We were stymied earlier this week by not being able to get to tapping some holes in our 12lb'er, so today was all about the thread-cutting ... oh, and some other stuff! Hit Back after viewing an image.
Here's the secret ingredient - Tap Magic! And unless our noses are deceiving us, it now comes in a pleasant citrus scent?! Any which way, it was time to get to tapping.
First up are the side rails, which receive a 10-24 thread for the spacer bolts. We were being extremely careful, as it's been a few years, but we have bad memories of breaking taps in awkward places, and we couldn't afford to mess up these pieces.
Carefully does it, and after not too long we have one side done. Looking good!
Plenty more pronation and supination of the wrist leads to both sides being complete, including the front dead axles, without breaking a tap - bonus!
The next step is to drill and counter-sink the holes for the front wall. Due to having slots for the weapon belt, the hole patterns are dis-similar, but things came out fairly well.
Ah ... end-drilling polycarbonate ... brings back all sorts of memories from the Build Space at the ISP, constructing Bad Grammar and Sloppy Spelling ... good times.
After some more careful tapping, we can now assemble the front wall - looking good!
In the absence of a mill to call our very own, this is how we cut the rear wall and weapon motor mount: by taking a jigsaw to a length of 2" x 1/4" 6061, and then sanding down the ends. Makes us remember a commercial from a number of years ago that proclaimed "Nothing in the world chills down as fast as Alumin[i]um" ... of course the corrolary to that is "nothing in the world warms up as fast as aluminium" ... those pieces got pretty warm while being sanded down to length.
This picture was taken after the cursing and profanity had finally subsided. We tried end-drilling the inner rails on the drill press, but the curved end, combined with the 8" length led to slightly too much wobble, and we broke a 7/64" drill bit in one of the holes. Drat! After that we took the slower route of a hand-drill and the bench vise. Luckily, that was successfully accomplished.
The finished back plate, with additional holes for the drive motor and gearbox mounts. We're still undecided on hole placement for the top and bottom dust covers, so we'll come back to those at the end.
Test-fitting the inner frame. Worrily it's not totally square, having a bit of an upwards warp in the back corner. We're going to put that down to not using the right bolts on the back, for now, and hope it doesn't come back to bite us!
A quick shot with the motor and gearbox mounts sitting in place. It occurred to us that if we wanted to we could bolt some thin polycarb across the front of them as another surface to mount ESCs, etc., from, but we'll hold that idea in reserve for now.
With the dead axle for the drum bolted into place, the frame-warp doesn't get any worse, nor any better, so that should be okay ... right?
Just testing ... the outer rails fit just fine, and the drive axle holes seem to line up okay, so that's good.
Throwing a few of the internals in there for good measure. We do still need to make a battery retainer, but otherwise most of the rest of the parts are cut at this point. Still plenty of tapping to be done though!
For example, drilling and tapping the mounting holes for the Whyachi MS05 power switch. We don't seem to have any bolts that are the right size, though, so we'll have to go pick some up next week.
We'll wrap up for today by stinking up the Build Space - a coat of Team Radicus purple, followed by clear top coat, for the outer rails. Time to go clean up for dinner - not a bad day's work!