A Quick Question About Speed Reducer Pulley Sizes

[OLDNSLOW]

I searched and did not find the answer to my question, and I can figure that the answer will very depending on weather it is store bought or home made, but would like to know what the common sizes of the speed reducer sets run.

Thanks to all who answer.

O n S

Ron

[Wishful]

If you are asking about what size the pulleys are I would say 9" and 3". There are a lot of variations. I am building one that has a 10 pulley and a smaller one that is a triple pulley that is 1.5,2.5 & 3 I believe.

[OLDNSLOW]

where are you going to put the 10 inch pulley?

[Uwe]

It's less about actual size than ratios between pulleys. A 2"/4"inch speed reducer pulley combo will have the same 2:1 speed-reducing effect as a 3"/6" combo. One popular commercial version actually has a three-in-one pulley : 3"/6"/9":

So depending on which two pulleys you put your belts on, you get a 1.5:1 (9":6"), 2:1 (6":3"), or 3:1 (9":3") ratio of speed reduction and torque increase.

Unless you're really into into wandering the aisles of your local hardware store and hours of tinkering, I highly recommend a commercial version. They're much easier to install and not much more expensive than home-made versions in my experience.

$130-$150 seems like a lot for two pieces of painted cast iron and a bearing, but I've yet to find a considerably better or cheaper alternative.

The only really cheaper way to reduce speed and increase torque is to change just the pulley on your motor to a smaller one. My Enduro motors come with 5" pulleys. Installing a 2" pulley is only $5 or so, but provides a very cheap 2.5:1 ratio improvement for speed reduction and torque increase.

If you want to go REALLY slow and REALLY high-torque, you do both, swap the motor pulley out for a smaller one AND install a speed reducer pulley BETWEEN the motor and machine.

Changing out the hand wheel on the machine is usually not a practical option.

Edited January 3, 2016 by Uwe

[dikman]

Uwe is right, it's a lot of messing around building pulley reducers - pulleys, suitable shaft, bearings of some sort, mounting for the bearings, a method of making the support adjustable. Those commercial ones might seem a bit on the expensive side, but they're neat, compact and relatively simple to fit.

As to size, if it's home-built it could be anything, depending on a) what the builder has lying around or what he can buy that's suitable. One of mine uses the typical 4"/1 3/4" pulleys that are commonly available on ebay (3/4" shaft). Another uses an 8" that I had lying around coupled with another 1 3/4". As for changing the handwheel, it's not that difficult, although it will obviously depend on the machine - my Singer 211G166 is a problem (which I'm working on). I'm a great believer in the handwheel option, although it may mean widening the belt slot on the table.

[OLDNSLOW]

Thanks for all the info.

[dikman]

Sorry about the smiley in my post, it's not supposed to be there! Apparently if I use a bracket and lower case b it inserts the smiley instead.

[Wishful]

I am making a variation of this, they go for over 200 so I thought I would give it a go. The 10" was the smallest big pulley they had at the hardware store so I am going with it. I already have a few smaller Pullies. The advantage to this type is that the machine will still tilt back and it bolts into the existing holes. Hopefully it will work....

http://i.ebayimg.com/00/s/NDgwWDY0MA==/z/X6UAAOxy7RBRYjjI/$T2eC16h,!yEE9s5jHPtcBRYjjIFHr!~~60_35.JPG

Some tips found here: http://makezine.com/2014/01/30/bandsaw-speed-changer-reducer/

Edited January 4, 2016 by Wishful

[TinkerTailor]

I am making a variation of this, they go for over 200 so I thought I would give it a go. The 10" was the smallest big pulley they had at the hardware store so I am going with it. I already have a few smaller Pullies. The advantage to this type is that the machine will still tilt back and it bolts into the existing holes. Hopefully it will work....

http://i.ebayimg.com/00/s/NDgwWDY0MA==/z/X6UAAOxy7RBRYjjI/$T2eC16h,!yEE9s5jHPtcBRYjjIFHr!~~60_35.JPG

Some tips found here: http://makezine.com/2014/01/30/bandsaw-speed-changer-reducer/

That first one you linked is a Cowboy and should be available from cowboy dealers btw.

Also, try heater/ac supply places. Older style of ventilation fans have belt drive pulleys on them. I also know heater guys would change belts to adjust air speed Also try farm and implement supply places. Farm stuff has belts everywhere. So do lawn mowers. I personally would hit the hardware store as the last resort for this part.

