Wellington

Thanks for the information, Wizcrafts. Now you've got me thinking. I may be able to get away with no jackshaft – just replace my 3.5" driving sheave with a 2.3" sheave, which at 3450 with a 4" driven sheave should give 2000 rpm at the machine head. (Assuming my math is right.) So if I wanted to get, say, 60 spm at the machine, I could dial the motor down to about 100 rpm ... do you think 100 rpm on a Consew 550 will give me the punch I need for say 1/8" to 3/16" leather at 1 stitch per second without too much slippage at that 2.3" diameter driving sheave? I'm just a hobbyist/beginner, really, at this point, so I don't really care about going super fast ... more concerned about having good torque at low spm speeds so I don't have to horse it with the handwheel...or dial up the speed dial and then have it run away...on this motor, at least, there's seems to be about 1 second's worth of angle difference on the speed adjustment knob between "manageable" and "holy cow, LOOKOUT!" and the remaining 95% of the adjustment dial is useless. (At current gear ratio, max motor speed should give 3000 spm at the head, whereas Adler recommends max of 2000 spm for that machine.) Sorry for the dumb newbie questions, and thanks again for your help.

I'm figuring out all my sheave sizes to get speed reduction right and had a question for you folks, since I don't want to reduce the gear ratio too much nor not enough. This Adler 67-GK373 will be used for upholstery, some heavy textile sewing, and maybe 15% leather work, most of it lightweight. Rig has a Consew 550 motor w/ max speed of 3450. Consew claims it's 3/4 hp (though I'm not sure how you get that from 550W). According to mfgr, this Adler 67 has max speed of 2000 spm, but I can't imagine ever wanting to go over 1000 spm. So I'm considering gearing my reduction jackshaft to give 1000 rpm at the machine when the Consew is WOT at 3450. Does that sound reasonable to you folks? I'm accustomed to fairly slow machines (other machines are a Singer 201-k3 and a Pfaff 130-6) so even 1000 spm is cooking with acetylene, as far as I'm concerned. TIA for any insights. W. ETA: For what it's worth, right now, drive sheave is 3.5" and driven is 4" so I would need a 3:1 reduction from that to get to my current target. Will that give me enough oomph at low speed for the occasional heavy leather job, or should I reduce it further?

Thank you, CowboyBob and Northmount and Toxo. This is all great information, particularly those photos. I appreciate your help.

Thank you, sir! On second glance, I'm guessing your ratio is closer to 4:1 on your pulleys. Is there anything, in hindsight, that you would do differently or improve with your setup? I will probably do something quite like yours. (Still getting my Adler 67 up and running at this point...) Thanks again.

Tom (or anyone else who might know): Where did you find the sheaves for this? I might want to do a jackshaft speed reducer for my Adler 67 / Consew 550, but I'm not sure where to find sheaves at a decent price. Surplus Center, maybe? Ebay? I'd try Grainger or MSC but suspect they're $$$$$$$$ there (like most things)... Also, what kind of reduction are we generally looking for here? Something like 3-to-1 I'm guessing (3-1/2" to 10-1/2" for examaple)? Thanks in advance for any help. W.

Hello, all, New member here. I thought about starting a new thread, but decided to tack onto this existing thread to make things easier for searchers in the future. I'm considering driving several hours to look at a Pfaff 138 here https://richmond.craigslist.org/art/d/sewing-machine-industrial/6770955579.html Spoke to the seller, and he said the brass plates on the machine read "138-6/21-BS" and "139936." In my research, I found that Pfaff 138s come in several variants. I guess the "A" variant is for lighter fabrics and the "B" is for medium weight fabrics. Question: Would the "B" at the end of the model number on the brass plate ("138-6/21-BS") indicate that this is a "B" version? What is the difference, physically, between the "A" and "B" versions? Question: Would I be able to use heavier needles on this machine? I got the feeling that one could use needles up to about size 120 or so on the Pfaff 138, but the manual suggests that 100/16 would be max on the 138 "B" variant. Question: Could I change the needle type used on this machine, possibly by changing or modifying the needle bar? The seller said it takes 438kk needles (and one website says this is equivalent to 265KK), but I see that these needles aren't very common (or cheap). If possible, I would like to switch to the common 15x1 system used on home machines like my Pfaff 130. (I was surprised that not all 138s use 15x1 needles, considering that the 138 and 130 share the same hook, bobbin case and bobbin, etc...) Machine would be used for boat canvas, light upholstery, garment construction, garment alterations and repairs, etc. I've been fairly happy with my Pfaff 130 for these purposes, but would like a bit more power, as well as the knee presser lifter and foot-pedal reverse (I'm actually thinking of trying to rig a knee lifter on my 130...I can tig weld and fabricate...) (Also considering trying to find a Pfaff 545 for the heavier jobs –such as heavier canvas, webbing and truck/boat upholstery – and selling off my Singer 201-3, whose capabilities would be covered by the Pfaff 130 or 138 ... I don't have room for a whole bunch of sewing machines. If I could keep it to two – maybe a Pfaff 138 and a Pfaff 545 – that would be ideal...) One last question: I always heard that the Pfaff 130 contained no plastic parts at all, but I discovered that there is a white plastic (nylon?) gear in the machine (I think it has something to do with the zig zag) and I have read that the hook is driven by some kind of "composite plastic" gear ... does anyone know whether the Pfaff 138 has any plastic parts prone to breakage? Thank you in advance for any help. Wellington.