Lathe Lust

[nikeajax]

Bill, eventually I'd like to get a drill press: amongst other uses for it, I want to add hose-ports to some of my regs I have a friend who is a master machinist at Cal (Berkeley) but he is nearly impossible to get a hold of

JB

[herman]

Oct 22, 2021 12:32:40 GMT -8 nikeajax said:

PY or Bill, what are the bits called that you use to make the recesses for the o-rings?



As can be seen in this image, especially so on the Scuba Star. I'd like to get a drill press one of these days soon...

JB

 I use a piloted counter bore and pilot, it's the best way I know of short of a "real" bit for the oring grove....they are very expesive.
Here is a place you can get them,  you need to order the counter bore and the pilot separately.  drillsandcutters.com/straight-shank-counterbores/ 
I highly suggest using a vise to hold the reg and do not remove it until you have everything done, including tapping the hole. this helps keep it all in line. I find it's best to drill the hole (Q drill by the way), then do the oring groove and finally the threads.  I also break the edge of the hole to remove any sharp edges. This helps the oring go in better and prevents cutting it. That said go EASY on the corner, too much promotes extrusion of the orings.

[vance]

Before getting a drill press, consider how tall it will need to be for your projects. As I mentioned, an x-y table is pretty much necessary for any accurate drilling. The table + a vise + the work + a drill bit will often be too much to fit under the chuck with a small bench top press.

I extended mine with a piece of exhaust pipe. It works, but it isn't rigid enough to be very accurate. If I didn't have the mill, which is tall enough for my needs, I'd get a floor drillpress.

[herman]

Agreed and keep in mind you should NOT move anything until you are done so make sure you have enough room to do what you need before starting to drill.

[antique diver]

Oct 23, 2021 8:05:17 GMT -8 nikeajax said:

Bill, eventually I'd like to get a drill press: amongst other uses for it, I want to add hose-ports to some of my regs I have a friend who is a master machinist at Cal (Berkeley) but he is nearly impossible to get a hold of

JB

I don't think I have the skills needed to safely add a hose port without risking ruining the reg body. I know you would prefer the neatness of an actual additional port, but you might consider one of the several types of multi-port adapters until you find an experienced machinist willing to take on the task.

[nikeajax]

He's the guy that did this for me:



He went just a tad deep, but, no harm, no foul!



He did it on a floor-press from the 1940's.

JB

[vance]

So, you're adding LP ports.

Does it leak? Is the o'ring groove not sealing, b/c of a too deep cut? Too deep will mean there's not enough meat left to seal. You mostly can't add material (w/o jumping through lots of hoops) that got cut away. A different sealing arrangement might be employed here. A washer/shim?

Maybe just getting another first stage body and starting over makes more sense?

[nikeajax]

PY, no, it woiks poifekly! Again, just trying to make conversation as well as educate myself on the workings of devices needed to perform such tasks. I have a bunch of other things I'm working on, but trying to keep our forum from becoming...



JB

[vance]

"How now? A rat? Dead like a ducat, dead."

It's Hamlet. Sorry.... Look it up if you don't get it.

Or don't bother.

But we aren't over yet! While things might be slow, we still plow ahead!

[nikeajax]

Ahh yes, death by a thousand cuts... But plow? You can't even call it a slink, or slither, it's all of a slight creeping movement... Time to reanimate the dead, yes, initiate... "Plan-9"



How's that for obscure?

JB

[herman]

Actually Bill, it's fairly easy to do. Just keep the reg level and don't let it move between steps.
The oring groove depth is not really critical since the actual sealing area is the interface between the bottom of the hose/plug and the upper rim of the port. As long as the hose/port will mate up with the reg, metal to metal contact and there is no space where the oring can squeeze out, it will seal fine. Putting a new port in the regs like the Scubastar that has flat areas it's easy, just bore the holes. On round regs like a Conshelf, you have to mill off a flat first then drill the port. If you look at any round reg you will see where the factory put flats on the body, you just have to duplicate them.

[technidiver]

Oct 23, 2021 11:26:15 GMT -8 herman said:

Oct 22, 2021 12:32:40 GMT -8 nikeajax said:

PY or Bill, what are the bits called that you use to make the recesses for the o-rings?



