Daisy 747 rebuild

Sorry about the dearth of postings lately.  I recently made a career change and found myself working two jobs for a couple months before taking the plunge.  There was simply no time for anything else.

One of my friends sent me a Daisy 747 to have a look through.  The valve wasn't sealing properly on the compression stroke of the lever.  You can generally assume that's the problem when the air is coming out of the barrel during charging or immediately after.












It's Matt's 747!

The basic tear down is identical to the 717 and 727 guns that Nick and I have previously covered. 

I cycled and dry fired it a few times.  It was immediately apparent just how much better this adjustable trigger is compared to the trigger unit in my 717 model.

The adjustable piston head had the typical chewed up notches.  Daisy should really make this from something more robust than a zinc die casting.

Left panel removed.

Pump lever removed.

The compression tube is aluminum.  I'll have to check my older 717, but I think the older guns have brass tubes.

Piston head.  I don't think this seal is bad, but it still gets replaced. We're this far, so why not?  This o-ring is a #115, by the way.  

Injection seam from the mold.

This flashing is the problem with using a die casting.  I found pieces ranging from dust sized to this throughout the compression tube.  Most of it was on the piston.

Chucked the head in the Taig and took a clean up pass to remove the seam.  Also cleaned up the adjustment notches.

Here's the likely leak offender--the valve stem seal.

I stoned off the face of the valve both to square it up and remove any potentially loose casting material. 

This o-ring seal is also not really suspect, but like the other, it gets replaced.  And like the piston head seal, it's also a #115.

I used a grease on the o-ring seals.  Should last longer than the oils that are typically used.

Matt supplied a repair kit when he delivered the pistol.  The valve stem seal is an earlier design. 

Looks like it's been sitting around for a while.  It's probably 20 years old.

Fortunately, I bought several replacements from Daisy when I was fixing my 717.  Because one is none and two is one...

New style on top, old on bottom.  My guess is that they're actually interchangeable, but I'd prefer to take one more variable out of the equation.

Reassembly was simply a reversal of the procedure.  Did grease the cocking linkage with moly as well as re-stake the cocking lever pivot pin.  (It was so loose, it fell out of the cocking arm at one point)  Not shown:  Polished and cleaned up the trigger pull a bit more.  After all this, the gun still had a tiny leak when initially charging the gun.  Went back in and reseated the valve stem seal using some minimal pressure to get it to conform to the valve seat.  A week and 100 shots later, there's not even a tiny hiss of air when charging--all the air is now going (and staying) inside the valve. I still want need to chrony the gun before sending it home to Matt.

Really astonished at how superior this trigger is compared to the one in my gun.  Looks like the grip frame is different as well as the trigger itself and trigger return spring.  I'm calling Daisy and upgrading the parts in my gun next week.  The 747 is absolutely worth the $40 premium it brings over the basic 717.

Thanks for checking in.

Quick Set of Walnut Grips for a Crosman 2240

I've built up several (OK, too many) Crosman 22XX based pistols over the last few years.  Largely because they're so inexpensive, perform better than the dollar amount would indicate, and readily modified due to their modular construction.  But the plastic grips--I just--hate them.  So, every few months, when the mood strikes, I try to knock out another set.  Lacking a duplicator, these are all done by hand--for my hand.  That seems somehow appropriate.

As this is grip set number I don't know covered here, I'll just give a brief recap.

Cut the basic shape out on a scroll saw, then used the milling machine to cut the inletting for the grip frame. 

Also counterbored for the grip screw bosses.































Marked, then drilled the grip screw holes as well as the associated counterbores for the screw heads.

Drilled for the small anti-rotation posts at the top of the grip frame.

Then it was shaping time.  Everything up to this point counted as tedium.  Used various sanding drums in the small bench top drill press and freehand the shapes.  There's a lot of blending to get the curves to flow into each other.

And they're almost done.  Some finish sanding, grain filler and stain were next.

Gave the grips about three or four coats of Birchwood Casey Tru-Oil.

Moments before knocking off the shine.

Some bronze wool then a waxed rag left a matte finish.

About two evenings in these for the shaping and sanding.  Another three days or thereabouts for the finish--mostly drying time.  Still need about four more sets of grips--or fewer air pistols.



More soon.

Another Breech for a Crosman. Part 5

The aluminum breech went together without any real problems--that alone left me filled with wonder and amazement.  Gonna shoot it for a while before deciding what to do with the shroud.  The blank aluminum tube seems to beckon for some kind of adornment.  Sprayed the grips with a couple coats of truck bed liner.  I actually made a pair of wood grips, but I didn't think they fit with the black and silver colors.  The Tasco ProPoint dot carries the color theme.  Shoots great, but I have a feeling that this will be one of those project guns that evolves every couple months and is never truly finished.  I already miss not having a bolt hold open.  Next time it's apart, the loading bolt is getting a rare earth magnet.
 

May throw together a short post showing those aforementioned grips if there is any interest.

Thanks for reading.  Check back in a few days for more.

HW50S Rebuild, Part 2

Ok, 2+ months between installments, but at least I’m posting! This is boring anyway as all I really did was sand, sand, sand, and sand some more, trying to remove the worst of the rust pitting while not digging in or ruining the lines of the gun.

Starting to sand, I kept the strokes in line and used a variety of sanding blocks so as to not put flats on the tube.

Better. I gave up on the idea of eliminating the pits entirely, chances are I would have ended up sanding through the tube!

Sanded this as well. Those deep gouges will remain.

This is some deep pitting too. Not much can be done about it.

I found it curious that the breech face has those deep milling/sanding marks that look as though they are from the factory.

Still sanding. The barrel had some bad spots and again I didn’t want to make it look non-cylindrical. All told it was a month or so of sanding, usually for 5-15 minutes a day as it’s boring and I’m too darn busy these days.

Put back together for testing.

I still need to make a replacement screw for the trigger guard.
I blued the gun with Oxpho Blue from Brownells as it seemed to react best. I had washed the gun before that with Ospho, which is a phosphoric acid paint prep, in theory this converted the rust to iron phosphate and stemmed the worst of the rusting. We’ll see.

Depending on the angle of the lighting it looks grey to blue. Notice the vestiges of the old blue in the bottom left corner.

From a distance it doesn’t look bad though. I was able to use the new spring Derrick sent me even though it had more coils. I sparingly lubricated the gun and did a basic cleaning of the trigger unit.
Shooting 7.9 gr. CPL pellets over the chrony I got between 575 and 599 fps (599 was the first shot, a bit of dieseling) with it settling between 575 and 585. Not bad, I bet it will get a bit slower over time.
Now to work on repairing the stock, see you in another month or so!