Speed Reducer And Servo Motor?

[Wellington]

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. 

[CowboyBob]

1 hour ago, Wellington said:

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. 

On an  flatbed machine that sets in a table it is best to keep the reducer back by the motor so you can tilt the head back easily,the cylinder arm machine Northmount shows in his pic sets on top of the table & the style he made (which looks great) will work best on that type of machine(which is what we use too) you need to make one that looks like our box style so you can tilt the machine back as needed.

So we have the box style(for flatbed machines) on the left & SR2 (for cylinder arms) on the right in the pic.

Hope this helps you.

[toxo]

Nobody has mentioned installing a larger pulley to replace the hand wheel. I replaced mine with a 170mm pulley and it made a considerable difference before buying a servo motor. Speedwise, I'm now where I want to be apart from a sudden start which I think I can alleviate with the treadle position.

[Northmount]

2 hours ago, Wellington said:

I'm guessing your ratio is closer to 4:1 on your pulleys.

A 6" and a 3" pulley, so 2:1, plus the 3:1 in the geared servo.

I like the way the speed reducers Cowboy Bob has.  I may someday rebuild mine like the box that sits between the motor and the table.  Just have too many other projects to get done first!

As long as the pulley that drives your machine sits behind the centre line of the machine pulley, you can tilt the head back.  With my reducer in front of the leg, I can't tilt the head back without loosening or removing the belt.  Lesson learned! If I could, it would make it easier to tension the machine belt.

Tom

[Wellington]

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

 

 

Edited November 5, 2019 by Wellington

[Wellington]

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?

Edited November 6, 2019 by Wellington

[Wizcrafts]

I personally use a servo motor that lets me limit the top speed with a knob. When I sew small areas and vegetable tanned leather I limit the speed to a couple hundred rpm and sew very slowly; sometimes 1 stitch per second. When I sew upholstery leather, banners and long items, I crank it up to maximum speed and sew as fast as the machine wants to go (about 2000 spm). In upholstery, time is usually money. Just make sure you oil the machine well before running it flat out.

[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.

Edited November 7, 2019 by Wellington

[dikman]

Wellington, in round figures 550w is 3/4hp.

[Wellington]

Thanks, Dikman. 

Before I go and fab up a jackshaft arrangement, I'm going to try a smaller drive pulley (2.25" dia instead of 3.15" which should get me a max speed of 2000 spm at the machine head) and mount a longer lever arm on the servo motor's throttle arm (and/or maybe weld a shorter lever linkage arm to the pedal plate) and see where that gets me.

May also investigate trying this fix addressing the optical sensor in (some) servo motors:

 

Does anyone know whether my Consew Premiere 550 uses such an optical controller? Its symptoms sure seem to match those discussed in the video.

Thanks again. I'll report back with my findings for the forum.

W

Edited November 8, 2019 by Wellington