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Union Lockstitch Sewing Machines, Why?

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So somehow I got down a rabbit hole and started reading about these machines.

Whats the advantage to them? Why would I, or someone, want a union lock over a standard sewing machine? 

 

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I do not own one but read a little about them since old time holster makers swear by the old lock stitch machines. This is a hook and awl machine. As far as I can tell, this uses an awl moving downward to pierce the leather and advance it. Then a hook comes up and grabs the thread, pulling it down to form the loop.

The advantage is supposed to be that the awl makes a smaller hole relative to a needle, and there is no presser foot to scuff the leather. People who use these machines say these advantages are functional; IE a stronger stitch and stronger leather versus a walking foot machine. The other side will contend that the final stitch is the same and the differences are cosmetic.

Both sides agree that these machines are loud and finicky. Parts, if available, are expensive. If not available, need to be custom made. I know of one holster maker who almost went out of business waiting for his hook and awl machine to be fixed, then finally broke down and bought a walking foot machine to complete his orders.

I am sure several people here can give you more details or even some first hand experience with these machines.

 

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The Union Lockstitch machines were first unleashed upon the Earth around 1898, plus or minus a few years. The oldest one I owned was from 1910.

These beasts weigh 400 pounds on a table and with a continuous run motor. The head alone weighs 250 pounds.

The feed is via the needle. The awl comes down and pokes a hole that is 1 size larger than the needle. The needle comes up into the poked hole and the presser foot lifts. As the foot lifts the needle advances the leather. At the end of its travel a looper feeds the thread into a barb in the top of the needle. The needle pulls the thread down, then the hook lifts it off the barb and takes it around the bobbin.

The default setup allows for constant stitching at 3/4 inch. It can tension any thread size as long as you have the proper needle and awl sizes. The bobbins are about 2.5 inches in diameter and 3/4 inch wide at the center. There are all mAnner of presser feet and throat plates available for the ULS.

The maximum speed of the machine is 800 stitches per minute, or 15 per second. Running flat out on a long harness tug will shake the building. The moving parts slap and bang as you sew. This is not a quiet machine, nor one for a timid or inexperienced sewer. Simply moving it across the floor can throw it out of adjustment if everything isn't tightened down properly.

A properly adjusted ULS machine sews the tightest stitch of any harness stitcher. The maximum stitch length is 4 to the inch. The bottom appearance is very close  to the top, but not exactly the same. The machines can sew through plywood. They are not much good on anything woven, like webbing and have a problem sewing Biothane straps because the holes tend to heal as the awl comes up.

I have owned two and am currently involved in fine tuning one for a new friend in Michigan.

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They are a beast.  I have made replacement parts for the bobbins and other odds and ends.  The Amish shop I learned a lot at had two of them, powered by air motors.  The young guy told me that Amish machines sewed to beat Hell!  He had a wooden guide setup for doing tugs and ran the machines flat out when he could.  Building didn't quite shake, but it was close.  Nicest stitch you want to see.  Hot wax, propane flame.  The girls there used them for collar work, the guys did harness work.  They had the setup to do hidden stitches, in the slit made by the old Gomph hand tools.  They hooked me on Gomph and HF Osborne.  Old cast iron crupper stuffers and six station crupper molds.....fun times.

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1 hour ago, MikeRock said:

They had the setup to do hidden stitches, in the slit made by the old Gomph hand tools.

My first ULS had every conceivable foot, including one with a blade on the bottom front. It cut a channel in front of the awl and the stitches were perfectly placed in it and were concealed. My favorite feet were stepping feet, but only on straightaways.

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