Tuesday, 16 April 2013

Sharp Innova Spacer, Made Out Of Scrap

Now i had the Sharp Innova up and running just dandy, and believe me i am totally impressed with how good this air rifle performs. I got to thinking about the missing spacer that sits under the compression tube in the breech, well it's got to be there for a reason even though the stock thread and grub screw seemed to be sealing the transfer port without it. But on second thoughts it would stop the grub screw scoring the compression tube and help even out the pressure from that point, besides i had a load of assorted tubing in the scrap pile from which i could cut a new spacer.

Spacer slips in under the compression tube out of sight inside the breech unit.

I had seen photo's of it on different sites that sold Innova spares, so i had a rough idea of it's shape and size. I measured the diameter of the compression tube which was about 22 mm then found the nearest sized steel tubing i had which was 26 mm outer diameter and 1 mm thick,seeing as it only covers about 1/6th of the circumference of the compression tube i could squeeze it a little to fit. The spacer starts just inside the breech unit and forks around the thread screw that holds the exhaust valve in place and the collar for the stock screw, then the grub screw pushes  against this and the square nut in it's housing at the bottom of the breech unit.

Cutting out the blank for the spacer

Holding the steel tube in the vice i cut two lines to roughly the right length, then cutting across ways i was left with a blank i could grind down to the correct shape. Putting a grinding wheel in the fonley lathe i ground down the sides so they were even, this done i then ground into the one end to create the fork that would sit around the threaded screw. Next i thinned out both edges along the length so the sides would flex a little easier and the thicker middle would push the tube upwards, then rounded off any square edges and filed off any remaining burrs finishing it off with some wet and dry.

Grinding on the fonley lathe (fonley means 'if only' i had a lathe)
It was now ready to slip into place once i had given the edges a little  squeeze, I had already removed the stock so all i had to do was loosen off the grub screw. It fitted in easily though it didn't quite slip in, i pushed it into place and pulled it out a little just to see if i could for future removal.

Rifle, stock, and home made spacer.. Grub screw and square nut in the middle.

Pushing it back into place i tightened up the grub screw and screwed the stock back on, that was it, job done. I know i could  of got one from Chambers or J Knibbs for a couple of quid, but the postage is a bitch on one item and besides it was easy,fun, and took no time at all.


Wing Commander Sir Nigel Tetlington-Smythe    

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