Rebuild kit suppliers

[Karl Marx]

I want to rebuild my own regulators. I've found a supplier of ScubaPro kits; now I need a supplier of Atomic, ProSub and US Divers kits.
I'd appreciate any friend of a diveshop who will arrange to obtain the kits and protect the diveshop's identity.

I'm rebuilding my ScubaPro MK20. It's been an interesting experience. First off, it's not that hard. You must be very careful, but, if you take your time it's not hard to be careful.

I made a mistake that was highly educational. There is a "bolt" that attaches the "turret" that allows the hoses some flexibility from the fixed part of the 1'st stage. That bolt is made of brass and has a hole thru the shaft. It's very delicate and should be torqued to manufacturer's specs. In my case, about 62 inch-pounds.
I bought a torque wrench, but, it seems to have been defective. I put quite a bit of pressure on the wrench, more than I thought was 62 inch-pounds. Fortunately, the "bolt" broke; i.e., I ripped the head off the bolt, before the torque wrench released.
I bought a new torque wrench and will try again. All I lost was the cost of the first torque wrench and the cost of that part.

Now, the really interesting part of thestory. I've discussed my experience with two scuba reg techs. Both told me that they didn't bother to use a torque wrench. One told me that he has never ripped-off the head of this bolt; the other said he has done so occasionally.
If the second guy has ripped-off the head of the bolt occasionally, how many times has he used too much pressure, butnot quite ripped-off the head? Maybe never. Maybe he only uses just the right amount of pressure, or enough more such that the head breaks. Skeptic that I am, I'm inclined to wonder whether he might have occasionally have done some damage to the bolt but not ripped the head off. If so, there might be a regulator out there that has been stressed beyond the point of maintaining it's mechanical integrity. Maybe it won't break; but, it might.
The other guy might have never applied too much pressure to have ever damaged the mechanical integrity of the bolt. How would I know?
What I do know is that these two techs are "winging it" without a torque wrench. If these two guys are doing so, how would I know whether the guy working on my reg uses a torque wrench.
Bear in mind that if that bolt breaks, the turrent will be "fired" like a bullet with 150 psi of pressure in a straight line with volocity diminished by only 3 inches of water until acted upon by an opposing force (i.e., the back of my head). Enough to kill me? I don't know. Enough to knock me unconcious for a minute and drop my regulator? I don't know.
I don't want to find out. That's why I'd rather do it myself.

Thanks,
Karl

 

[pipedope]

Please don't use the torque wrench to remove bolts. This will generally overstress the torque wrench and make it inaccurate.

Remember that torque specs are for assembly of clean parts.

If a bolt does not come loose when you think it should, STOP.
Try to find out why and if there is something you can do to solve the problem without simply using greater amounts of force until something breaks loose or simply breaks.

Yep, this is one of those experience things but I use a rule of thumb of something like 3 or 4X the torque value for assemble to break loose. If I get to 3x I will stop and see if I need to do something else. That 62 inch-pounds is only a bit over 5 foot-pounds. That is not very much. Example, car lug nuts usually call for 90-100 foot-pounds and I rarely need more than about 150 foot-pounds to get them loose, unless they were overtightened when put on. On my vehicles they are tightened with a torque wrench.

Do you have Vance Harlow's book?
How about the one from Peterbuilt?

 

[donclaypool]

o.k.

Call me the idiot here, but I have to ask. 62 in/lbs is only 5.16 ft/lbs. Thats 5 lbs of pressure on the end of a foot long wrench. Were you using a wrench calibrated in INCH POUNDS? Did it break during disassembly or reassembly?

Don

 

[Karl Marx]

Thanks so much for your reply.

You mis-understood. I didn't use a torque wrench to DIS-assemble the part. Why do so? There is no point whatsoever to use a torque wrench on dis-assembly.

I used a torque wrench only to RE-assemble the parts. The wrench I used was one where you set a desired level of torque and apply pressure until the wrench gives. With such a wrench, either you rely upon the wrench's "calibration" or you guess. I decline to guess. I didn't buy a torque wrench to guess whether it's right/wrong. I bought the torque wrench to be correct.
Either the wrench was defective, or, I experienced "user error".
I bought a new wrench that is the old-fashioned "beam" type; i.e., it just bends and a "needle" points to the measured amount of torque. That should elimonate the user-error problem (unless I just don't look).
Regards and thanks.
Karl

 

[Karl Marx]

Thanks so much for your reply.

I didn't use a torque wrench to DIS-assemble the part, only to RE-assemble the part.
In torquing the re-assembly, I wouldn't try to torque it a bit past the mid-point of the recomended range.
Regards and thanks,
Karl

 

[Karl Marx]

Thanks so much for your reply.

Yes, of course, it was calibtrated in inch-pounds, not foot-pounds. The maximum range was 200 inch pounds. So, I was using about 1/3 of it's maximum capacity.
The new wrench I bought is calibrated to 60 inch-pounds. So, I'll be pushing it just a tad beyond it's calibrated capacity to a couple of inch-pounds above 60.

I was RE-assembling the parts, NOT DIS-assembling them.
Regardsand thanks,
Karl

 

[Coo's Toe]

Where are you getting Scubapro rebuild parts? I've been searching for a while, and still haven't found a source. Can you help?

 

[redacted]

After putting enough stress on the turret bolt to strip the head off, you might want to consider replacing the turret in addition to the damaged turret bolt. This would guard against an incipient failure due to stressed threads in the turret. DA Aquamaster seems to be quite helpful on these things. You might want to PM him and see what he recommends. Hopfully I'm just being over cautious but.... Please let me know what you learn.

When I picked up a 1/4 inch drive torque wrench on e-bay, I tested it against my 3/8 dive within their overlap range just to make sure there wasn't a gross problem.

 

[docmartin]

turrets, the source of all evil.

 

[scubatech]

Some of the very first nuts were made of brass. This in it self is not a problem. The problem lies in when some service tech that doesn’t know what a torque wrench is over tightens the nut. Sometimes it breaks right away (they tell you something was wrong with it and charge you for it) other times it just gets over stressed and breaks on pressurization, or breaks on the next disassembly. Scuba pros solution to this was to replace it with stainless steel. Hopefully this will shed some light on your problem.