one other tip when you tighten the locknut on the foot pressure spring don't make it to tight it can jamb that rod from going up and down so just light pressure on that nut.
Welcome from Massachusetts this is how it all starts next thing you know tour buying 5,000.00 dollar sewing machines and all the hand tools it does not end you'll see but good luck talk soon.
Well there you go then permanently blinding someone with oven cleaner or something of that sort would be the best deterrent I agree I wonder why we go with the temporary blindness stuff that has all that infrared tracking dye that don't wash off and all that good stuff in it you can use it for an attacking dog's to. Are those attackers that were charged sent to a prison for the blind . LOL
Frodo I made one for my brother looks similar but mine was filled with 10 dollars in quarters with a flap that you would pass through your belt fold it back down and snap to the money end that flap was the handle very effective but if questioned by police it's just a change purse.
Make the insert lots of planning how it will work and all that but from what i see a man of your talent should have little problem the planning of the insert can be a lot of fun one thing go to a thrift shop get some bags a deconstruct it helps to see what others do good luck with it Dwight.
I would cut two circles of 3/4" plywood about 8" then wrap the leather around to create a cylinder nailing only one end to the plywood you can let the long seam lap over and glue with barge cement then go outside dig a hole about 3' deep go back in the house get the cat place him/her in the cyl then place the other 3/4 " plywood end in the end and nail around the edge take the thing outside and put in the hole cover with the dirt then a stone around8" on top thats it nice use of the leather most of all have fun you can hit the cat with the shovel first if you wand but it's not needed .
" If you are distressed by anything external, the pain is not due to the thing itself but to your own estimate of it; and this you have the power to revoke at any moment "
----Marcus Aurelius
So don't compete with them do your custom thing and market to that demographic make your product better or different enough that the extra price doesn't matter and that is two ways to solve your problem it's a lot of work but it can be done. "Obstacles are what you see when you take your eyes off of the goal"
My two brother in laws worked at the same prison here in Mass one of them got my farther a prisoner made leather wallet I got that wallet at some point and still have it. It's a very nice piece of work , that's from about 40 years ago.