Sunday, May 21, 2017

Mrod Air CP1-M Modifications

Started what I thought was going to be a fast project with my CP1-M pistol

Since it's been wearing a red dot of late, I removed the muzzle weight and front sight.  

A piece of 12mm ID/16mm OD carbon fiber was cut to something like 7.5" long with a hacksaw.

The tape is to protect the carbon from being scratched by the lathe jaws. 

Squared up the ends.

Not shown, I turned an insert for the muzzle end of the shroud. 

Epoxied into place then finished to the same diameter as the carbon tube.


I'm not a huge fan of the stock grip.  It's finished well, and I actually like the raked angle for target shooting, but the odd flare at the base doesn't do anything for me.  And I mean that in both the functional and aesthetic sense. 

So, I sanded off the flare.

Then started adding finger grooves.

Used a paint stripper to remove the remnants of the factory finish and kept on shaping.

Got a bit too aggressive (and inattentive) and sanded through at the web into the inletting.   After some choice cursing, I filled the hole with a mix of superglue and sawdust.   This is a pic of the repair.  I had a few ideas.  Maybe it'll look like a knot hole.  Maybe I'll spray the grips with truck bed liner.  Maybe I should stop butchering wood. 

Still smarting from the mistake and looking for redemption, I cut a small piece of Brazilian rosewood.


And glued it to the base of the grip.

A few minutes of power, then hand sanding, brought it to here.

The repaired area is glass smooth.  

Real woodworkers claim that when working with rosewood, you're either allergic to it, or you will be.  I've had reactions in the past--similar to poison ivy--that required a few rounds of steroids.  A dust mask and rubber gloves are never a bad idea.

Burnished in a very thin coat of shellac, then applied several more coats over a few days.  Used a fine Scotchbrite pad to level the finish.

The repair turned out...OK.  I don't feel redeemed, but the grip fits my hand far better than before.

Thanks for checking in.  More soon.

Sunday, April 30, 2017

Carbon Fiber Sleeve on the IZH 61 -- Part 2 Final

With the barrel sleeved in carbon fiber, it was necessary to make a new barrel band with a larger bore.

The IZH barrel band allows for mounting an open sight.  Not gonna bother with that.  After sleeving the barrel and pondering a new barrel band, I found this excellent post on the Canadian Airgun forum.  Mr. Samija has apparently already gone down this path while tuning a model 61 for his son. He certainly did a much cleaner and tighter tolerance job than I.

Despite my recent problems machining plastic, I bought a 1" diameter piece of acetal from McMaster-Carr.  Think it was under $5.

Lacking a 15mm drill bit to match the OD of the carbon tube, I considered boring to size on the mill, then remembered to cross check the size against fractional bits.  15mm = 0.5905", 19/32 = 0.5937  I can probably live with a couple thousandths clearance.

With a .500 edge finder, I found the side of the rod, then dialed in 0.750" to be on center (1/2 the edge finder tip diameter + 1/2 the diameter of the work piece).

Drilled a hole in each end.  Figured I'd screw up at least once.



Test fit then cut the ends off to what I think is 1/4" too long.

The original barrel band was not the correct height for the threaded hole in the breech.  Was hoping it was, so I could simply make this to the same center line height.  Nope.  

Started to get all fancy with my measurement, but the thought of measuring the top of the forend on the gun to the center of the threaded hole in the breech started to make my head hurt.

Gonna wing it.  Drilled for the mounting screw.

Flipped and faced the top.


Test fit. 

It looked like the height was off by about 0.020". This is actually closer than the factory band, but not close enough.  Went back to the lathe and stepped the OD to make it a bit slimmer.  Then made the base even shorter.  Scuffed it with a maroon Scotchbrite pad in an attempt to match the IZH finish.

Actually went shorter, because I didn't have a 0.020" washer, but I did have some acetal washers that are about 0.050".   Found that it's often easier to source a thicker washer than one made from what amounts to shim stock.

Used the assembly itself to approximate the correct height. 

Here's the amount the barrel needs to come up.

Washer installed.  The finish looks like an acceptable match. 

Don't see an alignment issue, so it's done.

A few glamor shots.  The wisteria over the deck is in full swing and dropping blooms everywhere.

So, the IZH continues to evolve.  It's now very close to what I envisioned for this little rifle.  Still want to make a shorter muzzle brake and spend more time shooting it.

Thanks for checking in.