Parvalux motor

[Mick HenshallParticipant @mickhenshall99321]

I have a motor with following specs

12 volt dc max amps 6 watts output 45 rpm 3000

Rating continuous gearbox spec NM5.3 RPM 50

I already use one of these to power a mechanical hacksaw which is slow but does the job, question is would this motor have enough torque to run a handheld portable bandsaw? I am trying to build one using a 45" length blade with 10/14 tpi mainly to cut ferrous and non ferrous metals, blade speed would be around 180 ftpm, the torque is my main concern, any advice would be appreciated

Thanks Mick 🇬🇧

[Mick HenshallParticipant @mickhenshall99321]

[Neil WyattModerator @neilwyatt]

Six watts is a bit puny, to say the least. An Aldi bandsaw is 350 watts.

To get the blade to move at 100 feet per minute (low end) you will need a pulley with circumference 100/45=2.2 feet, that's 0.35 feet radius, say 100mm.

5Nm on a 100mm radius pulley will give you 50 newtons force at the rim, that's 5kg of pull. I think you need much more than that.

Neil

[Mick HenshallParticipant @mickhenshall99321]

Thanks Neil doesn't sound too hopeful, I do have a 240 ac motor with 2800 rpm maybe I could take the gearbox from the Parvalux and adapt it to fit the ac motor

Mick 🇬🇧

[Frances IoMParticipant @francesiom58905]

the current 6A would indicate more than 6 watts possibly nearer 70W – however taking the gearbox apart might not be that easy as worm is pinned to the motor drive shaft very close to where the shaft emerges and I suspect you would need to reduce the motor shaft diameter or live with a long extension (its also very messy as packed with grease)

[Mick HenshallParticipant @mickhenshall99321]

I have just found an Armstong ac motor with 2800 rpm and is 0.7 hp, problem is reducing rpm adapting gearbox still an option Frances but I take your points, I have some 1425 rpm motors, gonna have to ponder this maybe make a gearbox or use pulleys, nothing is easy is it but nothing ventured

Thanks Mick 🇬🇧

[SillyOldDufferModerator @sillyoldduffer]

In line with Frances, I read it as:

• 12 volt dc
• max amps 6
• watts output 45
• rpm 3000

I guess 45W is continuous, with up to 72W input peak. Still weedy for a bandsaw, but you could drop the blade speed and let the motor take its time.

Dave

 

Edited By SillyOldDuffer on 03/06/2019 21:55:48

[Mick HenshallParticipant @mickhenshall99321]

Clutching at straws I have seen on YT a home made hand held bandsaw driven by a battery drill, seemed to cut through light section steel sections fine which is all I want to do, I don't want to part with £300-£400 for a commercial one and I like the challenge of making one if it works then great if it don't I'll stick a higher rpm motor on it and use it for woodwork

Thanks gents

Mick🇬🇧

[Neil WyattModerator @neilwyatt]

Posted by Frances IoM on 03/06/2019 21:33:43:
the current 6A would indicate more than 6 watts possibly nearer 70W – however taking the gearbox apart might not be that easy as worm is pinned to the motor drive shaft very close to where the shaft emerges and I suspect you would need to reduce the motor shaft diameter or live with a long extension (its also very messy as packed with grease)

Ah misread it as 6 Watts.

[Clive FosterParticipant @clivefoster55965]

Mick

If you do decide to use pulleys to reduce the speed 4 poly-Vee pulleys arranged in the same configuration as lathe back gear can give high reduction in compact space. Compared to ordinary V belt pulleys poly-Vee ones can be much smaller diameter. The drive one on my tumble drier is little more than an inch in diameter yet transmits considerable power!

You don't actually have to make the output shaft and motor shaft concentric. If the motor is of conventional construction with through studs extending the studs with suitable spacers and adding plates to carry the bearings makes for avery compact construction. I have done similar myself albeit with the output shaft offset.  Doesn't seem unreasonably difficult to use one of the carrier plates as part of the bandsaw bow.

Clive

Edited By Clive Foster on 04/06/2019 08:55:24

[duncan webster 1Participant @duncanwebster1]

There is some info relating metal removal rate to power at **LINK**

This is for turning, not sawing, but it's a start. Quick sum shows that even if all the power was available at the blade, it will be be terrible slow for cutting decent size bar

[Mick HenshallParticipant @mickhenshall99321]

Some interesting comments gents for which I thank you,having thought overnight (funny how things keep you awake)

I am thinking of using my Adcock & Shipley horizontal mill as the driving source,it has a 1Hp motor it has 15 speeds the lowest being 60 rpm, yet to decide to drive with a pulley on the arbor or from the spindle direct,there are also some work clearance issues to sort.Food food for thought.

Interesting comments Clive/Duncan

Mick🇬🇧

[Author]

Posts