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Resin Sterling end cap, D-ring lug and possibly more?

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After multiple requests and a few stops and starts, I've finally made some progress on this...

 

At first glance, molding a Sterling end cap doesn't seem too difficult.

However, based on the modifications required for resin builds, I wanted to "make a better end cap".

I thought I would simply disassemble the cap with an acetylene torch and mold the parts, but that's where the problems started.

 

The Sterling end cap and lug are actually ONE SOLID PIECE of machined steel.

The lug is machined into the rear of the cap.

It certainly LOOKS like a separate piece, but it's not.

I nearly destroyed a perfect cap trying to remove the lug.

While heating the cap (bright cherry red), I made an ASTONISHING discovery (or at least I thought so)...

 

I always thought the D-ring was formed from a solid steel rod - it's NOT.

My D-ring "fell apart" while heating.  It is formed from TWO u-shaped pieces with alignment pins.

Best I can tell, each piece has a small amount of silver solder applied, then they are inserted from either side and heated.

When I made this discovery, the end cap was so hot, it more or less melted portions of the D-ring.

I took measurements and made a CAD drawing of what was left.

 

THIS is what the Sterling D-ring pieces look like, before installation:

Rhino%20D-Ring_zpsiwbyvvl8.jpg

 

With that discovery and the D-ring out of the way, I decided to cut off the lug and machine the rear of the cap flat.

Then, I machined a shallow recess into the rear of the cap.

 

E8E9659C-2F93-4121-BC08-8AC6C6A72C71_zps

 

I used the cut off piece of the lug to fabricate a new lug.

For this, I used a wooden disc and epoxy sculpting putty to form the rough shape.

Realizing most builders use a one piece D-ring, I cut an open slot in the rear of the new lug.

After rough shaping, I used Tamiya putty to smooth out the part and finesse the details.

 

3753E05B-2A74-4BAF-85BE-21AEA0DEAF7B_zps

 

I used the D-ring from Tino's excellent Completion Set to size the rear slot.

 

C3D1A2FB-EEDD-423A-895F-6A23E2F307DE_zps

 

After a little filler primer, I can see the need for a few touch-ups.

 

4961F0FA-7F05-4882-8DD7-2F4E226D82A5_zps

 

Here's the end cap from my Sterling replica next to the modified pieces.  Crazy close, no?

 

AD8305D1-F907-496F-9DE5-4CC79EFD9523_zps

 

While I was playing around in CAD drawing the D-ring pieces, I did drawings of a couple more things I've always wanted to make from metal...

These pieces could be laser cut from aluminum or steel, then rolled or folded.

I'm still working on how to press the knurling into the metal - any ideas?

 

The notch ring and the front sight guard...

 

Notch%20Ring_zpsu4kmnh5c.jpg

 

Rhino%20Front%20Sight_zps2wk085t0.jpg

 

From here, I'll further finesse the parts, then make silicone molds for the end cap and lug.

 

Stay tuned for more!

 

Aaron :)

Edited by usaeatt2
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Genius! :th_AnimatedBravoSmiley: I have been waiting to see what you had in store for some time now and so happy to see these new developments.  I had wondered during my build how they managed to get those rings on the end cap and did notice the rings on some Sterlings had some centered lines as if they were two parts but never felt certain about it. Great you solved the mystery!  Is it possible to have similar d rings fabricated to snap together like the real ones? Or a plastic version? It would make it easier to leave the end cap as a solid piece as it actually is and then all you need to do is snap the ring parts together and cover up the outer seam.   I realize you are doing the end cap in two parts for people with solid d rings and end caps parts pre separated but I think adopting the 2 piece d ring & a solid one piece end cap if possible would be the easiest and truest to Sterling construction. Maybe a another upgrade kit from Aaron's prop garage? 

