Stitches Per Minute
 

Being increasingly drawn to industrial machines, I'm interested in SPM as a comparison between machines and manufacturers. I have a modern Janome domestic (6500P) whose literature claims it is "blazingly fast" at 1000 SPM. Even running it at top speed, I don't find it particularly fast at all. My other domestics run similarly, some slower, some about the same speed. I have a Pfaff 30 that is fairly quick but I haven't tested it.

I'm currently considering a modern industrial that runs 5500 SPM. Others approach 6500 - 7000 SPM and changing the diameter of the motor's pulley (connected to the belt, controlling the speed of the drive shaft) can increase the speed further (or decrease; larger diameter == faster, smaller == slower).

When measuring SPM, does a manufacturer measure straight stitch only? Is the length of the stitch reduced from, say, 3 mm in order to perform a speed test? (I would imagine length would have a negligible effect on speed as long as the material can be fed accordingly -- if that is how the test is being performed).

In the little investigating I've done, both modern and vintage industrial machines are/were made to run above 6000 SPM and less than 2000. It depends upon the model and its intended purpose.

Is speed a meaningful measurement to you?

only when I am sewing 12 foot long pavilion seams or the like...

Our 241-12 is super fast. Heather almost never sews above 1/2 speed unless we are doing one of the aforementioned long seams.

Of course my preference is hand cranks and there the speed is me dependent....

I can't answer the testing questions but yes, speed and speed measurement is important to me. Machines that have .5 amp motors or less like the Featherweight and 319 are just so slooooow to use since I'm a speed demon. I would imagine the SPM for both these machines is pretty low on the spectrum. Similarly, my newest Bernina is supposed to be 1100 SPM and I out run the machine when doing FMQing, which can be irritating. So, speed/SPM
will be an important factor when I shop for a long arm quilting machine in the future.

I have used industrial machines. I like them for the power - speed is very nice, too. I miss it on the home machines BUT I don't max it out on an industrial - never - I seem to max it out on the home machines a lot though. I think you have to be very sure of what you are doing to use an industrial machine.

Steve, I have a 241-13 and it makes the tiniest stitches which aren't good for canvas, etc... otherwise I'd love it. I don't know how to make the stitches any longer - surgery maybe... there is some sort of limit on the stitch length in the wheel. I've considered just getting a different head on the rig but I love the machine - stitches not so much. I'm wishing I still had my 411 or what ever it was walking foot. That thing would sew through anything and not even hick-up.

I don't go by a number but by how fast it feels. European machines like the Bernina 830 and Necchi supernova have fast/slow switches, which is pretty useful. My Bernina 642-1 doesn't have a speed switch so it's hard to control for slow work (for which I use the nice slow 320K2).
My fastest machine by far is the 96K41. Great thing about industrials is that as you say you can change the diameter of the pulley (or even attach a faster motor) to change the speed. It's rated at 3,500 or 4,000 SPM which is plenty fast enough for me. Faster is directly proportional to probability of 16x231 through a finger (my mother did this and insists it wasn't a pleasant experience).

From what I've heard and read (and seen demonstrated on YT), servo motors have excellent speed control and are much quieter than the typical clutch motor.

I have one industrial (Adler Class 98 zig-zag) and it's currently rated at 2200 but can achieve 3000 with a different pulley attachment (that I don't have), this with the Mitsu clutch currently installed. It seems fast but the actual clutch is worn, meaning there isn't much speed control so this is undoubtedly influencing my perception.

A truly fast machine means work is done very quickly. It also means mistakes are made very quickly. Were I making draperies or working with larger amounts of upholstery, I'm putting the pedal to the metal. And I would think feeding scraps through a 7000 SPM machine just to see what happens would be fun. Making a pair of boxer shorts? Not so much.

I do. I have the instructions somewhere on my laptop at home. I'll shoot you the info tonight
(We had the same issue. the original setting was more like tear off perforation.....)

YIPPIE! I need that. Right now it is as big as it goes and and perforation stitches says it all. I love the machine but the perforation stitches not so much. Someone set mine up to do some slow speed as well as the high speed. I love the feel of it. I think I need a new leather belt on it some time. If I can get the stitches changed out it might be worth the money.

Speed isn't a consideration for me. I'm not a good enough sewer to go full speed on any of my home machines. Also, I do this for enjoyment, getting done quickly isn't the point. If I was in it for production and/or was able to sew faster then speed would be important to me.

On a home machine you can change the diameter of the motor pulley to a larger size to increase your speed but there will be a loss of torque as a result. It would probably be ok for most fabrics but you would probably have trouble with thicker fabrics like denim. Some of the domestic machines had 1.3 amp motors on them as opposed to the .6 amp motors Singer used. One of these slightly more powerful motors with a larger pulley might be a good combination on a home machine. There doesn't seem to be any middle ground between domestic machines and industrial machines, I would be concerned about trying to hook a domestic machine to an industrial motor. The extra power could easily cause parts breakage in a machine that's not designed for that much power.

I haven't had the opportunity to try an industrial machine. The old clutch motors-the motors themselves, anyway- should be nearly silent when they're running. I don't know if the clutches are noisy. The quietness of the old motors compared to modern universal electric motors is one of the attractions of old wood working machines(my other hobby).
Rodney

http://parts.singerco.com/IPinstManuals/241.pdf

page 10 of the PDF (numbered as page 16) shows and describes the process