Missing The Loop

[catskin]

Please can anybody help me. I am having trouble with my machine ( Adler 20-2 ) not forming a good loop for the shuttle to catch some of the time. It will make the most perfect stiches for a while, some times 2 or 3 feet then start missing some times as many as 10 in a row.

This is with 346 bonded nylon thead on leather.

Here are what I have tried.

Changing shuttle. Seemed to have fixed it , went back next day and was back to same problem.

Turned the needle slightly one way and the other , no help.

Changed needles to try different sizes. !80, 200, 230, 250. no difference.

Changed feet, No help.

Changed to diferent spools of thread, No help.

Adjusted needle bar slightly up and down , no change.

Tried sewing different kinds of leather, no real change. Different thicknesses from one ply of about 8 oz. to 5/8 thick (4 plys various thickesses)

Most of the above seemed to make a bit of difference but only for a short time.

Checked for loose parts.

Can't find any parts that seem to have noticeable wear.

Now can these cause this kind of trouble.

Worn hole in needle plate?

Dull point on shuttle?

Worn shuttle track?

What have I missed?

I've had this machine for quite a while though it never got much use, its always been prone to this sort of thing and at times it would get going good without my knowing what I did to make it better.

I doubt it can be timing , if it was it wouldn't make perfect stiches for a while then start missing.

Any suggestions greatly appreciated.

[Wizcrafts]

Needle getting deflected by the layers of leather and heat from friction?

Check spring adjustment (more or less travel)? This affects the size of the loop.

Worn pickup point is a definite possible maybe.

Does your Adler use spacer shims in the shuttle? If so, does the shim match the needle size?

Is there any side slack in the shuttle, that coulds cause the point to miss the loop?

[catskin]

Needle getting deflected by the layers of leather and heat from friction?

Check spring adjustment (more or less travel)? This affects the size of the loop.

Worn pickup point is a definite possible maybe.

Does your Adler use spacer shims in the shuttle? If so, does the shim match the needle size?

Is there any side slack in the shuttle, that coulds cause the point to miss the loop?

Thanks Wiz.

First I have this old machine slowed WAY down so heat is not likely, deflection maybe. but on one ply ?

Next I MUST check this spring adjustment. Is this the one between the tension roller and the pullup lever?

Pickup point seems okay BUT.

No shims since I have it. I have 4 shuttles and they have a machined spot of varying sizes just back of the point on the outside edge that I THINK might have something to do with telling you which one should be used for possibly different needle sizes.

Side slack seems very small. In fact not noticeably more then on the new Cowboy 4500.

The point does not really miss the loop but rather pushs it forward then slips past.

I can see what is happening by taking of the plate to the right of the needle. When the loop forms it doesn' always stick out straight from the needle but twists slightly forward ( the direction the shuttle is going)

Gotta go check that spring.

Edited November 24, 2011 by catskin

[Wizcrafts]

Thanks Wiz.

First I have this old machine slowed WAY down so heat is not likely, deflection maybe. but on one ply ?

Next I MUST check this spring adjustment. Is this the one between the tension roller and the pullup lever?

Pickup point seems okay BUT.

No shims since I have it. I have 4 shuttles and they have a machined spot of varying sizes just back of the point on the outside edge that I THINK might have something to do with telling you which one should be used for possibly different needle sizes.

Side slack seems very small. In fact not noticeably more then on the new Cowboy 4500.

The point does not really miss the loop but rather pushs it forward then slips past.

I can see what is happening by taking of the plate to the right of the needle. When the loop forms it doesn' always stick out straight from the needle but twists slightly forward ( the direction the shuttle is going)

Gotta go check that spring.

Yes, the check spring goes between the bottom disks and the take-up lever. It sounds like you need to reduce the travel of the check spring, so the loop forms sooner. Also, change the path the thread takes from the thread stand. Try going through a top hole, around the post, then out the bottom hole, on to the top tension disks.

What brand, system and number needles are you using with what thread sizes? Too big of a needle will allow the loops to collapse sooner than otherwise.

[catskin]

Thanks Wiz.

I tried changeing the travel on that spring,from maximum to no travel and several in between, no improvement.

This machine takes the same System 794 needle as the 4500 Cowboy, I am using schmetz I even tried some that Bob sent with the Cowboy.

This machine does not have a post with holes to run the thread through.

