buffalobill plus Ed D Report post Posted January 21, 2013 just a quick question for you guys, whats the advantage of a speed reducer and servo motor on a flat bed machine?is it better than just a servo?more torque? just seen a couple on youtube and wondering why Quote Share this post Link to post Share on other sites
Ferg Report post Posted January 22, 2013 I have two sewing machines, flatbed and cylinder arm. Both have the same Servo Motor and speed reducer. The speed reducer enables the servo to maintain a more stable degree of power at whatever speed you desire to use. I love it. Have used mine enough that I increase the speed considerably on straight runs but I still like to sew fairly slow, makes it a lot easier for us old men to know where the needle is going. ferg Quote Share this post Link to post Share on other sites
Northmount Report post Posted January 22, 2013 Motors have reduced torque at low speeds. So when you are trying to go slow through a difficult part, there isn't enough torque to punch through thicker or harder leather. Then you either hand wheel it, so now have only one hand to guide the leather with, or you step on the pedal harder, and ... Whoops, went further and faster than you wanted too! So adding a speed reducer lets the motor run faster, so it has better torque output, plus the torque amplification due to the speed reducer, now you can run heavier leather at low speeds and keep both hands on the job. I have both a speed reducer and a servo with 3:1 gear reduction. Can go as slow as one stitch in three seconds, so can stop at any needle position, and make complicated turns, all without hand wheeling it. My top speed is a little on the slow side, but I'd sooner have it a little slow and have the torque I want at low speeds. Tom Quote Share this post Link to post Share on other sites
J Hayes Report post Posted January 22, 2013 Motors have reduced torque at low speeds. So when you are trying to go slow through a difficult part, there isn't enough torque to punch through thicker or harder leather. Then you either hand wheel it, so now have only one hand to guide the leather with, or you step on the pedal harder, and ... Whoops, went further and faster than you wanted too! So adding a speed reducer lets the motor run faster, so it has better torque output, plus the torque amplification due to the speed reducer, now you can run heavier leather at low speeds and keep both hands on the job. I have both a speed reducer and a servo with 3:1 gearing reduction. Can go as slow as one stitch in three seconds, so can stop at any needle position, and make complicated turns, all without hand wheeling it. My top speed is a little on the slow side, but I'd sooner have it a little slow and have the torque I want at low speeds. Tom You're running a reducer on a gear reduction servo motor? Was the servo with the gear reduction built in not doing it? I'm needing a new setup myself.,not trying to hijack. Jeremy Quote Share this post Link to post Share on other sites
Northmount Report post Posted January 22, 2013 You're running a reducer on a gear reduction servo motor? Was the servo with the gear reduction built in not doing it? I'm needing a new setup myself.,not trying to hijack. Jeremy Yup. I switched from a standard digital servo to the Sewslow pro, but still needed some help at low speed. So cobbled together a jack shaft with a 6" and a 3" pulley, added a short belt to the motor, and it does what I want now. Mine is a Techsew 2700, same as Cowboy 227, which has about a 4" pulley in the hand wheel. If you are getting a heavy stitcher with a large pulley on the head, you might not need to double up the reduction like I did. See if you can test out the machine first with the heaviest leather you will ever sew, and the lightest you expect to do on the same machine. Tom Quote Share this post Link to post Share on other sites
J Hayes Report post Posted January 22, 2013 Tom I've got a Singer 153w101, I believe yours is a clone of that, so its great to hear whats working for a similar machine. What do you mainly put through your machine? My clutch motor is s bit much even with a 1.75" motor pulley. Jeremy Quote Share this post Link to post Share on other sites
Northmount Report post Posted January 22, 2013 Tom I've got a Singer 153w101, I believe yours is a clone of that, so its great to hear whats working for a similar machine. What do you mainly put through your machine? My clutch motor is s bit much even with a 1.75" motor pulley. Jeremy Up to 2 each 8 to 10 oz veg tan. And as low as one 3-4 oz. 3-4 oz was obviously no problem. But 8 oz and up was a problem low speed wise. Tom Quote Share this post Link to post Share on other sites
buffalobill plus Ed D Report post Posted January 22, 2013 wow thanks for the great replies!!!!soooo much help here!!!! Quote Share this post Link to post Share on other sites
