Suggestions for slowing down machine

[dikman]

Most servos are made in China and it's highly likely that they will have metric shafts so you should check the diameter as tt said. Pulleys can be picked up on ebay pretty cheap, but most that I have seen use a keyway and a nut on the end of the shaft to retain them, just make sure that's what your shaft uses.

I still don't understand why you can't get it to go slower, as the model you quote should be adjustable down to 0rpm according to the specs I saw.

[rockthecasbah121]

7 minutes ago, dikman said:

Most servos are made in China and it's highly likely that they will have metric shafts so you should check the diameter as tt said. Pulleys can be picked up on ebay pretty cheap, but most that I have seen use a keyway and a nut on the end of the shaft to retain them, just make sure that's what your shaft uses.

I still don't understand why you can't get it to go slower, as the model you quote should be adjustable down to 0rpm according to the specs I saw.

The “0” setting does not spin the shaft at all- I’m assuming this is to facilitate hand cranking? The next slowest setting is 350 rpm, but when we do our thickest runs which are only 7-12 stitches long, it needs more torque to get started and then takes off on us. This is probably something that could be overcome by practice, but my wife would rather just get rid of the machine rather than mess up a bunch of collars. 

[bullmoosepaddles]

@rockthecasbah121My Consew did the same thing. When I turned the rpm up enough to punch through the leather I was sewing. On the first few stitches it gained momentum and then did a sprint more than I could control on short runs, 1 to 1.5 inches in length. I typically sew at 5 spi, that is not a lot of reaction time.

A speed reducer will make your wife a happy lady. It did for me and mine.  

If you don't have an inexpensive set of calipers, Harbor Freight is your friend. 

Edited July 6, 2018 by bullmoosepaddles
added content

[rockthecasbah121]

1 hour ago, bullmoosepaddles said:

@rockthecasbah121My Consew did the same thing. When I turned the rpm up enough to punch through the leather I was sewing. On the first few stitches it gained momentum and then did a sprint more than I could control on short runs, 1 to 1.5 inches in length. I typically sew at 5 spi, that is not a lot of reaction time.

A speed reducer will make your wife a happy lady. It did for me and mine.  

If you don't have an inexpensive set of calipers, Harbor Freight is your friend. 

I'm going to get a caliper tonight and confirm the size of my current pulley and then try and find a 1.5" or smaller one to attach to the motor. If that doesn't work, I'll move on to a pre-made speed reducer. No returns on this machine, so I've got to make it work for my wife. 

[bullmoosepaddles]

@rockthecasbah121Your shaft is .750 3/4, or .787 if 20 mm. You won't find a smaller pulley for that diameter shaft. There has to be enough material left to provide strength, place for the key way and home for the grub screw to lock it to the shaft. Happy hunting.  

[chrisash]

Very easy to get a friend with a lath to turn one up or local machine shop

[Constabulary]

16 hours ago, BDAZ said:

I found on my machine that by changing the resistors in the speed controller, I can dramatically lower the maximum speed and have no problem getting a stitch every couple of seconds. 

Bob

could you explain that please   What do wee need

[rockthecasbah121]

Any advice on taking this pulley off? I assumed all I had to do was loosen the set screw and slide it off, but it feels like I’m going to break my hex socket before it budges. Am I missing something else I need to do first?

[Scoutmom103]

I watched a you tube video, where someone changed the pully, and they used a specialty tool to remove the pully.  I think it was called a gear puller.  They are available at auto parts stores.  

[dikman]

Well, there's no keyway, but I'm not sure why it has what appears to be a sleeve between the shaft and the pulley, that's usually only done when the pulley is too big for the shaft. Have you tried removing the grub screw completely and twisting the pulley to see if it's screwed on? If you can't get the pulley off I wouldn't worry too much as from what you've said about using it if you buy one of the commercially available speed reducers (one with a BIG pulley and a small one) I'm sure that will solve your problem.