 

The notch ring looks awesome and will be great if it works.  Just wondering, is it possible to have a solid ring and have the notches cut by a machine shop? Probably expensive but would be a simple 1,2,3 install. I found that when I rolled aluminium sheeting over a tube form , the very ends never sat flush to the form. slight warping.  this part does get covered up so probably not much of a concern I guess.

 

The front sight guard will be neat if it can be done. I know nothing about the knurling process but saw one of those discovery channel shows once stamping knurling patterns into tool handles and other things. That would require some sort of reverse metal stamp you would need to hammer into a softer metal.  I was thinking if there were flat metal sheets slightly thicker than the normal guard with the entire surface stamped in the knurling pattern , then it would be easier to sand/file/polish down the parts on each side without the pattern.

 

Exciting news Aaron and can't wait to see more on these parts. Always ready to order more of these amazing upgrades regardless how much more Star Wars debt I am in!  :jc_doublethumbup:  :jc_doublethumbup:  :jc_doublethumbup:  :jc_doublethumbup:  :jc_doublethumbup:

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The end cap on my kit has always been a big bleh part for me.

 

I've thought about molding the end cap as a single piece and I proved it's possible with the F11 end cap I just did. The problem is the Dring as you said.

 

When I get the metal parts kit form you and cut off the dring I also noticed the construction and thought this would be the solution but replicating this isn't cost effective.

 

So then I considered doing exactly what you did be forming a recess and reshaping the holder to fit in it.

 

Well done!

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Is it possible to have similar d rings fabricated to snap together like the real ones? Or a plastic version? It would make it easier to leave the end cap as a solid piece as it actually is and then all you need to do is snap the ring parts together and cover up the outer seam.   I realize you are doing the end cap in two parts for people with solid d rings and end caps parts pre separated but I think adopting the 2 piece d ring & a solid one piece end cap if possible would be the easiest and truest to Sterling construction. Maybe a another upgrade kit from Aaron's prop garage? 

 

The notch ring looks awesome and will be great if it works.  Just wondering, is it possible to have a solid ring and have the notches cut by a machine shop? Probably expensive but would be a simple 1,2,3 install. I found that when I rolled aluminium sheeting over a tube form , the very ends never sat flush to the form. slight warping.  this part does get covered up so probably not much of a concern I guess.

 

The front sight guard will be neat if it can be done. I know nothing about the knurling process but saw one of those discovery channel shows once stamping knurling patterns into tool handles and other things. That would require some sort of reverse metal stamp you would need to hammer into a softer metal.  I was thinking if there were flat metal sheets slightly thicker than the normal guard with the entire surface stamped in the knurling pattern , then it would be easier to sand/file/polish down the parts on each side without the pattern.

 

Hmmm...  You have me thinking, Brian.  Maybe it would be better to cast the end cap as one piece and create a 2 piece D-ring instead.

Casting the 2 pieces in resin would be easy, but fragile.

Fabricating the 2 pieces from metal would be more difficult, but strong.  I'll have to think about this.

 

You are correct about rolling a flat sheet.  Rolling it by hand would be difficult, especially near the ends.

Rolling it on a slip roll would require the slip roll to be disassembled to remove each finished part.

BUT, if many rings were CNC'd into a tube, then the rings could be pared off on a lathe.

Or maybe a rotary laser cutter - I wonder if such a thing exists?

 

The knurling on the sight guard is almost exactly 3/4" from front to rear.

The pattern on the part is already reversed, so normal knurling wheels would work, if I can find them 3/4" wide.

The problem with the front sight guard is the thickness.

I was thinking 1/16" thick so it could be formed by hand.

The actual part is just over 1.5 times as thick and would be impossible to form by hand.

Which makes me think I could form simple dies and press them into shape on a hydraulic press.

 

All of this is possible, but it comes down to cost.

Only making a few causes the cost to be too high.

Sterling was producing hundreds of thousands of these.

Either way, reverse engineering is fun!

