Controlling Bandsaw Speed

[brianhabby]

Does anyone on here know anything about controlling electric motors?

My Axminster SBW3501B Bandsaw has a 1HP (0.75kW) single phase induction motor. There are four wires going to the motor from the switch plus earth so a total of five wires; they are numbered 1 to 4.

Is it possible to control the speed of this motor? The reason is that I would like to slow it down so I can install a metal cutting blade.

regards

Brian

 

[Inspector]

Not with a single phase motor. You have 2 choices.

Put a smaller pulley on the motor and larger on the drive wheel or put in an intermediate shaft and pulleys. A jackshaft over here.

Replace the motor with a 3 phase delta wound motor and run it with a Variable Frequency Drive (VFD). Then you can slow the motor to whatever speed you like for the situation you find yourself in.

If you only want to cut aluminium a wood blade works without slowing the saw down.
Pete

 

[brianhabby]

Thanks Pete,

I was hoping I could cut steel on it but it sounds like that is not going to be an option.

Cheers,

Brian

 

[Myfordman]

You need to get the blade speed down by possibly a factor of 30 to cut steel - think 100feet per minute-
This is too much for a single belt drive so you need two in cascade eg a 5:1 followed by 6:1
I've done it using an inverter& 3 phase motor as well as a pulley system.
The write up is on here under my 9fingers user name.

Here it is modifications-to-a-startrite-bandsaw-t38613.html

 

[brianhabby]

Thanks,

I think if I go for a 3 phase motor and VFD by the time I've done that I may as well buy a small metal cutting bandsaw that would do the job out of the box. I've got my eye on the Makita 2107FK which I have found on eBay for £348.

There's no way I could fit extra pulleys on there as space is really tight.

Regards

Brian

 

[AES]

The other thing about cutting metals like steel on a wood band saw (apart from the massive speed reduction needed as quite correctly identified above) is the fact that unless you're just cutting tiny bits, invariably some sort of lubrication is called for - doesn't matter so much what the liquid is as the fact that A) you've got to get the liquid on to the cut, (a brush sounds a bit dodgy) and B) when you go back to cutting wood, you've got to get all the mess out of the machine again (i.e. "oily" residue plus the metal swarf), otherwise you'll ruin the wood.

I'm not saying it's impossible but if you look at the sticky on hack sawing in the General Metalworking section here you'll see there that I did discuss this in a bit more detail with the conclusion that using one machine for both jobs is not really feasible unless it's the odd bit of ali - not "impossible" note, but certainly not something to do on an "off hand" basis. I backed that up with a couple of pix showing the obvious differences between wood and metal band saws (their layout & construction).

Personally I'd say that if you've only got a bit of steel to cut "now and then" it's better to get your (hand) hack saw out. used properly with the right blade and correct technique it doesn't take all that long and isn't too hard (even in this weather)!

If you've got a lot to cut on a pretty regular basis (like some sort of fabrication shop for example) then it's much better to buy the proper saw, or a powered hack saw. If funds don't permit either then perhaps you can find a local jobbing shop who can cut stuff up for you, or a model engineering mate or club locally who may well be prepared to cut sets of stuff up for you (they often have a powered hack saw or metal band saw) in return for a contribution to their club funds.

Sorry, don't want to rain on your parade but HTH anyway.

Edit for P.S. I don't know the machine you've referred, to but as above, if you can run to it, getting the right machine for the job is the way to go (even if it's only a little relatively low-powered machine which may take a long time to cut big sections).

 

[Rorschach]

How much steel cutting do you need to do?

I have a Porta-band style metal cutting bandsaw, it can be used hand held and has variable speed. It's noisy but works great. I made a modification to allow me to put it upright in a vice and added a small table so I can move the work rather than the saw. Works a treat and covers all my (non-hardened) metal cutting needs.

 

[AES]

That sounds interesting Rorschach. Don't think I know that machine. Would you mind posting a pic of it, or a link to it please?

TIA

 

[Rorschach]

I have a woodstar PB06, which is a budget version, though mine works superbly, if maybe a little noisy from the generic universal motor.

I am not sure if that model is still available, they were very cheap, I only paid £40 about 5 years ago. I am sure similar type saws are out there though.

 

[AES]

Thanks for the piccie Rorschach. I've never ever seen a machine like that (or not that I've noticed seeing before anyway). It looks like a pretty useful machine. Must take a lot of sweat out of repetitive cutting compared to a hand hack saw (even with the correct blade & technique).

You learn something new every day.

Cheers

 

[brianhabby]

It appears the only one available in the UK at 240v is the Makita one referred to above. There are numerous models available at very good prices in America but very limited choice in the UK.

Thanks everyone for all your input.

regards

Brian

 

[Bodgers]

Just a bit of extra info if anyone sees this later and is thinking about a bandsaw primarily for cutting wood that can also double up to do some light metal cutting - the Scheppach Basa 3 is a good choice as it has a sort of variable gear adjuster where you can slow it down for putting a metal cutting blade. I have occasionaly cut aluminium on mine like this, and it works well.

Sent from my Redmi Note 5 using Tapatalk

 

[Sideways]

Portable bandsaws are 18v cordless tools. There are loads of them out there. Milwaukee, bosch, hitachi, starrett, dewalt, etc. One of the quieter ways to cut steel sections around 2-3 inches thick.

 

[John15]

Brian,
Axminster do a Trade bandsaw https://www.axminster.co.uk/axminster-t ... saw-508476. It has variable speed control suitable for cutting metal. I have the model BS11 which doesn't have the variable speed control - only suitable for wood. So far I'm finding it an excellent compact machine, if a little expensive.

John

 

[brianhabby]

Thanks for the useful replies guys. I have now ordered the Makita and it should be here tomorrow.

regards

Brian

 

[Rorschach]

FWIW you can cut aluminium on an ordinary wood cutting bandsaw with no adjustment to blade or speed. It's only really steel that needs a suitable blade and reduced speed.