'd like to see the motor running the other way, the blade turned around......or more likely(as a WAG) both.

Of course it may make no difference what so ever

Stuart

With no weight on the frame, it's not going to be cutting properly, it needs a better frame, and heavier blade... but then it starts to look like a normal power hacksaw..

Looked very slow in the video..

Ray

Not to mention four ball bearing races which would add considerable cost, when, for the speeds and loads involved, a simple sleeve bearing would be fine - even one made out of nylon.

Thanks for the comments thats a big help to understanding how these gadgets work.

I live in hope of stumbling over a hacksaw or a bandsaw at a garage sale or ebay for tuppence, but until then will collect ideas to see if I can build one in the future.


Bill

As an added warning - there was a Gingery book out some time back that gave instructions for making a power hacksaw. I started following the instructions but when things didn't quite line up I started drawing things out on CAD and my conclusion was that it had not been checked or one made from the instructions before publishing. Looking at the design it would be prone to wear anyway so the accuracy would be questionable.
If you add up what you would spend on making one of these from scratch, a basic 4x6 gets pretty attractive. It is also one of the few bits of kit out of China that I think most people would agree do the job and are very durable without needing to be reworked (although there are lots of mods out there that can be made to them to make them better - a few forum threads here too)

Michael

Originally Posted by steamingbill

Thanks for the reply

I am very keen to learn, what should I read or do to better understand why this idea is not practical

Can't it be "beefed up" to run off a more powerful motor ?

Is the neat looking hinge mechanism stupid ?

Couldn't the wooden gears be replaced by something else to drive the saw ?

I simply don't know enough about mechanics to make an informed judgement.

Would welcome a more detailed comment please ?

Bill

Yes, ok, sorry if I came across a bit negative. that prototype seems to be something that was built for the fun of it and as such it is a great effort, particularly the gears.
The main defect of it as a practical power saw to be used for the intended purpose is highlighted by the author. A bit of weight is needed but the blade can not take it. Power saw have wide thick blades that don't bend, and weights added to them to cut accordingly.

Building a machine of any description is a project that takes lots of time, lots of investigation, lots of tools and machines and lots of money. Generally speaking if you want to build a machine because you find a ready made is too dear, you will end up spending more money than buying one that is old and needs restoring or one that is new out of China or India and perhaps needs a bit of improving.

E-bay and Gumtree are your friends. Save your time for other projects and find a hacksaw ready made is my advice. Unless you really want to make the power hacksaw you project than it is back to the drawing board. Forget that toy and search for something that will work.

My opinion only.

I feel that set up would work OK , provided it was built to take a 12 or 14 inch power hack saw blade, as it looks on utube its not much more than a powered hand hacksaw.

I can really vouch for the benefit of lifting the blade off the work during the return stroke. A friend of mine had an old power hacksaw that had the "blade lift on return stroke" mechanism disconnected and it was going thru blades at a silly rate. Eventually he reconnected the mechanism and he got a significantly extended blade life.

Clearly this project was made for the sheer fun of it, not unlike a Stirling engined coffee mug fan or a domino demonstration. None serve any purpose, aside from the entertainment and learning value, they're made/done just for the fun of it. How anyone could confuse this with a serious attempt at a power hacksaw is beyond me. Presumably you would also consider the Stirling engined coffee mug fan to be a serious attempt at a cooling fan and a domino demonstration as a true feat of engineering excellence - extraordinary.

I have a HM power hacksaw that does not have a return lift and have not had a problem with excessive blade wear.

Originally Posted by sacc51

Clearly this project was made for the sheer fun of it, not unlike a Stirling engined coffee mug fan or a domino demonstration. None serve any purpose, aside from the entertainment and learning value, they're made/done just for the fun of it. How anyone could confuse this with a serious attempt at a power hacksaw is beyond me. Presumably you would also consider the Stirling engined coffee mug fan to be a serious attempt at a cooling fan and a domino demonstration as a true feat of engineering excellence - extraordinary.

I'm sure some of you are very talented in some way, shame you can't include common sense and humility among your talents.

Are your egos so fragile as to consider your critiques essential in everything set before you? A little humility and common sense never go astray.

how many grumpy pills did you take yesterday........