gehko NZ: This is something that interests me, I'm a textile mechanic over here and very old machines (bar tackers included) are pretty common, you can't give them away half the time, I could see how a new programmable bar tacker could give a slightly different stitch, but mechanical ones all work pretty much the same as each other, once someone designs a machine, everyone else just copy's it, the basic design of many types of machines haven't changed in quite some time, theres a place (a hat place) we have done work for that I found out makes or used to make PASGT helmet covers, I got a blue UN cover off the net with their label in it, and their still using machines that would have been around during the 40's, because no ones making anything new to replace them.
From my point of view, IMO the stitch itself wouldn't be hard to replicate if you knew where to look, the thread used might give more clues.
Mr-X: Prior to leaving to go to university, I worked in the textile manufacturing industry for over 10 years. I have used many a bar tacker. I can tell you that its not the age of the machine, its the stitch that it is set up to perform that is important here.
Older manual bar tack machines such as the very common and very good Singer 269W or etc, will more than likely be set up to stitch a 42 stitch 5/8in long 1/8in wide end stop pattern bar tack. This standard bar tack is a little too spaced out for the very concentrated stitch (more like 3/4in long 52 stitch) that is on the M-1 helmet chin straps. Manual machines are not readily changeable as to stitch pattern. They use a geared plate to make the stitch and that needs to be replaced to change the stitch. Different sized plates are a rare spare part. My sewing machine mechanic laughed when I asked him if he could change the one at work. Later 269's had variable length and width but not number of stitches.
Modern programmable machines can give you an end or center stop bar tack or flag stitch at the drop of a hat. However the one my previous employer bought cost $5000. Which is a lot of money to spend just to fake up some M-1s. It never really produced a bar tack as good as the original anyway.
A 42 stitch bar tack with the correct color and thickness cotton thread will look the part but it will not stand up to an expect look. With the amount of rebuilt M-1s being sold off as original the chin strap bar tacks are something that we will all need to study.
BTW I am unable to find out which particular type of bar tack machine was used by McCord during the war to make M-1. But they must have been very reliable. There were 22 Million M-1s made during the war. Each had 3 bar tacks each. Thats 66 Million bar tacks in 4 years. Thats an average of 48,000 bar tacks a day.
Mr-X Second Post: Here is a drawing of a standard 42 stitch bar tack.[Check Post #9 at this link to see drawing: http://www.usmilitar...showtopic=15340 9
(FORUM EDITORS' NOTE: we have edited this post to include the bartack information from the other thread)
If you count the stitches on the top or the bottom you will find that it numbers 15.
If you count the ones along the top or bottom of the bar tack on you M-1 chin strap you will find that it number more like 20.
20 top and 20 bottom with 10 inside makes a 52 stitch bar tack.
They are hard to count as they are more tightly packed in than the 42 stitch bar tack.
I hope that this helps to understand what I am on about.
I also hope that it is not too technical.
Edited by Forum Support, 12 February 2008 - 07:44 AM.