Speed Reducer And Servo Motor?

[Northmount]

Here are a couple pictures.

The slot in the table had to be lengthened to use the same belt as had been used for the motor. The pillowblock bearings are for a furnace fan that typically runs 900 RPM so I'm not worried about them lasting. Had to shift the motor over a bit, and play with the tensioning adjustments, finally decided to keep it real simple and use a bungee cord for the motor belt tension. For the belt to the head, just slide the jackshaft bracket down to adjust, then tighten the clamp to the leg. Since the leg material is on the light side, there is a block inside to keep the leg from being squashed.

Tom

[billymac814]

Thanks, that looks like it works well, I love the bungee cord. If you just got a different sized belt you could just use the motor adjustment right?

Just out of curiosity how much money and time do you have in that? I can see it being worthwhile if you have some of the parts laying around or have the free time but for someone like me who has neither its probably more cost effective to spend the 85.00 for a speed reducer from Bob. Although your bearings would be far superior but that's probably not a huge concern for most.

(The 85.00 version doesn't have ball bearings, 125.00 one does). I'm not knocking DIY or anything just comparing cost effectiveness.

Here are a couple pictures.

The slot in the table had to be lengthened to use the same belt as had been used for the motor. The pillowblock bearings are for a furnace fan that typically runs 900 RPM so I'm not worried about them lasting. Had to shift the motor over a bit, and play with the tensioning adjustments, finally decided to keep it real simple and use a bungee cord for the motor belt tension. For the belt to the head, just slide the jackshaft bracket down to adjust, then tighten the clamp to the leg. Since the leg material is on the light side, there is a block inside to keep the leg from being squashed.

Tom

Edited January 23, 2013 by billymac814

[Northmount]

Thanks, that looks like it works well, I love the bungee cord. If you just got a different sized belt you could just use the motor adjustment right?

Just out of curiosity how much money and time do you have in that? I can see it being worthwhile if you have some of the parts laying around or have the free time but for someone like me who has neither its probably more cost effective to spend the 85.00 for a speed reducer from Bob. Although your bearings would be far superior but that's probably not a huge concern for most.

(The 85.00 version doesn't have ball bearings, 125.00 one does). I'm not knocking DIY or anything just comparing cost effectiveness.

The motor tension direction was straight down before, now it has to swing more to the rear so the motor and tension brackets really need to be modified a little.

I spent probably around $40. I bought the bearings, small pulley and a short belt. The rest of the stuff I have around here. Do my own welding, etc. Even have the reamer I needed to fit the bushings to the shaft. But I have the time, being semi retired. So I work when health allows and complain the rest of the time.

If I was really busy, I'd buy the complete assembly and just have the installation time to worry about. These pillow block bearings are actually bushings. But they last a long time. So I wouldn't be concerned about a reducer using bushings. A good part of your machine head uses bushings.

Some of the speed reducers have stepped pulleys, so give you a fairly quick speed change if you need it. With the pulley all machined as one piece, takes less width so makes mounting easier, usually with one bracket on one side. Just have to get 2 belts the right length to go with it.

Tom

[Dignitas1980]

I have to thank to the first guy who initiate the post then, all of you for replays. Very helpfull! Again, thank you! and keep up the good work!

[Dignitas1980]

I have to thank to the first guy who initiate the post then, all of you for replays. Very helpfull! Again, thank you! and keep up the good work!

And...one question. can i change the sewing machine head pulley with a bigger one not to buy this reducer pulley? It will do the same work without damaging the internals? I`m just asking..

[Constabulary]

sure, if you can find a bigger one for your machine. Advantage of a speed reducer it that you can always keep it when you buy a new or different machine. The shaft diameter of the machine may vary so the larger pulley may or may not fit for different machines. The speed reducer works for all machines.

[alexitbe]

Does anyone have any drawings? In particular how they mounted the pulley...

I have found some scrap metal. I can make two pulleys with a size of 12cm :4cm.

Is 4 cm (1,6 inches) too small a diameter for a v-belt? The belts seem quite thick and stiff. What is the minimum size you guys would suggest?

Cheers

Alex

Edited February 2, 2015 by alexitbe

[Constabulary]

I think 40mm is pretty much the limit since you also need a shaft the pulley goes on with a diameter of lets say 15mm. I use 8mm belts on my 111G156 since they are a bit more flexible than the 10mm ones as it seems. So they go around the smaller pulely a bit smoother.

Search for Speed Reducer in the forum and you will find a lot of posts with different mountings. There are some really nice ideas.

How is the Duerkopp working?

[alexitbe]

Thanks for the answer Constab. It looks like I should go to 50 mm to be sure. Which means, ideally I will have to use a 20 cm diameter large pulley.. Maybe I should change to 8mm belts too, but belts aren't cheap here in Germany, unlike the UK.

Cheers

ALex

[Constabulary]

It depends - I`m buying on ebay from this seller:

http://stores.ebay.de/ATG-Gommern/_i.html?_nkw=keilriemen&_dmd=1&_sop=2&rt=nc

They sell STRONGBELT brand and I never ahd issues. I think the prices are good.