Why would someone do this:<
05-12-2014, 05:52 AM
#22
Super Member
Join Date: Oct 2013
Location: Centralia, WA, USA
Posts: 4,890
The wood does part around the needle, but not like leather or cloth. Even though it may feel rock hard and stiff to us, leather is soft and squishy compared to wood.
Think of the forces being applied like a nail being driven into wood. The same sort of things are happening. Just smaller. The needle pushes the wood fibers to the side but since they don't have the same give as cloth or leather, either the fibers get broken and crushed or if too close to the edge or end the wood will split. Splitting isn't as big a problem with plywood due to the alternating plys.
Think of the way a nail is driven into the board. It's not a continuous push like a sewing machine imparts. It's a sharp blow transferring the inertia of the hammer to the nail. How much steady force is required to push a nail through the plywood?
My guess is the plywood was sewn at full speed. Every time the needle hit the plywood was like a hammer hitting a nail.
The other issue is withdrawing the needle from the wood. Think of how much force is required to remove a nail once it's in. The small size of the needle and the fact that it's highly polished helps but still the presser bar and needle bar mechanisms were never designed for the forces being exerted in that direction either.
While you may not break the machine immediately, over time something will give.
Rodney
Think of the forces being applied like a nail being driven into wood. The same sort of things are happening. Just smaller. The needle pushes the wood fibers to the side but since they don't have the same give as cloth or leather, either the fibers get broken and crushed or if too close to the edge or end the wood will split. Splitting isn't as big a problem with plywood due to the alternating plys.
Think of the way a nail is driven into the board. It's not a continuous push like a sewing machine imparts. It's a sharp blow transferring the inertia of the hammer to the nail. How much steady force is required to push a nail through the plywood?
My guess is the plywood was sewn at full speed. Every time the needle hit the plywood was like a hammer hitting a nail.
The other issue is withdrawing the needle from the wood. Think of how much force is required to remove a nail once it's in. The small size of the needle and the fact that it's highly polished helps but still the presser bar and needle bar mechanisms were never designed for the forces being exerted in that direction either.
While you may not break the machine immediately, over time something will give.
Rodney
05-12-2014, 10:53 AM
#23
Super Member
Join Date: Feb 2012
Posts: 8,091
I have no hands on experience with industrial or shoe maker machines. But my LSMG has one of that type sitting on his show room floor and I've looked it over. It is one solid chunk of machinery.
However sewing plywood with it is the same as taking the family car and running on the drag strip Saturday night.
Do it once, you'll probably get away with it, but you've strained every part of the car beyond it's intended stress factors and you're gonna have a break down sooner than later.
Stupid move in my not so humble opinion, sewing that plywood.
Joe
However sewing plywood with it is the same as taking the family car and running on the drag strip Saturday night.
Do it once, you'll probably get away with it, but you've strained every part of the car beyond it's intended stress factors and you're gonna have a break down sooner than later.
Stupid move in my not so humble opinion, sewing that plywood.
Joe
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