Once again time has gotten away from me. We are in the shop 7 days a week working on the projects and stuff actually gets accomplished. The updates this week will show the good and the bad that we have had in the last couple of weeks.
First will be the really bad and that is stamping the Japanese type 99 magazine. Our biggest mistake was trying to accomplish to much with a single die. It did not work. Instead of pressing the sheet metal it sheared it instead.
So this lead to redesigning the dies and the process that we are going to use. We have gone to a multiply step process. The first set of dies will just stamp the groves, the second set will bend the sides and the third will set the angle and do the base plate edge. this is a picture of the new first set of dies.
I hope to be back at the press with the new dies this week.
Now a completed project that was fun and interesting. We had a UZi that was brought in for repair. It is a dealer sample converted weapon that would just not work. The first thing we needed to do was machine out the bolt to fit properly.
However with this type of boring bar the chatter and movement was just to great. We changed to a stiffer bar and all was good.
With the bolt problem corrected we still had problems. It would fire one time and then run away. The problem was the excessive movement of the pistol grip. The original grip is set for an 8mm pin and the converted weapon uses a 9mm pin. Once we open the hole in the grip and installed a new proper size pin everything worked like a dream.
We are also working on the VG1-5. A great deal of work was accomplished on the upper receiver. The first 5 which are the test rifles are just about completed. we set up the fixture to all us to cut the majority of the upper receiver.
This allowed us to machine the bottom hole and the slot for the guide slot.
All the guide slots have already been machined.
This how they fit on the receiver.
The cocking handle holes have been drilled.
The rear sight dove tail slots have been cut.
In addition to this we also finished the FG-42 butt plate stamping die and started stamping them. That will be the next post and I have to get back into the shop and get to work.
Good work, Ian & thanx for the updates…after spending five or so years in the Sikorsky Sheet Metal Shop as a paper-pusher (Production Control) I finally realized (too late) what I wished I learned – a trade in machining/metalworking…I’m always impressed how one can take a block of steel or aluminum and uncover the hidden useful part that is locked inside…As Michaelangelo is rumored to have said…sculpting is easy…you just remove the pieces that don’t look like the ‘final product’….congratulations.
CB in FL
Thanks, Chris – but the work being shown here is all Chuck’s.
Think you will need selective lubrication to get the front of the magazine to form, rather than shear, even with the multiple step methodology. NLGI Grade 2 grease with moly makes a good impromptu lubricant if the shearing reoccurs or you encounter wrinkling.
Paint a thin layer on the outside only from the front bend line to the edge of the blank. This will prevent the sheet from sticking to the outer die and promote metal flow in this complex area. We used to describe this kind of forming operation in engine bearing shells as ‘forcing steel to commit an unnatural act’! It is a very difficult stamping operation to undertake without cracks or wrinkles. You will also encounter rapid outside die wear in this area without lubrication.
Wax dissolved in xylene makes a more serious lube, and is still much cheaper than commercial formulations. Oils are too thin and don’t provide adequate protection against adhesive wear.
We have tried a variety of lubricants But I am willing to try anything that might help. Thanks
Gardolube RS 5770. In the past, I’ve had good luck with it for heavy high-contact forming. Reduced/eliminated wear on the dies, and in my case kept the surface from being scarred by the die and almost eliminated metal transfer onto the die. I used it in an extreme forming application as a replacement for zinc phosphate and soap. It had no effect on secondary operations such as plating or painting. Greases kept wiping/shearing in my case. The more of this fluid we had in the affected areas, the better it worked. If it’s applied too thin, it can shear or wipe away as well. It worked extraordinarily well when applied to manganese phosphated parts.
Stuff smells terrible, costs a little bit, but a 5 gallon bucket should last you a good long time for this kind of work.