How thick is your ABS plastic (the blades)
I'm using 1/8"(.125") ABS plastic because I have a whole sheet of this stuff.
Going off of this reference pic, I drew up my blades.
I made two templates using manila folder. One was made to be like the pic and the other is shorter and straight to facilitate the movement without being so damn long.
I made a plastic template so that I could have a more permanent template. Not that that matters, the folder paper lasts a while if it's not abused.
I cut my 15" X 2" stripes and glued them into pairs to double up the thickness to get to 1/4". Then taped them all together and traced out the blades.
The main tube and blades are made from 1/8" ABS. The blades are two pieces laminated together to eliminate the hair cell from showing.
Most of this wasn't really measured, it was cut to fit.
The blade assembly is 1-5/8"W x 2"H
The I.D. of the launch tube is 1-7/8"W and 2-1/8"H
The tubes length is now 11.5"
The blade length is just shy of 15"
So the overall length when retracted it 15"
Extended it's 23.25"
-So it has a 8.25" stroke-
The top cover was rounded over for looks and the blade block was rounded to match it. The U shape cutout was so that it could go another 1/4" further out and I add a second catch on the front because of this.
Because of the way I folded the plastic it radiased a little more than I inteded and therefore I had to have more space either on top or on the sides. I left it on the sides. This allows for free unbound movement. I added small things I'm calling guide spacers that take up the wobble when fully extended. They aren't need when retracted because of the rubber band tension.
The two issues I've been trying to minimize are the binding on the rubberband and the rubberband herniating forward. With loose tolerances the binding is gone and I have the rubberband tethered to the middle near the screw to minimize the herniation.
Does that awnser your questions on this, or where you looking for screw sizes and stuff?
you know what? I was seeing it wrong, I'm sorry, I wonder if a little u-bolt of some sort on the stop bolt would work? Well I'm heading over to Lowe's tomorrow and see what I can find, thank you very much for this post because I was racking my brain on how to make retracible blades without making it too difficultThanks.
If I'm understanding you right about the two bolts, I don't think so. Anything else in the tube may end up as a snag hazard for the blades.
What I've found out in the practical setting is that the rubber band isn't really necessary and even if it pops out, it’s not that big of a deal. The blades slide perfectly with out the rubber band and I think I may just run without it now and let gravity do the work.
The two problems I’ve had while in costume have been the rubber band moving and coming off the blade block and the pull string wearing through on the front lock. The rubber band part was fixable easily enough during a break. The front string breaking was annoying but it meant that the blades were locked out(which was OK). The string rubbed through at the front screw. I think a small tube will help eliminate that.