ICD Lasoya Promaster - build thread

[tyronejk]

I'm now the proud owner of the town bicycle/Promaster:


I have a handful of small/medium/large projects in mind for this guy, mostly with the intent of modernizing it without throwing a bunch of expensive aftermarket parts at it.

1. Make a new rammer and modify the existing rammer housing to allow it to come out the back like a modern poppet. The ICDU rammer does this but those are unobtanium at this point.
2. Make a new bolt pin with a vertical groove for the bolt pin detent so it doesn't pull straight out (also like a modern poppet).
3. Make a new LPR end-cap to take a set screw for adjustment. I plan on finding a set screw that uses the same hex size as the HPR (3/16") to make adjustments easier.
4. Make new LPR and HPR valves and seats to take easily sourced orings as reg seals instead of these cup seals.
5. And finally new ASA and feedneck. These I'll just buy aftermarket parts for.
6. The stock trigger is mounted on just a simple floating pin and hole through the trigger, so I may modify this to take a bearing and lock the pivot in place.

[latches109]

Make a new rammer and modify the existing rammer housing to allow it to come out the back like a modern poppet. The ICDU rammer does this but those are unobtanium at this

Do you have an example photo of this?

[tyronejk]

Do you have an example photo of this?

This is the one and only picture I've found on the Internet of this (stock on top, ICDU on bottom):

[tyronejk]

Some quick CAD of the original rammer to estimate its mass:

And a new rammer sized to maximize the available volume in the housing somehow gets almost exactly the same mass as the original:

This new design loses the forward-stroke spring that's in the stock rammer assembly, but since the ICDU rammer doesn't use a spring, I think this should still work.

[Toestr]

The spring in the ram was to help prevent fsdo. Idk if it's necessary

[tyronejk]

New LPR cap/body designed to take the same 1/2" 3/8"-24 socket screw used for the HPR adjuster:

[tyronejk]

New bolt pin design:

[latches109]

This is what I was thinking of doing. I bought an extra ram housing from eBay recently test. Let’s make a larger Lazerous valve body too so we can run these with light rams.

[Trbo323]

I'm now the proud owner of the town bicycle/Promaster:

Me and now you are the only 2 MCB members to own that thing. I got it from a guy through PBF who I had been talking to for almost a year. I actually rebuilt it for him and sent it back and about 6 months later he was having issues and decided to trade me for a 98, something much simpler for him

Make a new LPR end-cap to take a set screw for adjustment. I plan on finding a set screw that uses the same hex size as the HPR (3/16") to make adjustments easier.

Why make a whole cap? Drill out the center of that one and use red lock tight to put a set screw in it. When my vanguard creed stripped out it's ram back cap because the previous owner had been using the wrong size wrench that's exactly what I did. That set screw is still in there today. It worked great

Sent from my motorola edge 5G UW (2021) using Tapatalk

[autococker04]

Hey now, I took it out of the box.

[Frmrspec]

if youre going with a lazarus valve then theres no real need to redesign/fabricate the rammer... toss a delrin hammer on there and call it a day, unless you want more dynamic shifting forces. However that ram could use a good polish (looking at those idiot marks on the shaft)

[tyronejk]

Me and now you are the only 2 MCB members to own that thing. I got it from a guy through PBF who I had been talking to for almost a year. I actually rebuilt it for him and sent it back and about 6 months later he was having issues and decided to trade me for a 98, something much simpler for him

Why make a whole cap? Drill out the center of that one and use red lock tight to put a set screw in it. When my vanguard creed stripped out it's ram back cap because the previous owner had been using the wrong size wrench that's exactly what I did. That set screw is still in there today. It worked great

Sent from my motorola edge 5G UW (2021) using Tapatalk

Ah ok, so only 3* owners, so not too bad!

This cap has a relatively thin back section (0.16") along with the slot (thinnest section is 0.063") means there would be relatively little thread engagement, especially if I use the same size set screw as the HPR adjuster.

if youre going with a lazarus valve then theres no real need to redesign/fabricate the rammer... toss a delrin hammer on there and call it a day, unless you want more dynamic shifting forces. However that ram could use a good polish (looking at those idiot marks on the shaft)

The idea of the new rammer isn't to reduce mass but make it removable from the back. I'm actually trying to maintain the same mass.

[latches109]

something like what Killshot_Kustoms was testing on his MT A4 angel.

[tyronejk]

Wow, nice! I was thinking a new back cap would be needed too, and I have a lathe but no mill so that wouldn't been challenging. But just the body I may be able to do.

[tyronejk]

I made a slight modification to the HPR by skimming a few thou off the top to get the macroline to sit inline with the gun body when screwed in completely:



And made that LPR cap mentioned previously and put a chunky knurl on it for better grip. I also added a vent hole for the LPR piston spring chamber, since this new cap doesn't have a vent hole through the center like the stock part does. Also, new clamping feedneck

[tyronejk]

something like what Killshot_Kustoms was testing on his MT A4 angel.

I took apart a Laz valve from another gun and got a drawing in CAD. It looks very doable on a manual lathe (after simplifying the original triangular port to a round hole). Now I just need to find time to machine this.

[devilzcall]

Threads so close to a shoulder are a bit of a pain and after doing a relief cut there won't be much thread left.
you could remove the outer wall of the forward facing o-ring groove and instead make it a part of your front spring-cap-thing

[tyronejk]

Yeah, good point. I revised this CAD after posting this and reduced the chamfer on the left and added a relief cut. The remaining thread is short but I think may be ok. The potential issue with using the spring-cap as an oring retainer is that its OD is smaller than this new valve body. Though I could add a washer to hold the oring too, since the left side is the pressurized side.

[tyronejk]

Updated CAD for Laz valve body with a little smoother flow path, large set screw divot, and thread relief added:

[tyronejk]

I found some old pictures of the ICDU rammer on PbN. It looks different than what I had modeled, so I may change my design to mirror this. But this requires boring out the entire original rammer housing, so I may keep my version. Either way, I'll upload those images here just to keep them online longer.