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AD8305D1-F907-496F-9DE5-4CC79EFD9523_zps

 

Really a perfect copy of the original end cap. The slightly bigger seamline will surely reduce after some layers of paint.

This photo also shows, the ring is a nice match.

Any idea why the bottom of both end caps are different? (meaning the area below the ring)

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Any idea why the bottom of both end caps are different? (meaning the area below the ring)

 

The end caps are the same.

The recess I machined is slightly too high, so the ring doesn't fall in the same location.

I machined the recess based on the location of a center countersink on the inside of the cap.

Easy to be off a little when moving from inside to outside.

If I did it again, I would do things differently based on what I learned the first time...

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My response is, I WILL TAKE IT! Your muzzle kits are over the top so yes please, pretty please, what ever please you would like. Lol when will they be ready.

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Great stuff Aaron!

 

I think it was this distinct difference in profiles that Tino may be talking about. First thing that jumped out at me too. Or is it just the colouring/shadows making it appear different?

 

AD8305D1-F907-496F-9DE5-4CC79EFD9523_zps

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Great stuff Aaron!

 

I think it was this distinct difference in profiles that Tino may be talking about. First thing that jumped out at me too. Or is it just the colouring/shadows making it appear different?

 

AD8305D1-F907-496F-9DE5-4CC79EFD9523_zps

 

WHOA!  Thanks for the highlighting, Ian.  I didn't notice that before, but I see it now!  I'm going to take an educated guess here...

I'd be willing to bet the highlighted differences are due to the fact that my Sterling replica is based on parts made at the government owned Fazakerley facility.

We've already seen other differences such as the infamous "slotted versus solid extractor" which created a small ruckus here several months ago.

Little differences like this make my replica even more valuable to me.

 

Take a look at this link for more background history:

http://sterlingl2a3.com/markings-and-spares/

There's a lot of cool stuff on that website if you click around on the tabs at the top of the page.

 

Sterling apparently beefed up or changed certain areas of the gun over the years and this could be another one of those subtle changes.

OR, it could just be a difference between the caps being manufactured at the Sterling and Fazakerley factories.

Difficult to say for sure, but leave it to you guys to notice such things!  I learned something today!

 

 

Oh and I still think you should cast a bolt

 

Kevin, you're making me laugh!!!

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WHOA! Thanks for the highlighting, Ian. I didn't notice that before, but I see it now! I'm going to take an educated guess here...

I'd be willing to bet the highlighted differences are due to the fact that my Sterling replica is based on parts made at the government owned Fazakerley facility.

We've already seen other differences such as the infamous "slotted versus solid extractor" which created a small ruckus here several months ago.

Little differences like this make my replica even more valuable to me.

 

Take a look at this link for more background history:

http://sterlingl2a3.com/markings-and-spares/

There's a lot of cool stuff on that website if you click around on the tabs at the top of the page.

 

Sterling apparently beefed up or changed certain areas of the gun over the years and this could be another one of those subtle changes.

OR, it could just be a difference between the caps being manufactured at the Sterling and Fazakerley factories.

Difficult to say for sure, but leave it to you guys to notice such things! I learned something today!

 

 

 

 

Kevin, you're making me laugh!!!

that's what I'm here for

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not sure if it helps, ruins plans, but here are some different angles :)

 

Both fit fine btw... Love your work usaeatt2 ;)

 

Without reading the previous links provided in this thread (excited again)

i know that the left is a <66ísh model, and the right one a >later model....

fqNs9Gw.jpg

 

XIJmXYk.jpg

 

SLt8u5H.jpg

 

orJbBYX.jpg

Edited by Tr00per
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THAT is exactly the difference I was talking about :) Thanks for the perfect pictures...

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Thanks for the professional pictures, Tr00per!  End caps never looked so good!

 

These (based on the later cap) coming to a sales thread SOON!

 

0e679e61-6c93-46f7-8855-569ff167e76f_zps

Edited by usaeatt2
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