variable speed

[donwatson]

I would like to fit a variable speed control to a NUTOOLS 22" scroll saw. Is this possible ?? and what should I be looking out for.
Don W

 

[novocaine]

A VFD thats worth about 3 times the price of the saw.
Yes its possivle. No its not worth it. Buy a machine with variable speed already.

 

[donwatson]

Thanks for that extremely quick reply.
I would like to use the 22" capability to make bigger pieces. Would it be ok to sacrifice the motor and speed control from a 16" machine ?? say an Aldi or Lidl machine ?
I just received the NUTOOL machine this afternoon and it is soaking in WD40, I should get a better look at it in the morning

 

[scrimper]

If the machine has an induction type motor (no carbon brushes) then it is not at all feasible, if it has a brush type or universal motor then it can be done cheaply. Most of these cheaper clone type machines usually do have an induction motor however.

 

[donwatson]

Thanks scrimper, if it has brushes then there is a possibilty to put something together ??

EDIT I had a look and there are no brush holders visible around the motor casing so it looks as if it is indeed an induction motor. I got some info. from the plate, Model No. MASS006BMA, Motor 1/8, 1 Ph, 240 V, 1720 RPM, 0.6 Amps. I found a manual for a 22" Grizzly that looks exactly the same machine.
At 1720 rpm it is pretty fast for cutting thin ply but I suppose I could stack cut if needed but it is a bit fast and only takes pinned blades I have a couple of Axminster blade holders that I can get to work but I really need variable speed for my work.
Would it be possible to swap out the motor and replace it with a motor and variable speed control from another machine ??. I have a spare 16" machine (Parkside) that could be used as a donor ??.
Thanks to everyone for your help I would just like to be able to use this 22" machine for larger projects.

 

[donwatson]

Back again with what I have found. Firstly there are no signs of brushes around the NUTOOLS machine so I suspect it must be an induction motor. The manual I found for the lookalike Grizzly machine shows brush holders at the end of the motor, so the two machines are NOT the same.
I would dearly love the 22" capabilities of this machine and am considering taking the motor and speed controller from a 16" Lidl machine and installing on this 22" machine. Would it be possible ?? Please.

 

[scrimper]

Well anything is possible but it's not a task I would like to carry out myself and I have over 45 years of repairing electrical items.
I don't want to offend you but the Nutool fretsaw is just one of many clones of a cheap far east made machine sold under a plethora of names, even some top brands such as Record Power sold them. If you watch any of my videos you will see that I have one of these under the Wickes brand. They are ok for general woodworking use but hard work for doing Fretwork/scrollsaw work, I rarely use mine preferring the Hegner.

In actual fact induction motors in fretsaws are far superior to brush type motors, they are very reliable often outlasting the life of a machine and of course they are smoother and cause less vibration. The downside is that they are more difficult to have variable speed fitted because generally the run at a fixed speed depending on the electrical supply.

My advice can only be keep the Nutool for general woodwork and look out for a good secondhand Hegner that is factory fitted with a variable speed induction motor. Hegner machines do hold their prices well but at least if you decide to sell one there is no shortage of people who will pay good money for it.

There are other makes with variable speed induction motors that are probably very good; but I have no experience of them.

Normally when I buy machines for my workshop I always try to buy those with induction motors, they are always more reliable and less harsh than brush type motors. the exception is things that need high speed such as drills and routers etc. (even some of these are now sold with brush-less motors but they are different to normal induction motors).

 

[Spectric]

I am not familiar with fret saws but gather having a variable speed is an advantage, I used to handle mainly three phase industrial and control, plus some Dc systems but do know you can run small single phase Ac motors from some VFD's, often restricted to certain types of motor like a PSC type motor where the capacitor is always connected or the type that uses a laminated frame with solid copper rings, as well as the winding and a cage type rotor the sort you would find in a record player . A Dc motor would be a good solution for your saw, easier and cheaper to provide control of the speed and maintain the torque.

 

[Fergie 307]

No reason theoretically why you couldn't fit the motor and speed controller from another machine. The issue will be how easy or difficult it would be to mount it, and link it up to the drive. You will only really find that out by looking at both and judging what needs doing. Could be fairly easy, or it could be a real pain. Also if you are intending to use a motor from a smaller machine, is it going to have sufficient power?

 

[donwatson]

Thanks for the well formed replies. I can see you have taken time to form an opinion and that is what I asked for.
@scrimper, the NUTOOL will do for some larger pieces in intarsia if needed but will be quite valuable for segmentation etc. on heavier pieces of wood. Thank you you for the Hegner suggestion that could well be viable. I want a machine that has a 22" or even 30" if I can afford it so I will wait and see what turns up.
@Spectric, Roy. I liked your answer but well above my pay grade. I was a Toolmaker for a long number of years and would have jumped at the chance to do these things with machinery but at 80 + years of age I will step back from to to learn too many new things.
@Fergie 307, you have put down what I was thinking. Should be doable but is it worth it ? Possibly better waiting for a Hegner as scrimper suggests. I really would like an Axminster 30" and if this lockdown continues I may be able to afford one when they become available.
Again thanks for the thoughts and the benefits of your experience
take care and stay safe
Don W

 

[novocaine]

hi Don.
having taken a quick look at the 22" nutool, I have the same machine although it's badged as a clarke.
I've never had an issue with it for cutting any thickness of stock and that includes metal work.
it's not as aggressive as the hegner style of machine which I think is down to the long arm sweep so I'd suggest you have a go with it and see how you do.

I did look at weather you could slow it down with a gearbox or even slide the motor back and fit a belt drive.
it didn't get much further than looking though.

 

[scrimper]

it's not as aggressive as the hegner style of machine which I think is down to the long arm sweep so I'd suggest you have a go with it and see how you do.

I have to say that I have never found my Hegner machine aggressive, in fact quite the opposite, in any case the normal long stroke style can easily be changed as provision has been made to alter the machine to short stroke by simply undoing a bolt and using the stroke arm in the shorter position. This is normally only needed for really thin or very delicate materials. I find that just adjusting the speed slower allows the cutting of thinner stuff without changing the stroke length.

 

[novocaine]

Hairy fluff. Just trying to be helpful.