Friday, November 30, 2012

Checkering the Crosman 112 Grips

Coming back to the rosewood and maple grips for the Crosman 112















They were built rather plainly with the intent of checkering them at a future date.  I've been sitting on a basic set of Dembart checkering tools.  Got the 18 lines per inch kit.





















Read the directions a couple times and decided to give it a go.  These grips were pretty dead simple to make so if I ruin them beyond all hope, I haven't lost much.    Marked a few pencil lines on the left grip that represent a 3:1 ratio.


















Then scratched the lines into the wood with a flexible steel rule and a sharp scribe.

















I have no idea what to expect.  Deepened the lines with a single line cutter.


















Followed up with a double line cutter.  Used each existing line as a guide to cut the next.































Now the other direction to create the diamonds.  The cutter needs frequent cleaning of sawdust or it clogs and runs off track.















It doesn't look like much at first, then the diamonds start to form.































Got to about here and didn't like it.  Decided to fill in the pattern over the rest of the grip.


















I like the full coverage better.  Brushed a coat of Arrow Wood Finish into the grips with a tooth brush.




























































A few run overs and some slight tracking issues here and there.  Overall, much better than they were.  Guess I'm OK with them as a first effort.  They're sharp to the touch and feel great in the hand.


More soon.

Monday, November 26, 2012

Daisy 790 Loading Trough Repair

Here's some of the Daisy 790 parts gun I purchased almost two-and-a-half years ago.  It was in a cardboard box and priced to low to pass on.  At the time, I bought it so I'd have spares for a Smith & Wesson 78G purchased ten minutes earlier.  Keep in mind that the S&W 78G and 79G (.22 and .177 calibers respectively) designs were sold to Daisy in the very early 1980's.  Daisy renamed them 780 and 790.  Daisy just changed the "G" to a "0".  For the most part, the parts are all interchangeable, so simpletons that we are, we write about the guns as though they are identical.  If you're new to this blog and need repair information on the Daisy guns, check the blog index for "Smith and Wesson 78G" as Nick and I have cataloged the bulk of the work there.












After getting the Daisy home and starting assembly, I realized it was missing the trigger.  OK.  It's a parts gun.  Set the box aside and shot the S&W 78G.


















Eventually, I took the time to work the phone and the internet and tracked down a trigger.  The I hit the next roadblock--and the likely reason the gun ended up in the box in the first place.


















The real problem:  The loading trough isn't aligned with the breech.  It's noticeably offset to the right.


















It's also far too wide and deep for a .177 cal pellet.  Actually, it's too large for even a .22 cal.   And why is it in the white when the rest of the gun is painted?   Did Daisy have an insert for the trough for the two different calibers?  And why wasn't it centered with the bore?  Very odd.


















Thought about plugging the hole and re-drilling.  Didn't think that was a very good idea.




















 





Here's a better pic of how much it's off.  The loading bolt gets pushed to the right and then drags and wedges in the breech before it locks closed.


















I finally just decided to file out the left side of the trough by hand and make a sleeve.


















In this case, it's not important that the hole in the receiver be perfectly round.  It's important that it's centered for the barrel.


















Cut down a piece of brass tubing.  The OD of the tube is a pretty good match to the size of the trough.


















Cleaned up the ends and filed it roughly to the length of the trough.  Exactly length not terribly important.


















Slit the tube in half.


















Deburred the edges with a small file.































The brass insert will take up the excess space in the trough.


















Coated the trough with J-B Quick Weld epoxy.


















The sleeve in position.


















Pressing it into place allowed the epoxy to squeeze out and fill all the gaps around the tube.


















Gave the loading bolt a thin layer of grease so excess epoxy wouldn't stick.


















The barrel was installed and the bolt latched closed.  This held the sleeve in perfect alignment to the bore.  Gave it a couple hours to set up.




















Oh, there's still one more problem with the gun--If you look closely, the top of the casting is damaged at the front sight cross pin.  The sight is only held to the gun with the elevation screw.  I'll probably add a dovetail for a red dot.


The reassembly was done with a .22 cal barrel made for my S&W 78G.  So, now, my Daisy 790 is technically a Daisy 780.


















There's more epoxy on the right than the left.  Worked great as a filler.


















Semi-finished--and the bolt works!  Add that dovetail next time I fire up the mill.




Quick S&W/Daisy tip:   Removing the cylindrical retaining sleeve is often a huge pain in the neck.  Nick made a really nice tool for this the last time he worked on a S&W 78G.  I took a different approach a while ago and forgot to show it.















Ran a 5/16"-18 tap into the end.  I've done this when the sleeve was stuck inside the gun.  Got enough thread bite on the tap and pulled the sleeve out.  Once out, clamped the sleeve in the vise (in soft jaws) and cut five or six full threads.  Deburred as necessary.


















Important to make sure the threads face the muzzle when reassembled.  A standard 5/16-18 bolt can now be screwed in and used as a handle to pull it out next time it's stuck.




More soon.

Monday, November 19, 2012

Carbon Fiber Shroud for the S&W 78G Part 2 Final

Nick and I are on a S&W roll lately.   Regular readers will recall that I recently cut a new barrel for my 78G gun to replace the poorly rifled original.   Alas, it's far too short for this shroud project.  Well,  I still have a non-functional Daisy 790 waiting in the wings for repair, so the barrel doesn't have to go to waste.















Back to the S&W 78G shroud candidate.  This was a "Toys that Shoot" Findlay, Ohio airgun show find from a couple years ago.
















Basically just gonna make yet another--but extended--replacement barrel.  Lacking a piece of 16" long barrel scrap, a new Crosman 2260 rifle barrel will be sacrificed.
















Since it runs completely through the shroud, it needs to be about this long.

















Precisely cut with a hacksaw.


















Tapered the muzzle end.


















Started to thread the end 7/16"-20.  Later, I'll extend the threading and do final fitting from this end for length.


















Turned the breech end down to 0.382".  Did this in inch-and-a-half sections, so I was always working near the chuck to minimize deflection.  Likely could've done this on the larger lathe in a couple minutes, but, hey, it was 30 degrees out in the garage.



















Cut the leade.


























Spotted for the transfer port hole.


















Drilled 0.125".


















After some test fitting to finish the leade and ensure the bolt closed properly, I extended the muzzle thread for the shroud.


















Cut it to length.


















Crowned.


















This threads into the inside of the front aluminum shroud cap.


















Right around fifteen inches of barrel.  Almost double the original barrel length.














Installed.































Can't see it here, but there's a thin o-ring over the barrel between the gun and shroud.  No metal to metal contact.

















Shroud OD was selected so as to not interfere with the iron sights.
















At least it LOOKS like a suppressed S&W.   The carbon fiber shroud is light enough to shoot offhand effortlessly.  I find the marginal weight increase to be helpful for stability.  The velocity has increased a bit more than 100 feet per second.  It's now up from 420 fps to over 530 fps with RWS .22 Hobby pellets due to the additional barrel length.  Accuracy is marginally better than before--but still substantially better than what the stock S&W barrel could produce.  Given that the sight radius is unchanged, I didn't expect any significant improvement in accuracy--at least not at 10 meters.  It'll be interesting to get it outside and shoot at 25+ yards where the added velocity should flatten the trajectory.



Continuing the S&W kick, my next project will be (Finally!) getting that Daisy 790 parts gun up and running.  It's been sitting for two and a half years.