I know 180 is on the small side for 346 thread and 250 might be on the big side but the surpriseing part is they all do the same thing . I would have expected either better or worse with changeing size but there isn't any.

I kinda hope Bob or someone who has seen a 20-2 might see this . In case they have some quirk that is unique to them.

[Wizcrafts]

Please retime the machine by retarding the hook a few degrees. If necessary, lower the needlebar to place the loop well into the pickup point, and above the eye.

Make sure that you time the machine in forward and reverse, at the same stitch length. Timing is more critical for long stitches than short, when reverse is used.

If this doesn't improve the situation, change the path of the top thread so it is more inline than otherwise.

Are you using typical left twist bonded thread? Is it coming off the spool easily, or with binding?

[catskin]

Thanks yet again Wiz for your time and advice.

Now after all I said about looking for loose parts I realize I missed one. I tended to be looking at the bottom and finally found that the set screw that holds the top cam that drives the needle bar and takeup lever plus foot lift onto the main top shaft was very slightly loose. Which allowed it to move a few thousandths back and forth on the shaft. It has timing marks on the shaft and cam so I know it is right now. This seems to have all but fixed the problem. Now it only misses the loop on very thick ( near its limit ) but changeing to a thicker needle might help that.

If anybody out there knows what those marks on the shuttles mean I sure would like to know. If as I suspect they indicate which shuttle should go with which size needle it would help set things up right the first time.

[catskin]

Well I have it doing good on the thinner stuff, but onthe thicker stuff it still skips. What I see it doing is forming loops on both sides of the needle rather then just on the right side . What can cause this? This makes for a small loop for the shuttle to catch.

And there is sometimes deflection on the needle that helps make it miss the loop. If I push the work to the right it catches the loop better. There is not much side play on the shuttle , in fact it almost crushes the thread on the back stroke as the needle is coming down, and brushes the needle as it comes forward to pick up the thread with no leather or thin leather in it.

The hole in the needle plate looks rather big (worn ) can this be the cause?

[Wizcrafts]

Well I have it doing good on the thinner stuff, but onthe thicker stuff it still skips. What I see it doing is forming loops on both sides of the needle rather then just on the right side . What can cause this? This makes for a small loop for the shuttle to catch.

And there is sometimes deflection on the needle that helps make it miss the loop. If I push the work to the right it catches the loop better. There is not much side play on the shuttle , in fact it almost crushes the thread on the back stroke as the needle is coming down, and brushes the needle as it comes forward to pick up the thread with no leather or thin leather in it.

The hole in the needle plate looks rather big (worn ) can this be the cause?

Get you some Schmetz leather point needles and see if they cure the bad loop problem.

What size needle and thread are you using right now?

[CowboyBob]

Hello,If it's making a loop on both sides I would say you need to advance the timing alittle,it's trying to make to big of a loop before the shuttle gets to the needle,also on the thicker leather you might need to tighten up the foot pressure so it can hold the leather down.

Bob

[catskin]

Wiz.

I am using Schmetz 230 leather point needles that Bob sent with the CB 4500 and 346 bonded nylon thread.

I have also tried 180 and 250 sizes all schmetz leather point.

Bob.

Where do you adjust the timing? I have examined this machine everywhere I can find and except for moving the needle bar up and down I can not find anywhere to change the timing. On the bottom every part has a pin through the shaft plus a set screw or so it seems to me.

As for foot pressure I have it as tight as it can go and still be able to turn it to lift the foot between stiches. I have tried adjusting the foot pressure to varying amounts.

Can you tell me what the reason is for the bevels of different sizes that are machined just behind the pickup point on the shuttle? I have 4 shuttles and the bevels are different on each. Has it something to do with which shuttle should be used with which needle and thread size?

[CowboyBob]

Ok, so the shafts are pinned,on the far right where the rod comes down to make the shuttle go back & forth sometimes this nut can loosen & the bolt can back out making play in the shaft.

[catskin]

Thanks Bob.

I will check all the bolts.

This being a bottom feed jump foot machine. After doing some more testing it seems like maybe the leather is getting pushed down into the slot where the feed dog goes and that is causeing the needle to deflect some times. Also will try to put the stop behind the foot so it works in sliding mode rather then jumpng mode. I am starting to think it has to do with how the foot and feed dog work together in gripping the leather or perhaps not holding it steady enough at the critical time.