Leather stitcher speed - SPM

JTknives

JTknives

Joined
Jun 11, 2006
Messages
8,651
Im trying to get my champion 30 leather stitcher set up and besides needing a good cleaning and surface rust removal it needs a motor. I have a motor which is 2hp 1725rpm but the drive shaft on the base does not have a pulley. The stitcher has a 12" wheel and the drive shaft on the base has a 3" wheel which is 4 times reduction. Every one rotation of the 12" wheel is a completed stitch. So my question is how many stitches per min should I set this to for. I'm not doing production, just knife sheaths so I'm guessing slower is better. Just don't know say 2 stitches per sec is good/slow or if I need faster. Thanks guys.

Photo%20Sep%2004%2C%202%2027%2004%20PM.jpg


Photo%20Sep%2004%2C%202%2027%2015%20PM.jpg
 
My Pearson #6 (not a needle and awl, but the same sort of class of ultra heavy harness machine) was designed to be ran up to 300spm from either treadle or motor drive.
That said for sheaths I usually don't even pedal it, and just spin it by hand for better control.
The new chinese electric I had before it topped out around 250, and for sheaths wide open was FAST. Even if you're setting it up with a slip clutch (you can do single stitches with practice, but it's easy to loose control of without a lot of experience) I'd still probably shoot for the 100-150 spm range just to make it easier on you. Unless you're making saddles and harnesses, stitching speed isn't really a factor. Even turning a machine over by hand can do a typical sort of sheath is under a minute, and is way faster than a tippman boss sort of machine
 
While I've not worked with leather stitching machines, my sail making machine was fairly slow for good sewing and control. For sheath making, your idea of 1 to 2 stitches/min is going to be a good goal.
 
I used to have one just like yours. Mine had a 1/2 hp motor that probably ran 1750rpm. You can control the speed with the foot petal that presses the clutch plates together. I would guess I ran mine at maybe a stich per second.
 
I slowed my Con-Sew down to around 100 stitches a minute. I know you like to fiddle, so you might consider putting a 3Ph motor and a VFD on the stitcher.
 
Yeah it has a clutch with a foot peddle. I tryied to mount the 2hp baulder but the mounting brackets where way to far apart. I could mount one side of the motor base not not both sides. And it would kind jump when burned on. I then noticed my big DC geared motor. A quick measurement and the home spacing was perfect. It was like this motor was made for it. I went to the local farm store and looked for pullys. Thy sell hubs and wheels separate and you weld them togather. Problem is the shaft on the sewing machine is 1-5/16 and the only hub thy have that fits that is a hub to be used with sprocket. I would normally stay away away from chains becaus belts can slip if needed. But there is a round belt from the drive shaft to the stitcher. Also there is no way to move the motor up or down to tension the belt. The gear motor is 60rpm on the name plate so for 1 stitch a sec I would need to bump that speed up by 4x. I can control the speed of that motor in the future with a DC drive or a varac and a rectifier which I have. But I don't know if I can over drive it or if it would just be 0-60rpm. Here is a pic of it mounted.

Photo%20Sep%2004%2C%205%2045%2034%20PM.jpg


Photo%20Sep%2004%2C%205%2045%2043%20PM.jpg


Photo%20Sep%2004%2C%205%2045%2049%20PM.jpg
 
When I said one stich per second that meant that was what I was comfortable with. If I really stepped on the clutch lever it would stich so fast it was scary.
That machine has a real nice heavy wheel that you can just turn by hand and do a lot of stiching.
I used to have a owners manual with mine but when I sold the machine the manual went with it.
It looks like you need a bobbin, maybe you have one.
 
I dont want scary fast, I want slow and steady. I have the manual, it's a reprint that I ordered when I ordered my linen cord and needles.
 
If 1 stitch per second is enough momentum for the thing to work smoothly and punch through easily, I don't see how it would be worth messing with a solution to speed it up faster for sheath work.
 
I've heard a rumor that they factory test Cobra machines by stitching 1/2" ply...

You probably thought about this before you mounted the gear motor, but just in case you didn't,...
Gear motors can be picky about which side is "up". Mount them wrong side up and oil can start leaking out of the seals.
 
I had wondered about the mounting direction so I have left it like this to see if anything comes out. The oil (if you can call it that) is crazy thick. It's 140 gear oil I think off the top of my head. But my big concern is running this with a chain. Nothing in the shop raises my hackles like a chain drive. I don't know what it is about it, maybe I'm not famalur enough with them. But at the feed store thy have a 48 tooth for the motor and a 16 tooth for the drive shaft. That gives me a 3 times increase not the 4 I would need to get up to 1SPM. But I noticed on the drive shaft the pulley to drives the sewing machine is 3" but there is a bigger one right next to it. I think it's a 4" which would be a 3x reduction which would work with that sproket combo. I would just need to find a replacement round leather cord belt that is longer.
 
The feed store has weld on hub sprockets but not weld on hub v-belt pulleys? All our farm and barn type stores have both usually.
 
Thy have the weld on v belt pulleys but the hubs thy take are different. The hole in the pulleys are smaller and the hub thy take don't go up to the needed 1 5/16 for the drive shaft. But if I used a belt there is no way to tension it because the motor and mount can't be moved.
 
The round leather belting is available at McMaster Carr, and probably other industrial suppliers too. There's also a round PowerTwist "link" type belt available. It's 5/16" diameter which is a bit bigger than the 1/4" leather you usually find on sewing machines, but I used it on one of our sewing machines and it worked. I've got the regular PowerTwist belts on a lot of machines in the shop, you can adjust the belt length easily if moving the motor to tension the belt is a problem
 
Wow that is a beast. Good luck on the project. My heavy duty stitcher, (Ferdco 440 Pro R) has a servo motor with a multi position rotary switch for speed adjustment. It'll go from so slow it won't go to warp drive. I only use warp drive for winding bobbins. I find I use three clicks down from warp most of the time and occasionally four clicks. As to how many spm that is I have no idea. I would guesstimate 200-300 spm. Probably faster than most folks want to go but its what I'm use to. I've learned to use my hand on the wheel as a friction brake to slow it down some when getting to corners, sharp curves etc.
 
You must log in or register to reply here.
Back
Top