Ole South Report post Posted February 22, 2015 I just picked up a lightly used, early 70's Consew model 28 (Seiko Oem). Sews great. Seems to have the original Code 12 stand and all the paperwork. It's got a clutch with a 1/3 hp Westinghouse motor but no belt tension mechanism. Here is the problem... the belt. 5/16" (8mm) top, 1/4"(~6-7mm) thick 46" long for the stock pulleys. I've made a smaller pulley (1 3/4 OD,1/2" bore) to reduce top speed but can't find a drive belt long enough. The one that came with it is stapled like a treadle belt; I'm guessing for obvious reasons..., no other way to tension. I've fabricated a temporary belt from paracord and clear 5/16ths vinyl tubing to test. Probably don't really need the paracord core as the vinyl doesn't seem to stretch excessively but I'll need a more permanent solution. Any ideas where I can get a replacement belt? With the new pulley I'm looking at ~42" length. Does the Singer 78 use a similar belt? As an aside: this machine has been stored for at least 15-20 years. While sewing it's really hard to feather the clutch to maintain a steady 20spm without holding the hand wheel. Do I need to disassemble and clean the clutch plate or just practice more? If I install a servo motor then I'm still going to have a belt issue as a standard belt (M-4x) rides extremely high in the handwheel and I'm assuming most modern servo's are going to have 3/8" or 1/2" wide pulleys with a 3/4" bore. Thanks. Quote Share this post Link to post Share on other sites
Wizcrafts Report post Posted February 22, 2015 I don't know your setup, but the standard pulley and belt combination for industrial sewing machines and motors is 3/8 inch; Type 3L. 3L belts are available from every industrial sewing machine dealer in the World. In the USA they come marked in inch designations. In Canada and non-SAE countries, they are marked in metric notation. Type 3L v-belts can be purchased in one inch increments, from the low 30s through the high 60s and beyond. I have a peg full of them in my shop, ranging from 38" through 59". If your previous 46" belt was too long after installing a smaller motor pulley, order a 44" 3L v-belt. Or, remove the C-clip from one side of your existing round belt, cut off the necessary amount to get a tight fit, punch a 1/16" hole about 1/4" in from the new end, push the open end of the clip through the hole and use your pliers to squeeze it down. Quote Share this post Link to post Share on other sites
SARK9 Report post Posted February 22, 2015 When you look for v-belts on a website or catalog, you will see them listed as a "3L-390" or 3L-395". The -390 is a 39" belt, the -395 is a 39-1/2" belt. Be sure to get the best quality available for smooth, vibration free running. The guys on this site that have sewing supply shops probably have known good brands. -DC Quote Share this post Link to post Share on other sites
Ole South Report post Posted February 22, 2015 Thanks for the quick reply Wiz. I picked up spare 46" from a local shop (Marked China EW V-Belt M-46). It fits fine in the new clutch pulley I bought from them but that pulley is 3/4" bore. I was impatient so I turned a smaller clutch pulley out of Maple yesterday. I don't want to shorten the working belt (I already took ~1/2" out to take up stretch) in case I needed to go back to the 3 1/2 OD Consew pulley. 3L belts must be 30deg chamfer like the old belt? The M-46 is definately 40deg and rides halfway up out of the pulleys, it would probably work but... Do replacement servo-motors come fitted with a pulley? Quote Share this post Link to post Share on other sites
SARK9 Report post Posted February 22, 2015 Specs for the 3L pulley: Effective Outside Diameter in inches: Under 2.2-- 32deg. width at full dia .360 2.2-3.19-- 34 deg. """"""""""""""""" .364 3.2-4.2-- 36 deg. """"""""""""""""" .368 over 4.2--38 deg. """"""""""""""""" .372 Depth of groove .406 -DC Quote Share this post Link to post Share on other sites
Wizcrafts Report post Posted February 22, 2015 Replacement servo and clutch motors all normally ship with type 3L pulleys. The Family Sew motors I got from Toledo Industrial Sewing Machines were fitted with 50mm (2") 3L pulleys. The shaft ID is about 1/2 inch, I think. Clutch motors usually have 3/4" shafts. But the pulleys I have are all for 3L v-belts. Quote Share this post Link to post Share on other sites
Ole South Report post Posted February 22, 2015 Thanks Sark & Wiz, exactly the info I was lacking. I do short /intricate/stop-start runs (bags/purses etc...) do you think a servo will provide enough low end torque through 4-6oz leather? (chrome/veg). I've used sewing machines all my life but sewing leather brings a whole new dimension to the craft. Quote Share this post Link to post Share on other sites
Colt W Knight Report post Posted February 22, 2015 (edited) You can order just about any shape/size belt you want from McMaster-Carr http://www.mcmaster.com/#v-belts/=w0xi4i Input your dimensions on the screen to the left, and it will tell you what type of belts are available. If you are not sure which type to choose, you can read the descriptions to see which brand/type fit your needs. Looks about like an 8$ belt for your needs. Edited February 22, 2015 by Colt W Knight Quote Share this post Link to post Share on other sites
Ole South Report post Posted February 23, 2015 Yeah, McM was my first look; unfortunately I was looking for a 5/16 top x 1/4 thick. Those only come in max 20-22" lengths it seems. Quote Share this post Link to post Share on other sites
Wizcrafts Report post Posted February 23, 2015 Yeah, McM was my first look; unfortunately I was looking for a 5/16 top x 1/4 thick. Those only come in max 20-22" lengths it seems. Type 3L belts are 3/8 across the top, hence 3L designation. They are sold by industrial sewing machine dealers. You are unlikely to find them at auto parts stores that usually stock 4L (1/2 inch) belts for car pulleys. But, I just remembered that you made your own motor pulley. Measure the motor shaft and order a 2" replacement with the correct inside diameter from an industrial sewing machine dealer, along with the new, shorter (3L) belt. Quote Share this post Link to post Share on other sites