[OLDNSLOW]

well as it turns out I found a guy over the weekend that had a whole stack of pulleys all brand new with the bearings and shafts for sale for 25.00 so now I just need to put it all together.

[dikman]

Sounds like you did well with finding that lot. Whilst I used metal to make my housings, there's no reason that you couldn't use wood to hold the bearings. Like I said, it's a lot of messing around, but I consider it a challenge.

[dikman]

OLDNSLOW, this is a photo of the latest one I built (just for ideas?). I used a piece of black pipe that was fractionally bigger than the bearings, cut a slot down it with an angle grinder and welded lugs to it so that it can be tightened up on to the bearings. The vertical pieces have slots cut to give some adjustment and one piece is welded to the pipe and the other to the bottom piece. The shaft was turned down in two steps, one for the bearings and the other for the 3/4" needed for the pulleys (the big pulley was too big so I had to turn a sleeve to fit the shaft).

This was a bit of messing around, but I was trying to use whatever I had lying around, so cost was $0. The large pulley, coupled with two small ones (one on the motor) had a dramatic effect on the speed!!!

Edited January 6, 2016 by dikman

[OLDNSLOW]

I like the way you did that, I have already begun to put everything together and in the event it doesn't work out like I hope it will I will need to use something like you have there, so I might borrow that idea if mine doesn't work out.

Thanks

[Uwe]

Wow, respect, Mr. dikman! You got mad maker skills and access to cool machinery.

There seems to be much emphasis in many designs (including mine so far) to make sure that the shaft holding the two pulleys does NOT move, ever (other than rotate around the shaft's axis). I'm contemplating a version where the shaft is not fixed at all but moving freely on a track or pivot arm. I think we only need the shaft holding the two pulleys to not twist/yaw. Two opposing belts should hold it in place just fine.

[dikman]

Thanks Uwe, but the final product is pretty rough when you get up close! I figured it doesn't need to be a work-of-art as long as it's functional.

I've noticed that you seem to have a knack for engineering some pretty nice things, so I'm interested in what you can come up with regarding pulley reducers. Mine is based on pretty standard procedures for making these things (fixed/clamped bearings, as you point out), but if you can come up with a "floating" type it may prove better, as there's less chance of clamping things out of alignment.

The interesting thing with this one is the speed. I'm using a "standard" Consew clutch motor, and the needle speed is now very slow and feathering the clutch makes very little difference. This is on my post-bed Singer, with wheel rather than feet, and I just managed to snap a needle most convincingly while trying it on 1/4" leather!!! This machine does not like thickish leather, I've found, the roller wheel seems prone to causing a slight needle deflection on anything but thin leather.

[OLDNSLOW]

mine is going to look totally Cracker jack box stuff in compared to this stuff, I may have to rethink what I am doing before doing it. SHESH.

[dikman]

Don't worry about it, mate. My first effort was an open steel frame, sandwiching the bearings between plates, and a wooden pulley I made myself. There's a photo somewhere on one of my threads about the Singer (51K59). Looked pretty crude, but it worked! We all have to start somewhere, and it's only by making things that we learn (and get more ideas!).

You've got one big advantage over me when I started - you've picked up pulleys, shafts and bearings so have lots of stuff to play with. And remember, as long as it works for you is all that matters.

[SARK9]

Here are some more reducer pictures of some I make for my own machines....mostly, the main thing I find convenient is to have that telescoping mount for aiding the belt tension issues you can have when matching 2 belt lengths. Also, as many have noticed, you need to have the reducer pulley axle's centerline a bit behind your machine's hinge pivot point.....otherwise you can't tilt the head back normally without loosening the belt. I use an adapter plate to move the motor's mount point back and slightly to the right of the original holes to offset for the extra thickness of the pulley. I attach the plate using the existing holes in the table. Works very well.

-DC

One of the other multipliers as mounted:

-DC

[dikman]

Now that is nice work! Yep, two of mine I can't tilt back. One I have to loosen the reducer to slacken the belt (no big deal) and the other (post-bed) machine doesn't have hinges and is too tall to tilt anyway, so I just lift it out bodily!.

[gt2ride]

sark9

I like your reducer. did you mill the big pulley from flat stock? If so what thickness did you use.

would love to see a measured drawing.

I have more lathes then I do sewing machines. I have seven sewing machines.

Love to hear from you

gt