Pleats like in old leather postal bags

[bgillespie]

I'm trying to make a bag that is similar to one of the old leather USPS satchels.  I'd like the front pocket to have the pleat, but I can't figure out how to do it.  Every time it try to fold it into place it just doesn't look right.  The bottom of the piece is oversized by 2 inches and a bit on each side for 1 inch pleats.  I've noticed the top piece curves up, so maybe I need the top to have a slight downward curve to compensate for that.  Otherwise, the biggest thing is I can't figure out how to fold the things to look semi-symmetrical.  Maybe I'm overthinking it, though  Also, should I skive out some thickness in the pleat to help with folding, or is that a bad idea?

Any thoughts greatly appreciated!

[LiftPig]

I wish you were getting an answer to this.  I'm curious about it myself.

[buzzardbait]

Wet the leather, form your folds, let it dry and continue. You can gently tap them down into shape while they are wet.

[johnv474]

I have made several of those bags.  They are one of my favorite designs.

The front panel is wider at the bottom than the top.  From the centerline of your template for the front panel, along the bottom go about 2/3 of the way to the side and make a mark.  (for a 17inch bag, each pleat will be about 4.5 in hes from the centerline.  Draw a line straight up from this point to the top of the panel.  This will be the beginning of the pleat and you will bend it backwards. This becomes the edge you see after folding.

Then another mark 1/4" further (to accomodate for the bend), then another mark 1 inch further, then another mark 1/4" further. That will be the end of the pleat.  The 1/4" sections are where you will actually fold/crease/sharply bend... but in opposite directions.

Here is the key: draw a line from the end of the pleat mark to the SAME point at the top of the panel where you drew straight up from the beginning of your pleat.  In other words, you should have drawn a right triangle, 2-1/2" wide at the bottom, vertical side towards the center of the panel, diagonal toward the outside edges of the panel.

When you mark your stitches on the left pleat, the holes in each of the 1" sections are to line up.  put a special mark for the first and last holes in each 1 inch section so they do line up.  Go ahead and poke a small hole where the the first/last stitches are in each of the 1 inch sections.

To form folds, dampen leather throughout.  Fold along the beginning of the pleat (vertical)  over the edge of a table, board, etc., or just back on itself (grain side out).  Optional: press for a crisp crease with a bone folder, slicker, etc.  I fold mine over a ruler.

Then, unfold the vertical and go about folding halfway between the vertical and diagonal.  In other words, fold the 1/4" section. which is folded grain side to grain side, leaving the flesh side visible.  again, use a table edge plus a bone folder.

With the 1 inch sections folded and the holes aligned, stick a needle in the first hole and last hole in the 1 inch sections, for a total of four needles.  Clamp and let dry with needles in place.  If you dont have a clamp, theead the needle and loop it through those holes many times to hold them in place.

The ide is that the front panel, with those pleats, should end up the exact size as the back panel (the one that will rest against your hip). Typical might by 17 x 13 or so, or a similar proportion

When you go to stitch, if the leather is stiff, apply a little conditioner to the stitch line in the pleats so the holes will be easier to keep aligned.

This is a long description but a simple process.  Once you get it right once, you'll have it down.

Side note: the gussets in these are narrower (4" or so) at the top and wider (8") at the bottom.  The idea is that the bag will have a bit of a pot belly due to pleats, and increasing volume as you go lower.  The gusset stops tapering about 1/3 up from the bottom of the bag, and is then a steady 8" or whatever along the entire bottom.  It's easier to make the gusset symmetrical, tapering front and back. Now that I think of it, the taper of the gusset and the taper of the pleated panel before folding might line up almost perfectly, to minimize waste.

 

Hope this helps!

Edited May 2, 2020 by johnv474

[johnv474]

Here is a link to a thread about this. Look for the photos in that thread for a downloadable schematic posted by Possumbreath.  You can see the triangles I referred to.  here you go.

Edited May 2, 2020 by johnv474

[bgillespie]

Buzzardbait and johnv474 thank you both so much!  This is a huge help.  I have been overthinking this one for a while, it seems.  Johnv474, thanks for all the detail.  It definitely helps clarify the process.  Time to get to work and see how it goes!

[Frodo]

[bgillespie]

Well, I gave it a shot again. Got things to look more symmetrical, but the top still bows up a lot.  The piece is oversize so i can always trim.  The bottom is fairly on the mark, though.

[johnv474]

I think they only make the fold/crease a little over halfway up the panel, then kind of let it ease back to unpleated at the top.

You are definitely moving in the right direction. 

On 5/2/2020 at 1:37 PM, Frodo said:

Frodo, this illustrates it very well.  Thanks

[bgillespie]

Thanks for the clarification.  I'll try it again.  It gets a little easier each time.  I'll wet it again  and see if I can ease the top out a little.  I'll get there eventually!