Scubapro mark V

[oceancurrent]

nope. this didn't do the trick

 

[redacted]

Folks, what is the best method for separating the HP seat on MK 5 first stage from the seat cap with minimum damage? There seems to be a tiny hole in the back of the cap, but I am not sure if it goes all the way through to the seat. I tried sticking a needle in it but it hit a hard surface and didn't do much... Many thanks!

That hole does go all the way through. You can use a standard air nozzle (like these: Blow Guns, Air Chucks and Air Tool Fittings and Accessories) directed into the little hole to blow the seat out. I only remove that seat if I plan to replace it. If the seat is still working OK, I just do a little light cleaning and reinstall the seat retainer with the seat undisturbed. Disturbing the seat will result in multiple grooves and tend to produce IP creep.

 

[oceancurrent]

I found an air gun and that did the trick. Thanks

 

[oceancurrent]

Just finished my MK5 and it works like a gun (good IP, no creep). Big thanks to all for the help.

Now to my next project... I have an MK3 which looks great, but the IP keeps creeping. I took it apart and cleaned it thoroughly. The O-rings seem perfectly reusable (there are only two of them). The seat is useless though on both sides and I suspect that it is the cause of the problem. I don't think that either of the O-rings can cause IP creep due to the design (both O-rings isolate IP and HP from ambient water but not from one another; only the seat separates HP from IP).

I love the compact design and the super-simple mechanics (although it is not balanced). I am thinking of keeping it and replacing the yoke with a reinforced high pressure one. Now, if I can only find a replacement seat for this guy... Does anyone know how to get MK3 seats? Also, I am thinking of stocking on MK5 flat seats if I can find a source.

 

[DA Aquamaster]

The MK 3 seat is fairly generic. SP uses the same seat in all their unbalanced first stages and other unbalanced first stages of other brands often use the same seat.

The flat Mk 5 seats were also used by TUSA (licensed version of the same reg) and the current concave MK 10 seats are also used in the Mk 5 - and probably increase the flow rate slightly.

 

[kittyhawk]

Those HP seats are made of Tecamid 66 (Nylon 66). If you are handy and have access to a machine shop, it's so easy to turn one up. I had a collection of Mk5s and genuine service kits from SP and Oceanic.. I cross substituted them with those that I cut myself to the same shape using Nylon 66.. and could not tell the difference..

Restored a hp piston knife edge on the lathe as well. Someone mauled one of those... made an adaptor and put the piston in the lathe and very finely cut a new knife edge and lapped it. IP creep disappeared..

The adaptor is basically an aluminium cylinder with a hole the same diameter as the piston. and a slot cut, so that the piston slips into the alu adaptor and and the whole thing can be clamped in the 3 jaw lathe chuck... So don't throw those HP pistons away.. They are easily restored by your friendly engineer... it takes all but 2 minutes..

I was given the turret bolt specs recently.. if anyone is interested, I can have a batch made up in stainless steel... for those who need it.

 

[halocline]

I was given the turret bolt specs recently.. if anyone is interested, I can have a batch made up in stainless steel... for those who need it.

I would be interested in a few MK5 turret bolts. I'm sure we could get a few folks together in the states to share costs.

 

[Luis H]

Below is a mechanical drawing for the turret bolt.

I would also be interested in a few, but I couldn’t get a quote to have them made for what I thought that would be a reasonable price, in small quantities.

 

[HenrikBP]

Count me in for a few if a small run ever gets into production.

Henrik

 

[oceancurrent]

I would be interested as well.