billymac814 Report post Posted January 22, 2013 Tom, I'd love to see pictures of your speed reducer set up. Yup. I switched from a standard digital servo to the Sewslow pro, but still needed some help at low speed. So cobbled together a jack shaft with a 6" and a 3" pulley, added a short belt to the motor, and it does what I want now. Mine is a Techsew 2700, same as Cowboy 227, which has about a 4" pulley in the hand wheel. If you are getting a heavy stitcher with a large pulley on the head, you might not need to double up the reduction like I did. See if you can test out the machine first with the heaviest leather you will ever sew, and the lightest you expect to do on the same machine. Tom Quote Share this post Link to post Share on other sites
J Hayes Report post Posted January 22, 2013 Tom, I'd love to see pictures of your speed reducer set up. +1 Jeremy Quote Share this post Link to post Share on other sites
Northmount Report post Posted January 23, 2013 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 Quote Share this post Link to post Share on other sites
billymac814 Report post Posted January 23, 2013 (edited) 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 Quote Share this post Link to post Share on other sites
Northmount Report post Posted January 23, 2013 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 Quote Share this post Link to post Share on other sites
Dignitas1980 Report post Posted February 2, 2015 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! Quote Share this post Link to post Share on other sites
Dignitas1980 Report post Posted February 2, 2015 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.. Quote Share this post Link to post Share on other sites
Constabulary Report post Posted February 2, 2015 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. Quote Share this post Link to post Share on other sites
alexitbe Report post Posted February 2, 2015 (edited) 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 Quote Share this post Link to post Share on other sites
Constabulary Report post Posted February 2, 2015 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? Quote Share this post Link to post Share on other sites
alexitbe Report post Posted February 3, 2015 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 Quote Share this post Link to post Share on other sites
Constabulary Report post Posted February 3, 2015 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. Quote Share this post Link to post Share on other sites
Dignitas1980 Report post Posted February 3, 2015 I have taking the idea of user northmound and i want to make myself a speed reducer. I found a pulley, it weight 675 grams, i will need a 13 mm belt, its an aluminium pulley and the owner has measured the outsite not the inside, but you`ll see what i`m talking about. I will need this one, a steel shaft and 2 ball bearings. I have skill so this will not be a problem. What do you think? Quote Share this post Link to post Share on other sites
Northmount Report post Posted February 3, 2015 Pulleys are typically measured at the outside diameter since the belt surface should ride even with the rim of the pulley, not on the bottom of the groove. You don't want a belt to ride on the bottom of the groove as you lose the surface area contact on the side of the belt and pulley. Then you have to tighten the belt too much to stop it from slipping. Overly tight belts may damage the supporting bearings. Pulleys and belts should be bought as matching widths. Tom Quote Share this post Link to post Share on other sites
Dignitas1980 Report post Posted February 4, 2015 Absolutely you are right! My "question" was about these 2 diameters.. It will make the machine more powerfull with a speed reducer 37mm - 120mm? Its enough this raport 37-120 mm or i need a bigger raport between diameters, something like 37-160 mm? Quote Share this post Link to post Share on other sites
Constabulary Report post Posted February 4, 2015 the smaller the small pulley and the bigger the large pulley the more reduction you have. You can run your servo at higher speed and you have more torque and lower sewing speed. 37mm -160 is about 1:3 reduction and 37mm to 160mm is about 1:4 reduction Quote Share this post Link to post Share on other sites
Dignitas1980 Report post Posted February 4, 2015 the smaller the small pulley and the bigger the large pulley the more reduction you have. You can run your servo at higher speed and you have more torque and lower sewing speed. 37mm -160 is about 1:3 reduction and 37mm to 160mm is about 1:4 reduction 37mm-160 is 1:3 reduction and 37mm-160mm is different, you mean 1:4? How come? The values are equals, no? Quote Share this post Link to post Share on other sites
