Chassis Build

The receiver stock is done. I had a few anomalies with some of the tool paths where the cutter skipped over some of the details during the 3D passes. It's kind of strange where most finished dimensions are within a few thou which I think is good considering there were tool paths on 5 of six sides but there are a few that were 10 to 20 thou off, all on the 3D tool paths. Part of the path would be perfect and another part would be slightly off. I have some backlash in the system I need to take care of and it really shows in some of the blend lines.

I also discovered the 3D CAD model of the receiver I got from a friend wasn't modeled correctly. The important dimensions were there but the taper at the rear of the receiver is way off and the slot for the bolt handle is not deep enough. I'm going to try and recut the taper. Hopefully it comes out okay. I'm still trying to figure out how to use extra long end mills without leaving chatter marks.

Stock05.png Stock06.png Stock07.png
 
I normally am not intrigued by CNC machining. It does not do much for me, but this project is amazing and well documented. The videos are awesome. Thank you for taking the time to post this.

"Billy G"
 
I'm not into guns but that is a beautiful piece of machining.

Tom S.
 
I was able to recut the back taper to more closely match the receiver and recut the pocket for the bolt handle so now the receiver stock is done.

Next is the part that mounts the barrel guard to the stock.


Solidworks Model
BarrelGuardMount06.png

Rear side tool paths
BarrelGuardMount07.png

2" x 3" x 2.5" block bored, turned and here getting the taper cut.
BarrelGuardMount01.png

Bolted to the fixture ready to machine. Normally I would hold a part like this in a soft jaw but it needs to be milled on both ends so the same fixture can do both sides. That's a 1/2-13 bolt holding it in place.
BarrelGuardMount02.png


Drilling and milling completed. I normally model the part and the fixtures and then do the CAM from that assembly. I can then run stock simulation to look for clearance or tool path issues. Because I did the fixtures on the lathe as they were simple I did not bother to model it. Well that bit me. I failed to adjust the default clearance height for one of the 3D contouring operations and when it finished it went to the safe Z that was too low and then to the starting position for the next tool which was across the part. That cost me a 1/4" carbide ball end mill when it tried to rapid through the steel bolt head at 50 ipm. Ugh!
BarrelGuardMount03.png

Ready for the front side.
BarrelGuardMount04.png

With all the roughing work I have done this week the cutting fines are wreaking havoc with the coolant pump check valve and I keep loosing prime on the pump. I need to sort that out before continuing.
 
Very nice work! What are you using for CAM?


Stan
Sent from my iPhone using Tapatalk
 
Thanks! I wondered if that's what it was. I'm just getting my feet wet in Solidworks (was using Fusion but had to have sheet metal, so bought SW).
Love the project, gives me some ideas!


Stan
Sent from my iPhone using Tapatalk
 
How did you get the inlet for the receiver/redo the rear tang?
 
You must log in or register to reply here.
Back
Top