 |  | | | |  | |  |  | Two more GP diy conversions |  | |  |  | |
 Posted: Mon May 14, 2012 5:01 pm |
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| cyberfish2 |
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| Joined: 18 Apr 2010 |
| Posts: 33 |
| Location: N. Calif. |
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I have my Beeman RS2, and the new Tech Force 87 apart, awaiting Crosman Nitro Pistons. Must be popular parts; I ordered two a week ago, and Crosman is just shipping today. Interesting conversation with CS. "PARTS" can only be ordered by phone, and not tracked online. Complete items, ie airguns, can be tracked online. So even if I have a parts order #, and try to logon as "guest" , my order number will not be recognized. OK then.
Both these guns are Chinese made. The triggers are virtually identical, but not quite interchangeable because the TF87 uses 1mm larger pins to hold it in place.
The spring wire diameter is the same, .115, but the TF87 spring is 4.75" longer(removed), so I'm wondering if installing identical GP's in each will change the FPS?? The actual cylinder length is only about 1" longer in the TF87. It had more preload on the spring.
BTW, I'm sure some of you have already figured this out, but a metal lathe makes a great spring compressor. I put the outer cylinder in the 3 jaw chuck. ran the tailstock out about 3", and locked it in place with a slight load on the end cap. The 3 retainer pins tapped out easily, and I just backed off the tailstock to let the spring decompress.
More later as the mods progress.. |
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Tech Force Contender 87
.22 Gamo Whisper w/diy GP
.22 Crosman Titan GP
.22/.177 Beeman RS2
.177 Daisy 880
Several pistols and antique airguns. |
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| Posted: Mon May 14, 2012 5:42 pm |
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| Slavia |
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| Location: Waseca, Minnesota, USA |
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| Quote: |
| I'm sure some of you have already figured this out, but a metal lathe makes a great spring compressor. |
News to me, but I like it. One more reason to get a lathe. |
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 ¡Listo! ¡Apunte! ¡Fuego! |
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| Posted: Mon May 14, 2012 9:04 pm |
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| SMP |
| Silver Status Member |
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| Joined: 04 Feb 2011 |
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| Location: Just south of "Out There"- Land O Lakes Ontario |
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wow.....good info there 
whodathunk |
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Sean
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| Posted: Tue May 15, 2012 6:39 am |
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| radar |
| Silver Status Member |
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| Joined: 13 Nov 2011 |
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| Location: Des Moines, Iowa, USA |
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Another reason to tell my wife why I neeeeeed a metal lathe!  |
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It's never too late to have a happy childhood. |
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| Posted: Tue May 15, 2012 8:40 am |
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| SMP |
| Silver Status Member |
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| Joined: 04 Feb 2011 |
| Posts: 1183 |
| Location: Just south of "Out There"- Land O Lakes Ontario |
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Seems obvious to me  |
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Sean
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| Posted: Tue May 15, 2012 9:20 am |
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| Alstone |
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| Location: Linconshire, ENGLAND |
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Good idea cyberfish I'll give it a try next time I stripdown my B4-2.
Al |
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| Posted: Tue May 15, 2012 2:42 pm |
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| radar |
| Silver Status Member |
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| Location: Des Moines, Iowa, USA |
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| SMP wrote: |
| Seems obvious to me |
Of course! But women think backwards and upside down.
I'll be interested to see how the NP's affect the TF... |
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It's never too late to have a happy childhood. |
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| Posted: Wed May 16, 2012 11:05 pm |
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| cyberfish2 |
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| Joined: 18 Apr 2010 |
| Posts: 33 |
| Location: N. Calif. |
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| radar wrote: |
| I'll be interested to see how the NP's affect the TF... |
Me, too. I'm pretty sure the TF 99 is just a TF 87 converted to NP, so it looks doable. There only seems to be one size of the Crosman NP, at least, the part number is the same for the different models I was able to check. When I did the Gamo Whisper, I only had about .100" preload to hold it in place, so I could get enough stroke length to cock it. This may be a problem if anything is different on the next two. |
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Tech Force Contender 87
.22 Gamo Whisper w/diy GP
.22 Crosman Titan GP
.22/.177 Beeman RS2
.177 Daisy 880
Several pistols and antique airguns. |
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| Posted: Fri May 18, 2012 10:58 pm |
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| cyberfish2 |
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| Joined: 18 Apr 2010 |
| Posts: 33 |
| Location: N. Calif. |
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| cyberfish2 wrote: |
| radar wrote: |
| I'll be interested to see how the NP's affect the TF... |
Me, too. I'm pretty sure the TF 99 is just a TF 87 converted to NP, so it looks doable. There only seems to be one size of the Crosman NP, at least, the part number is the same for the different models I was able to check. When I did the Gamo Whisper, I only had about .100" preload to hold it in place, so I could get enough stroke length to cock it. This may be a problem if anything is different on the next two. |
The gas pistons came in today, and I decided to work on the Beeman RS2 first. I discovered if you're going to re-engineer something, it is best not to over think it. It makes your brain hurt.
I took a few pictures, and just tried not to alter anything until I was sure where I was going with my ideas. This time, I'm going to install the GP backwards, with the rod end toward the butt. The main body of the GP is just about the same diameter as the spring, and fits up inside the piston fairly well, tho I may have to put a thin sleeve at each end to keep it centered so it won't rattle. The end of the drive rod will only need a thick washer with a drill detent. Once again, the short preload should hold everything in place. The beauty of this, if it works, is I don't have to cut or modify any of the existing parts. |
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Tech Force Contender 87
.22 Gamo Whisper w/diy GP
.22 Crosman Titan GP
.22/.177 Beeman RS2
.177 Daisy 880
Several pistols and antique airguns. |
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| | | | | | | | | RS2 NP conversion | | | | | |
| Posted: Sat Mar 22, 2014 1:48 pm |
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| snakewolf |
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| Joined: 19 Mar 2014 |
| Posts: 1 |
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| So how did it work out. Have to cut length on rod or not. |
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