speed reducer

[Constabulary]

34 minutes ago, Sticks said:

 yes I agree about the servo,thing is I went to the shop in london to try out the one I can afford and it cuts in at 200rpm lowest setting.Too fast.

My servos also run at 200rpm min and thats what the speed reducer is for - reducing speed!!!! RPM on the motor does not mean stitches per minute except you have a 1:1 ratio (75mm pulley on hand wheel and 75mm pulley on the motor). With a speed reducer with 1:3 ratio you reduce the speed by 2/3 and that would be 1.1 stitches per second.

200 rpm / stitches per minute : 3 = 66.666 rpm / spm : 60 sec. = 1.1111 stitch per second

And when you add a smaller pulley to the motor its even slower.

You don´t have to cut the table you can put the reducer under the table. But you have to reposition the motor. Again - check the forum for Speed Reducer - almost everybody is using them and there are dozens of different solutions - thats the way to go!

This is how it looks on my table and and underneath.

Edited November 11, 2016 by Constabulary

[dikman]

Exactly which model servo are you looking at? My servos can be set to much slower than 200 rpm.

[Evo160K]

If you're wanting to slow down a digitally controlled servo motor without having to us a speed reducer, you might want to check the video in the first link.  It was originally posted in the LW topic, "Getting Control of Your Servo".  You can see how well that modification worked on my servo by checking the video I posted in that LW topic.

The video in the second link explains how to slow down a digitally controlled servo motor with a needle positioning system.

http://www.swflholsters.com/358/sewing-servo-motor-diy-smoother-speed-control-mod-paper-gradient/

http://www.swflholsters.com/434/sewing-servo-needle-positioner-eps-speed-mod/

Edited November 12, 2016 by Evo160K

[Constabulary]

I see no link but that does not work with servos from College Sewing as they have an magnetic accelerator unit.

[Constabulary]

I´m 99% sure it has a magnetic controller. This one also starts at 200rpm you have noticed that, right?

[Wizcrafts]

Sticks;

Have you read about the Family Sew servo motors? I have to believe that somebody in the UK sells this brand. This motor starts spinning at 1 rpm if you so desire. It doesn't have a lot of torque at the slowest speeds, which is why many users add a speed reducer. I have this motor powering a big Cowboy CB4500, through a 3:1 speed reducer. I can sew 1 stitch every 8 or 9 seconds if I had reason to do so. Once in motion it penetrates the thickest stack of leather (unless the belts slip).

The same motor without a speed reducer powers my long arm walking foot machine. I can hold it at a steady pace of about 1 to 1.5 stitches per second at the low end, with the speed limiter all the way down to 350.

[Wizcrafts]

20 minutes ago, Sticks said:

So the part is called the bobbin case opener. The is preventing the bobbin assembly from rotating fully.

 

Loosen the screw on the right end of the Latch Opener lever, push/pry the opener to the left for more clearance, then tighten down the screw. It should just pull back on the boon case as the top thread comes down and off the needle. Then it should begin to move left and release the case to pass the top thread as it goes over and under the bobbin case.

[SARK9]

When changing the stitch length on this type machine, I always unthread the needle before rotating the handwheel to engage the adjuster stop, as this prevents an occasional tangle in the hook area like you may have experienced.

Its the left button on the bed you depress to adjust the stitch length, the other one (safety clutch) will completely stop the handwheel from moving backwards, and will only ratchet when turning fwd.

 

-DC

[dikman]

16 hours ago, Constabulary said:

I´m 99% sure it has a magnetic controller. This one also starts at 200rpm you have noticed that, right?

You made the same mistake I did at first reading - it's 200 spm, not rpm, which equals about 3 rpm. Quoting spm, however, is meaningless as it all depends on the size of the pulley fitted to the motor and the size of the handwheel pulley. If it's a misprint, and is supposed to be rpm, then it's not a very good motor as a digitally controlled servo should be able to get much lower than 200 rpm. Really need the manual to work out what they really mean.

[brmax]

If I were not using a reduction setup, a small pulley is required in my opinion. Also a cogged belt may be beneficial in the smallest of pulleys.

I have seen on the net pulley calculation size programs and their rpms, may try to google and put your measures in!

Floyd