Questions re: DIY box style speed reducer

[shelr1]

kgg,

1. it is a Pfaff 545, I recently purchased it. The clutch motor had a small pulley installed by the previous owner, so there was some speed reduction already.

2. Shaft dia. is 1/2", large pulley is 6" O.D. the small pulley is 1 3/4" O.D. These are rated for either 4l or 3l belts, I think I am close to a 4:1 reduction using a 3L belt.

[RockyAussie]

5 hours ago, shelr1 said:

I'm making progress. This is pretty close to kgg's design. 

It May be just the picture but it looks like the small pulley mounted where it is would not allow a belt to miss the motor above it on the way up to the machine head.

[dikman]

Very nice job, looks good. Now, if you coupled that to a servo you could make the machine crawl like a caterpillar! 

[shelr1]

RockyAussie, the belt will clear , it is a little hard to tell from that angle. Thanks for the input.

[Quade]

I can buy a 1 HP servo for under $200 US.  I'm wondering if the cost of parts for this reducer is approaching the cost of a servo?   I'd simply never use a clutch motor.  I took two to the dump the other day.  

[shelr1]

2 hours ago, Quade said:

I can buy a 1 HP servo for under $200 US.  I'm wondering if the cost of parts for this reducer is approaching the cost of a servo?   I'd simply never use a clutch motor.  I took two to the dump the other day.  

I have spent a little over $50.00 so far, add to that new belts about $9.00. I appreciate the servo motor option, I also really like the challenge of designing and implementing a mechanical reduction. 

[shelr1]

I got the belts installed, happy with the way it turned out.  

 

[fibersport]

Sheir1 - would you mind sharing some of the details on the pulleys and pillow block bearings such as vendor and specs?  Thanks 

[Constabulary]

Not sure what he used but cheap pillow blocks for 15mm shafts can be found on Ebay F.I.

Pillow Block Type KP002

https://www.ebay.com/itm/144782907792  

a 40mm and 120mm pulley (for 1:3 reduction) with 15mm bore can be found here:

https://www.ebay.com/itm/264553616997

15mm shaft:

https://www.ebay.com/itm/163869249505?var=463451784748

Just some suggestions

I have used these bits for some speed reducers and I´m running one with the above components on my Singer 51w post bed machine. I just have the reducer in a different position. Depends on your stand where you mount it. This is just how I did it.

 

EDIT:

You may find the bits cheaper if you dig deeper but smallest pulley here is 45mm

https://www.ebay.com/itm/272680918308

 

 

Edited July 15, 2023 by Constabulary

[Constabulary]

I forgot this picture: