A little help with Weaver Cub machine

[Usmc42]

Hey everyone!

This is my first topic and I’m sorry that it’s a request for help. I recently got a Weaver Cub machine and went right to work sewing some scraps to get a feel for it.

I started with some an old grey Horween leather I had from a project I abandoned since it had multiple layers of 3-4oz leather. I used black 277 thread on the size 200 794S needle that comes with the machine.

The problem is the lock knot is inconsistent throughout the piece without changing tension. I know this is a top tension issue but in order to avoid a top knot the manual says to decrease tension. My machine is already at the loosest tension. 
 

I then went back to the 207/207 thread that came installed on the machine (all white thread shown in pics below) and got a few more practice pieces to try and tune things up. Same issue. Seems to be regardless of tension input. 

Haven’t tried switching to a smaller bobbin thread (currently 207 top/bottom like the machine arrived). Don’t know if this would really make a difference. 

I know Weaver has excellent customer service but I am in Japan on a military base so I would have to stay up till 1100pm to get them. The few times I have tried that late the machine support folks weren’t in. Still plan to get a hold of them soon by pre-coordinating in email but thought I’d ask to see if anyone is having/had the same problems. 

I’ll post some photos in a few minutes when I can find an app to host them.

Thanks,
Gabe

 

[Usmc42]

https://ibb.co/r54rZXT
https://ibb.co/6vKf1jr
https://ibb.co/B4y9CrB
https://ibb.co/m4PHNN8
https://ibb.co/RDQQgtk
https://ibb.co/Dgnkky8
https://ibb.co/41sGW02
 

Can’t seem to upload photos. Says they must be under 1.46MB so I was forced to post links

I have a bunch of test pieces. The grey wallet I started with 277 black thread. Was having all sorts of problems with it including missed stitches. I went back down to the supplied 207 thread for all the other test pieces. 
 

as you can see the lock knot is inconsistent. For the most of the test pieces the tension is all the way out - or as loose as it will allow. I have tried adjusting tension and playing with the spring in between test pieces but no avail. This is about a 1/4 of the test pieces I’ve ran through. I’ve adjusted bobbin tension in slight increments but no avail (it’s back to original tension now).
 

I am using combinations of 9oz + 4oz, 9oz + 9 oz, 4 x 4 oz, etc. usually adding up to 12-18 oz. All 207/207 thread with a 200 794S needle (except the black thread project). Machine is well oiled/greased.
 

I’m at a loss here. Even with the same settings the lock knot fluctuates. 

[Constabulary]

Are you using a round point needle or a leather needle? Have you tried a 1 size thinner thread on the bottom or maybe a 1 size larger needle?

[Usmc42]

I’m using a 794S chisel type cutting needle which is what came with the machine. Machine also came loaded with 207 thread top/bottom. I don’t have smaller thread but I have bigger so I could try loading 277 into the top with 207 in the lower. That’s still in spec for the 200 needle. The black thread pictured is 277 but I also used 277 in the bobbin - So haven’t tried two different sizes upper/lower yet. I’ll give it a shot!

[Cumberland Highpower]

39 minutes ago, Usmc42 said:

I’m using a 794S chisel type cutting needle which is what came with the machine. Machine also came loaded with 207 thread top/bottom. I don’t have smaller thread but I have bigger so I could try loading 277 into the top with 207 in the lower. That’s still in spec for the 200 needle. The black thread pictured is 277 but I also used 277 in the bobbin - So haven’t tried two different sizes upper/lower yet. I’ll give it a shot!

Hmm...

Well it's not all that uncommon for a threaded needle type machine to have an issue with the lock like that.   In the past when I first started I had issues with Adler 205's and a Luberto Classic doing the same thing.  The problem is that when you have a spring loaded tensioner (No brakes) and a threaded needle that's how it will be.   You'll need to use a smaller thread.   277 and even 207 is too large for a machine stitched wallet in 3/4oz leather.

go to a smaller thread, 138 for example with the matching needle.   You'll have much better looking stitches.   Don't try to exceed the design of your machine.   What your using would be better suited to sewing a saddle or harness.

I made a wallet for myself once of 3/4oz bridle and I stitched it on a Randall. (Hook and awl) in 277.  I was able to hide the locks, but just barely.  A hook and awl machine with brakes can be tuned just right to hide a lock in such large thread in such thin leather, but not a threaded needle machine with spring tensioners....

One small thing that might help out if you're dead set on using 277 and a large needle is to make sure your thread is lubed.  Not many threads come pre-lubed.

Having your tension set so low on the top is probably what is causing your loose thread on the underside.

 

 

Edited January 18, 2022 by Cumberland Highpower

[chrisash]

Have you tried tightening the bobbin tension or leave as it is and use the next size needle up.

 

[Wizcrafts]

First, is the thread coming off the spool smoothly, without getting hung up along the way? If the thread is hanging up between the spool and top tensioner, your tension disks will always be unpredictable. If there is anything amiss in the top thread feed, fix it.

If the top thread is feeding smoothly, tighten the bobbin tension enough that you also have to add more top tension.

Also, make sure the top thread stays inside the tension disks and doesn't lift out as you sew. That is instant zero tension.

[Hags]

And be real sure the bobbin is loaded correctly. I've had machine for a while now but that was one of my earliest mistakes. It makes a difference which way it comes off the bobbin.