As can be seen in this image, especially so on the Scuba Star. I'd like to get a drill press one of these days soon...

JB

 I use a piloted counter bore and pilot, it's the best way I know of short of a "real" bit for the oring grove....they are very expesive.
Here is a place you can get them,  you need to order the counter bore and the pilot separately.  drillsandcutters.com/straight-shank-counterbores/ 
I highly suggest using a vise to hold the reg and do not remove it until you have everything done, including tapping the hole. this helps keep it all in line. I find it's best to drill the hole (Q drill by the way), then do the oring groove and finally the threads.  I also break the edge of the hole to remove any sharp edges. This helps the oring go in better and prevents cutting it. That said go EASY on the corner, too much promotes extrusion of the orings.

Herman, is this the bit required?

drillsandcutters.com/3-8-x-5-32-pilot-hole-hss-straight-shank-counterbore

And does the 5/32 refer to the pilot hole? I would be interested if you could expand more on the bits required to make the 3/8 o ring groove. I have a spare scuba star myself and wouldn’t mind experimenting on it.

TD

[herman]

I'm not home right not but pretty sure that is the correct counter bore.

You are correct, the 5/32 refers to the pilot mounting pin size. You need need a 5/16 pilot (closest thing unless you make your own, a Q drill is .332) for the Q drill so you have to work backwards. Find the correct pilot size (5/16) then pick a shank that fill fit the correct counter bore. As long as the pilot will fit the counterbore, the shank diameter does not matter. In this case, either the 1/8 or 5/32 pilot shaft would be fine as long as the pilot itself is 5/16.

So here is how I do it. I suppose it should be obvious but the reg MUST be dissembled, hitting any of the internal parts would be bad, plus the reg must be cleaned out well afterwards.

Tools needed.
Spot drill, 1/8 drill, Q drill, 3/8-24 taps (both taper and bottom), counter bore with pilot and some way to measure depth

1. Measure depth of one of the original holes.
2.Clamp reg in a vise on a mill or drill press. Get the reg as flat and level as possible, if it's not, the port may extrude orings. Center the hole.DO NOT MOVE the reg once you start.
3.Using a spotting drill, start the hole, this keeps the initial drill from wondering off center.
4.Drill the entire depth with a smaller drill, something like a 1/8 will do. Just punch through the center hole.
5.Using the Q drill, drill to the depth of the other LP holes.
6.Using the counterbore, cut the oring groove, this needs to be about 0.070 to 0.075 deep. If you don't have some way of measuring depth, bore down a little bit, insert an oring to see if it's deep enough. The oring needs to be just slightly below the edge of the hole. It's not critical but must be deeper than the oring is wide. (0.0625)
7.Starting with the taper tap, start tapping the threads, once the taper tap bottoms out, use the bottom tap to complete the threads. By using both, you are much more likely to get the threads straight. It's best if you put the tap into the drill chuck and turn it by hand until the tap starts to slip, them move to the tap handle. This ensures the threads are straight. You must use a bottom tap, most hardware store taps are the plug type and are not acceptable.
8.Remove the shape edge on the port, a larger drill bit can be used for this, BY HAND. Sand paper on the end of your finger will do. You want to barely round off the edge of the hole but not much more.
9. Clean out the reg, reassemble and test.

Hope that is not too long winded answer.

[nikeajax]

Some more tips:

First mark your spot on the regulator, with a pen or pencil. Next, use a small punch to mark the spot again. Lock the spotting drill bit into the chuck, then align the bit with the mark then lock that down and finally clamp the reg down tight, as Herman suggested.

To tap your new holes, lock the bit into the chuck: YOU ARE NOT USING ANY POWER FOR THIS!!!!! Lower the bit and turn the chuck by hand until your new hole is threaded.

Anyway, this is how my friend did it

JB

[vance]

So, true to form, I bought another Unimat that had some accessories I wanted that were lacking on my first machine. It's how I roll.

I always figure I can refurbish and sell at a profit. That's cool, but now what?

This one is missing some essential parts. The missing parts are for the milling function, so it is perfectly usable as a lathe.

I'm having a bit of fun trying to source some OEM parts, but these things are all about collecting. Simple parts are commanding insane prices (sound familiar?).

So, I'm looking at ways to make new parts that will work. I will keep you apprised!

Unimat mods, baby!