slow stitching speed

[BillyR]

buying a new machine and was wondering how to relate rpm to stitches per minute..if with a reducer the machine does say 100rpm slowest speed, does that mean 100 stitches per minute ?thanks

[garypl]

Should depend on sizes of the pulleys.  Best to go test the machine, if possible, so you can decide if it will sew slow enough for you.  I have a CB4500 and my normal speed is about 50 stitches per minute.

Gary

[Joon1911]

Billy, I know the following doesn’t actually answer your question but I think it relates.

I have a standard setup Cobra Class 4 which is basically the same thing as Gary’s CB4500.  If I recall the servo motor doesn’t tell you rpm in the settings, it goes from 1-25 maybe?  It’s been so long since I messed with it.  For the first month I set it at 3 or so until I gained comfort. That setting at its fastest was maybe 60-70 stitches per minute if I recall correctly.  Upon the suggestion of a mentor, I changed that setting to the highest and have never looked back.   I can stitch as slow as I want, maybe 1 stitch every 2-3 seconds to full bore just by the pedal engagement.  

I’d suggest this to anyone;  get used to controlling your motor not letting it control you. I wouldn’t want to switch back and forth all the time whenever I wanted to sew a belt or strap or fill bobbins.  That’s lost time and productivity.  

[garypl]

27 minutes ago, Joon1911 said:

Billy, I know the following doesn’t actually answer your question but I think it relates.

I have a standard setup Cobra Class 4 which is basically the same thing as Gary’s CB4500.  If I recall the servo motor doesn’t tell you rpm in the settings, it goes from 1-25 maybe?  It’s been so long since I messed with it.  For the first month I set it at 3 or so until I gained comfort. That setting at its fastest was maybe 60-70 stitches per minute if I recall correctly.  Upon the suggestion of a mentor, I changed that setting to the highest and have never looked back.   I can stitch as slow as I want, maybe 1 stitch every 2-3 seconds to full bore just by the pedal engagement.  

I’d suggest this to anyone;  get used to controlling your motor not letting it control you. I wouldn’t want to switch back and forth all the time whenever I wanted to sew a belt or strap or fill bobbins.  That’s lost time and productivity.  

That’s good advice Joon - now that I have been using my machine for awhile I will see how I do with bumping up the speed dial!

Gary

[Matt S]

11 hours ago, BillyR said:

buying a new machine and was wondering how to relate rpm to stitches per minute..if with a reducer the machine does say 100rpm slowest speed, does that mean 100 stitches per minute ?thanks

Yes the RPM of the balance wheel on the machine = SPM. Is that 100RPM what's quoted on the machine or the motor?

To calculate this from your motor RPM you have to know the ratio of the pulleys in your powertrain. A lot of upholstery-weight machines have around a 80mm pulley. So with a 40mm pulley on the motor (the smallest you can easily get) you're only getting a 2:1 reduction. The super-cheap servo on my upholstery-weight cylinder-bed machine starts at 500RPM so I had to fit a 3:1 reducer to get it under 250SPM. With the reducer I have it down to about 80SPM, which is pretty slow. Bonus with a reducer is that you get an equivalent boost in torque (punching power).

I find this calculator handy: https://www.blocklayer.com/pulley-belt.aspx

[Wizcrafts]

1 hour ago, Matt S said:

The super-cheap servo on my upholstery-weight cylinder-bed machine starts at 500RPM so I had to fit a 3:1 reducer to get it under 250SPM. With the reducer I have it down to about 80SPM, which is pretty slow.

You might want to think about changing servos to a Family Sew 550. I have that motor on my CB4500 and on my long arm Singer 139 walking foot machine. It starts at zero rpm and slowly increases with pedal motion. There is a knob on the front face of the motor that limits the top speed, or not. There are no sudden changes in speed.

[BillyR]

thanks boys for your responses..I ordered a techsew 2750 with servo and speed reducer so it sounds like I can be a stitch a second sewer with no problem..I just wasn't sure if the servo alone would let me do that so I added the reducer to make sure. I hope the high speed is still useable..As you can see, I know nothing

[JLSleather]

I never understood (and still don't) what is the perceived value of going SLOWER.  I've actually seen videos and articles of people going on about how SLOW they can sew.  Then with the other side of their mouth tell you it's expensive because it takes time!  So, some  amusing thoughts ...

• Would you pay more for a flight from Chicago to LA if the pilot agreed to go have as fast?
• When those boys show up to plow the snow from my drive, should I pay more to the fast guy, or the guy who takes a while?
• Does pizza cost more if it's here in 31 minutes or MORE?

Okay, that was only moderately fun.  But if you want to sew, including leather, ask Wiz where that video of his went -- where he was sewing straps (gun slings?) on a National machine... took almost as long as typing this (but not quite).

I have a pedestal machine, that i WOULD run up faster, except the base just isn't sturdy enough.  Servo set about 20 or so - for those who know what that means - but when you run it up a bit it isn't stable, even with the stand adjusted most of the way down.  Faster it goes, more it rocks... despite way too much time spent leveling, and leveling, and releveling ....

FORTUNATELY, if a speed reducer can be added, it can also be removed.  I DO understand not wanting to ruin a project you spent 10 hours tooling, but a plain strap of leather is what ... $10?  $15?  

 

[Sonydaze]

4 hours ago, Joon1911 said:

Billy, I know the following doesn’t actually answer your question but I think it relates.

I have a standard setup Cobra Class 4 which is basically the same thing as Gary’s CB4500.  If I recall the servo motor doesn’t tell you rpm in the settings, it goes from 1-25 maybe?  It’s been so long since I messed with it.  For the first month I set it at 3 or so until I gained comfort. That setting at its fastest was maybe 60-70 stitches per minute if I recall correctly.  Upon the suggestion of a mentor, I changed that setting to the highest and have never looked back.   I can stitch as slow as I want, maybe 1 stitch every 2-3 seconds to full bore just by the pedal engagement.  

I’d suggest this to anyone;  get used to controlling your motor not letting it control you. I wouldn’t want to switch back and forth all the time whenever I wanted to sew a belt or strap or fill bobbins.  That’s lost time and productivity.  

I agree, watching your machine amble down the easy parts to sew is a waste of time.  I can't envision someone wanting to pay more for your product just because you sewed it really slow.  

[Hockeymender]

Sewing speed is dictated by what is being done. I see all this about “why would anyone want to slow things down?”. Around here everything is sewn at the slowest speed possible. Precision work requires it. Hockey glove palms can be quite tricky to get placed and sewn properly, and if the machine was zipping along it would be a complete disaster for sure. Just my 2 cents worth.