Wizcrafts Report post Posted February 23, 2015 Thanks Sark & Wiz, exactly the info I was lacking. I do short /intricate/stop-start runs (bags/purses etc...) do you think a servo will provide enough low end torque through 4-6oz leather? (chrome/veg). I've used sewing machines all my life but sewing leather brings a whole new dimension to the craft. The Family Sew FS-550, fitted with a 50mm (2") pulley will do that easily. You can get even more punching power by adding a speed reducer between the motor and machine. They are sold by industrial sewing machine dealers whose ad banners appear on top of the pages on LW.N. Quote Share this post Link to post Share on other sites
Darren Brosowski Report post Posted February 23, 2015 LOL Wiz, Australia is a "metric" country but belts are still sold in inch designations. The main difference seems to be that the standard sewing machine belt is an "M" classification which is what the Chinese also use Quote Share this post Link to post Share on other sites
Ole South Report post Posted March 1, 2015 Well.... the issue wasn't/isn't the pulley I made. It matches the hand-wheel and original Consew flange profile exactly. I think the problem is that since this machine is a clone of a 78-3 that it was probably designed for a round leather belt like the treadle machines (most likely a 5/16ths round belt). Remember the original clutch and motor has no tensioning mechanism on this unit either. A standard 3Lxxx belt rides almost halfway up out of the hand-wheel as well as the SR and/or clutch drive pulley. A segmented (cogged) belt rides slightly lower and handles the tight radii of small pulleys better. I've learned a lot about V-belts this past week. The biggest thing I learned is that we don't have the selection of belting we had 30 years ago! I don't know where the stapled belt stock came from that was fitted on the machine when I bought it from the original owner's grandson but it is definitely 5/16ths / 8mm top 1/4" thick with a 30deg angle(15deg chamfer each side).and fits perfectly (top of belt flush with pulley flanges, circa 1970 maybe??). Results: After installing a speed reducer I got a cogged 3L360 since it doesn't fatten as much going the pulleys as the solid v-belts and rides lower in the pulleys. I re-installed the original 3.5" clutch pulley, re-positioned the clutch and motor assembly and use a vinyl round belt for the bottom end (still not sure where the SR will end up if I get a servo motor) as I can make them up on the fly until everything settles out. I took a suggestion from a forum brother drilled a couple holes and moved the foot pedal linkage to the side of the treadle and I now have a decent top speed and hopefully acceptable low speed/torque punch power. Now if I can just find some presser feet for it. Quote Share this post Link to post Share on other sites
catskin Report post Posted March 1, 2015 Here is what I did to slow down my Singer 78-3 I had a fly wheel from a little old air compresser I lathed it out to fit on the hub of the original pulley while doing that trimmed the fins to fit on top of the hand wheel made it a gentle tap on fit put in the set screw and a longer belt and it runs just fine I didn't have to move the motor or enlarge the belt groove in the table. It even tips up for servicing like it always did. With the bigger pulley it make for less chance for the belt to slip since the original pulley is 4 inches and this one is 8. And my cost was 1 hour of time. Quote Share this post Link to post Share on other sites
Ole South Report post Posted March 1, 2015 More than one way to "skin a cat" huh? Am I reading your post correctly?!!? Your Handwheel pulley is 8" now??? Or your clutch pulley? Doing some research on the Singer 78 series and it seems there were about 13 or 14 variations of lifter and feed foot sets but so far I've only found 2 types available. I got a 5/16th's cording/piping set (no p/n) and what appears to be a canvas set (Seiko p/n 8021/8022) with my Consew. Both leave noticeable marks on veg-tan tho the canvas set is considerably lighter. Extrapolating the Singer parts lists; the 78-2/3 was primarily intended as a binder and upholstery machine tho there are fittings for binding leather shoe uppers and binding 2 layers of leather with another thinner piece that speak to us as leather workers. Quote Share this post Link to post Share on other sites
catskin Report post Posted March 2, 2015 In effect I now have an 8 inch hand wheel, the factory hand wheel is still there to put it back to factory state all it would take it loosening the set screw and pulling of the fly wheel. The only damage would be scuffed paint on the hub. The added weight of the compresser flywheel helps keep the machine turning steady at the slower speeds which doesn't hurt. I am inclined to believe mine was set up for upholstery since it sewed straight ahead with no changing of anything. My wife ,who has years of sewing in a garment factory says we should look into some other feet. The way it is the first job we did was sew a zipper into split leather chaps and it did it perfectly . My machine came with the left toe foot and of course the center foot that moves with the needle. There could very well be lots of other attachments that we still haven't learned exist. Quote Share this post Link to post Share on other sites
Ole South Report post Posted March 2, 2015 I have a list started but no luck finding any feet yet.. Look at the Consew(Seiko) 8021 and 8022 foot set I think you can still get them off ebay. Quote Share this post Link to post Share on other sites
