9.0mm vs 9.5mm OD barrels

CHGBBS order has arrived…very pleased with the bits (some more metal for the m24)

the SS barrel though is a 9.5mm OD which if i’d done any reading i could have prepp’d for…as the m24 t piece is suited to 9.0mm OD barrels.

so before i take a dremel to my new T piece…

how are we all boring out the 9.0mm holes to 9.5mm ?

I reckon heat up the barrel end and feed it through the holes, they should flare the plastics nicely

metal…all metal…

Secure some heavy grit sandpaper like emery tape onto the barrel end and rotate it as you feed it doen the outer barrel, use a hand drill to speed things up

Or use an old 9 od alloy barrel and glue the sandpaper to it for more security and same technique

yea…that would be the dremel solution.

i have a small drill press style stand for it…rawks

but if someone else has a better way…i’ll adopt that way

It would help if you could get your hands on a 9.5mm reamer thats 70cm long but no such piece exsits

i only need to do the t piece so… 30mm at most.

thinking a nice drill bit though

A 9.5mm end mill is best, you can use it in your drill press just make sure its perfectly lined up first by putting a 9mm drill in the chuck upside down then put the t piece on it then clamp it in position then lift the drill press up and remove the drill, it will then be centered and aligned at 90deg. Then use the end mill.
Or if you have a lathe just machine the end of the barrel down to 9mm where it goes into the t piece


You could try putting the barrel in the freezer over night then put the t piece in hot water and possibly with minor effort it’ll almost be a neat interference fit? I do this when fitting ball joints, metal cased bushes in cars and trucks etc.

If you havent got much in the way of tools, you could spin the barrel by the muzzle end in a power drill on its side, with the barrel rotating in a pair of wood V blocks… then use some coarse emery paper then finer sand paper… or a file to reduce the od of the barrel where it goes into the T piece Yoda22

The T piece could be drilled up a tad or emery paper around a spindle inside the T piece for the barrel to go in… then do what Dave said, barrel in freezer and T piece in boiling water or hot oven and press the T piece onto the barrel like

1 Like

I ended up using a drill and bit.

I couldn’t get the t piece to center on the lathe.

Rough but reasonable result. Lathe would have been perfect.

1 Like

You can run the lathe or drill backwards, so the drill doesn’t bite and tear into the metal T piece… so the drill creates heat and wear rather than cutting…

If you drill into plastic or perspex, running the drill backwards stops the drill biting and cracking… the drill bit gets very hot :+1: