7 Attachment(s)
Assembly Fixture For Cannon or other Models
It all started a long time ago while reading posts from this forum. I found this Cannon that Marv Klotz made.
Marv's is a firing model but I am just making mine for display. https://www.homemadetools.net/forum/...deck-gun-46438
I knew I wanted to build one but at the time (probably 5 or 6 years ago) I knew it was above my pay grade.
I figured that now was the time since I had my lathe and mill and a little knowledge (much from this forum) for this build.
The copy I am making will recoil, breech will open and is of the interrupted thread type. Still working on parts for the base.
First I had to find the magazine where the original plans were posted. March and April of 1945 Model Craftsman magazine.
Found the entire year for 1945 on the bay and snapped them up.
So I started making parts..The barrel first of course and then moving on down from there. So I have enough of it finished to do a bit
of assembly but no easy way to hold the parts in alignment. I had several work plates in the shop so I thought one of them would make a
good base and was just right for what I wanted to do. The
Here are the pictures of the fixture in use. It is the best way I could think of to hold 6 parts together to test for fit and function.
The end result of the fixture and it's capabilities are just what I was looking for. Basically two angle plates with two modified spindles at the top.
The two pins are made from 1/2-20 all-thread. One end of each is bored to match the trunnion pins. (other end left undrilled for future use).
Two brass knobs with fine knurls..(I can't pass up a chance to knurl!)
10-32 allen cap screws attach the vertical post to each base and a .260 slot in the base allows for coarse adjustment.
5/8" x 1 1/4" aluminum bar stock for bases and posts. Extra holes spotted for future use and the layout lines are left in place.
I made it larger than needed for future modification.
Posts are 4 7/8" long and the bases are 1 1/4" x 2" long.
Here's the pics:
3 Attachment(s)
Alignment Fixture Proof of Concept
The fixture worked perfectly. I used solder paste after cleaning all parts with Acetone. The parts were assembled with a light layer of paste and I added two fiber washers to each trunion pin to reduce heat loss from the fixture. Only needed about 15 or 20 seconds on each side (from the inside of the housing) with my propane torch.
First picture is the assembly as it was soldered.
Picture 2 is the part from the bottom and you can see just a tiny bit of over solder. (It is on the bottom and I am leaving it!)
Picture 3 shows the fixture ready to release the assembly. It had just enough clearance to exit the fixture without taking the fixture apart.
The fixture will be used to install more parts when they are ready.
Cheers, JR
