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velocette
10-14-2015, 09:03 PM
Bandsaw Re Power

My vertical band saw Was a converted woodworking machine with an 18 to 1 worm drive for cutting metal driven by a 1/2 hp motor

Three speed poly vee belt drive with 39 52 66 Metres Per Minute

A 1 hp motor and 3 speed poly vee belt direct drive gave 650 900 1100 metres per minute.

Becoming fed up having to swap belts for speed changes so time for improvement.

Having bought a 180 volts 1.5 hp Baldor DC motor from a factory closure sale for peanuts it was a brand new spare.

It gathered dust in my workshop for a while until a project to use it came to being.

Edit! Controller is a Minarik MM23001c 230 volts AC to 180 volts DC Thanks spongrich

Unsure if it would be possible to use it on the bandsaw some research over a period of time found that it was a possible conversion with some sacrifice

of top end speed for better torque at low speed.

Being a DC addict for a number of years gained experience setting up drive controllers to match the motor so it was eventualy game on.

Removed the motors and the gearbox and create enough room for the rather larger Baldor motor.

After trying different size poly vee 6 rib motor pulleys settled on 50 mm for the motor and 162 for the band wheel shaft.

This gave me from 39 metres per minute to 620 metres per minute.

Using a bi-metal blade for cutting mild steel, cast iron, and aluminium it will cope with light woodworking at slower feed rate at full speed

With a 6 teeth per inch woodworking blade it copes with resawing planks 200 mm wide.

While on the bandsaw mods can I pass on some more tips.

Some years ago I built a bandsaw from scratch using "A" section pulleys for the band wheels and "B" section belts for the tyres.

Top pulley tyre was cut with a scarfed join and glued in place.

Bottom pulley is the drive for the band with the blade running on the back and the driver pulley on a counter shaft located inside the saw blade Photos explain better.

Stepped "A" section pulleys give three speeds 453 254 136 metres per minute cutting speed.

Kicking this drive setup around for a while my thoughts are that instead of a "B" section belt that a "Poly Vee Belt" could be used for the drive.

This then means that the band speed is calculated on the circumference of the small driver pulley.

Photos at http://s1028.photobucket.com/user/velocette/library/?sort=3&page=1

Eric

spongerich
10-14-2015, 09:24 PM
"Conventional Wisdom" is that DC motors are a poor choice for machine tools and that 3 Phase with a VFD is the only way to go.

I recently converted my Clausing milling machine to a similar Baldor 1-1/2 HP DC motor and I've been extremely pleased with the result.
Sounds like it's worked well for your application too. It can be tricky to find the right controller/motor combination if they're not matched and you're scrounging up spares from who knows where, but IMO it's a great option, particularly for those of us who don't have ready access to 240v power in the shop.

Mcgyver
10-14-2015, 09:52 PM
not sure what the OP wants.....some guys never buy a paragraph, others, all they have is paragraphs :)


"Conventional Wisdom" is that DC motors are a poor choice for machine tools and that 3 Phase with a VFD is the only way to go.

I don't agree with that. VFD is a convenience but you lose all your hp at low speeds, unless you substantially overpower it. Best is a mechanical transmission, belts, gears etc.