Saddlers Clam - leather holding system.

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Saddlers Clam - leather holding system.

Postby gavin » Sun Mar 18, 2012 10:39 pm

When sewing leather, it can be award to align the edges and then hold them whilst punching awl-holes and passing needles through the leather.
Enter the Saddler’s Clam. Not rocket science to make and usually 75 mm wide and not 45 mm wide as you see here. I made this from 2 lengths of 45 x 8 mm round-edged softwood of 87 cm, with 2 more pieces approx 30 cm as spacers to separate the 87 cm jaws.

You sit and grip the clam vertically between your knees.

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Detail of the jaws – you need to chamfer the ends and make sure the 2 jaws meet evenly.
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Here is the clam held between my knees gripping 2 bits of leather.
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Re: Saddlers Clam - leather holding system.

Postby Davie Crockett » Mon Mar 19, 2012 9:42 am

It also helps (If you want a neat seam) to have a "Pricking iron"
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I used to be a coach trimmer/upholsterer and part of my apprenticeship was making hinge stop straps for the old 1st class carriages using a clam, pricker and flax thread with a double needle and awl.

Method: (I hope I'm not teaching you to suck eggs)
A double needle is literally a needle at both ends of your thread. Generally you work with 4ft lengths of thread at a time. Thread the needle and dress the thread with soft wax (the end then sticks to the main part of the thread).

After marking, pricking and clamping, your first stitch should equalise the thread so there is the same length either side of the work piece. When sewing first use the right, then the left, apply tension after every double stitch. Get used to repeating this as it keeps the stitch even and neat. When you come to the end of your run, overlap or back stitch 3 or 4 stitches and trim the thread.
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Re: Saddlers Clam - leather holding system.

Postby timbadger » Mon Mar 19, 2012 10:11 am

Davie,
With the pricker is it only to mark or to cut the holes right through? If its the latter presumably thats done before its put into the clamp, by means of a mallet onto a corkboard or something similar?

To downsize a bit, if trying a few sheaths etc or to try your hand before purchasing more, a fork can be used to get equal stitch spacing and then a small awl to make the holes. I believe that a diamond shaped ones are considdered propper with the holes cut so that the thread does not pull along the line of the cut (ie the smaller angled points), however round holes in wet leather work well. The leather being wet and pushed open by the round hole shrinks back around the thread and makes a very tight seam (watertight with a little care) although wet leather may get marked in the clamp? Ive seen them with leather protectors inside the jaws to help lessen this but havent tried them yet.
Pricking wheels are good too, and getting and even stich makes a lot of difference to the look of whats being made.
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Re: Saddlers Clam - leather holding system.

Postby Davie Crockett » Mon Mar 19, 2012 10:34 am

The pricker cuts the top leather right through, this is then a guide for the awl to puncture the back leather. You are right about the pricker. It cuts a diamond shaped oblique stitch line like this ////////. Your "face" stitch should run from the top of one slot to the bottom of the next. That's why you always do right stitch, left stitch & tension for every stitch.
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Re: Saddlers Clam - leather holding system.

Postby ToneWood » Thu Mar 27, 2014 2:44 pm

Have just started making a leather clam and came across this thread while researching it - should have known somebody here had done this before! An interesting design variant I came across stays closed by default and is opened with a lever:
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http://www.poohbang.com/2011_11_27_archive.html
http://blog.artifactbags.com/machines-t ... ching-clam
The two examples I came across were both in America - they might be a commercial product rather than homemade. It looks like a 1970's modernist sculpture. The blocks at the top are not original (see links above).

I like this simpler design too (this used one went for £42 + £13 shipping on ebay - not cheap and they usually go for more):
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Rather than use construction timber, I'm using a slightly curved piece of green ash that I'd split and set aside for tool handles. I've hewn it into a couple of crude planks so far. Not sure if it will work out yet: the wood is a little curved although not enough to be useful. It actually curves in 2-planes and there are a couple of big knots at one end. Oh well, we'll see what we can do.
AshPlanksForLeatherClamDK.jpg
AshPlanksForLeatherClamDK.jpg (112.06 KiB) Viewed 9214 times

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Last edited by ToneWood on Fri Apr 18, 2014 3:24 pm, edited 4 times in total.
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Re: Saddlers Clam - leather holding system.

Postby ToneWood » Mon Mar 31, 2014 10:07 pm

Interesting video showing how a French company makes its stitching clams: http://www.fineleatherworking.com/blog/ ... wing-clam/

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I was surprised that a band saw is used to cut the curve (as it was for the large American clams above) rather than, say, using a natural curve and/or steam bending to maintain a continuous grain.

Searching google for images of "La Pince à Coudre" reveals numerous interesting design variations - check out the one with the plastic grip clamp :)
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Re: Saddlers Clam - leather holding system.

Postby ToneWood » Fri Apr 18, 2014 9:31 pm

I steam-bent the riven ash planks shown in an earlier post and shaped the ends using my trusty Mora 106 wood-carving knife. I have still not decided how to finish the clamp: open-by-default or clamped closed-by-default. While I ponder that, I decided to add a "leather hinge" at the bottom and pad the jaws.
LeatherClamPaddedJaws.jpg
LeatherClamPaddedJaws.jpg (45.5 KiB) Viewed 9134 times

The clam is already usable, by clamping it between my thighs in the normal manner. However, I will probably add a carriage bolt (or cord) to keep everything in place - either under light tension (and then use my thighs to clamp work tight) or under tighter clamping tension, in which case an opening lever (or brute force) might be required to insert work.
Last edited by ToneWood on Sat Apr 19, 2014 8:10 pm, edited 1 time in total.
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Re: Saddlers Clam - leather holding system.

Postby ToneWood » Sat Apr 19, 2014 4:47 pm

I've configured my clam to be "normally closed", for now.
Saddler's clam - normally closed.jpg
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