Spares / Seals for 1/2" Flood Coolant Pipework

SnakeyJ

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It it possible to source spare seals for this old style flood coolant pipe? The pipework is 1/2" OD nickel? coated brass and was installed on my Colchester lathe, but appears to have been common to many machines of this vintage (1970's).

1565887403955.png

I've looked around and all the modern flood cooling systems seem to use PVC hose and blue/orange flexible plastic ends - can anyone can tell me the particular name/type for this old school plumbing?
 

SnakeyJ

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I would bet that that just has O-rings in it.
They seem to be cylindrical nitrile rubber, but difficult to measure as these break up when removed.
 

Nutfarmer

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Similar set up on an old valve facing grinder. Found short piece of neoprene hose sanded down on a mandrel was the only thing I could find to work. Kind of trial and error on the fit. Kind of crude but the short piece of hose worked to replace the old packing.
 

SnakeyJ

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Similar set up on an old valve facing grinder. Found short piece of neoprene hose sanded down on a mandrel was the only thing I could find to work. Kind of trial and error on the fit. Kind of crude but the short piece of hose worked to replace the old packing.
That sounds a cracking idea - I probably have some silicon tubing that might do the job. Will check out the required dimensions.
 

Bob Korves

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Measure the I.D., O.D., and length of the gaps where the seals go, and then come up with something to fill the openings, with a bit of over sizing so they will seal. When you get the numbers of the openings, you might post them here, the answer might be easy for some of us when we see the numbers...
 

SnakeyJ

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Measure the I.D., O.D., and length of the gaps where the seals go, and then come up with something to fill the openings, with a bit of over sizing so they will seal. When you get the numbers of the openings, you might post them here, the answer might be easy for some of us when we see the numbers...
Cheers Bob. I stripped the whole thing down today and some of the washers are in a better condition so I was able to see what was going on.

Each of the seals is made up of 4 separate washers, three fitted in the barrel of the compression fitting, then a sprung split ring that locates in a groove on the tube and then one more washer seating inside the union. Easier to show in the following photograph than to describe:

1565963634836.png1565963782713.png

The washers are don't appear very uniform, but probably distorted after 50 years in compression. Approx dimensions are OD=0.71", ID=0.5" and width is 0.1" - one face of each washer appears to be concave, but not sure this would be essential. I shall have a browse around and see if I can find any suitable sealing washers, but worst case I',m sure I can cut/improvise some from a suitable piece of silicon or nitrile rubber hose.

I shall probably customise the tap and fitting to connect two 1/2" BSP fittings, then I can mount some of the modern flexible outlets and retain the riser and tap.

I've now made and replaced the corroded foot plate of the cooling pump, using stainless rather than the original aluminium, and soldered up a cylindrical stainless mesh filter to collect and prevent the swarf recirculating. All working rather nicely, but it does spray a lot of suds around the workshop, particularly when working up towards the chuck. To catch the worst of the spray I've now fitted a rubber curtain to my chuck guard, which helps keep the floor and my feet dry ;)

1565964682163.png
 

Latinrascalrg1

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The "concave" is actually kinda important depending on usage and pressure. The concave allows the seal to expand under pressure and should be installed so that it is facing the fluid/air side or it will leak once pressure is applied.
 

SnakeyJ

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Having had a proper look, the washers I need are 0.5" x 0.63" x 0.1". I believe they were all propbably the same size but many are distorted by compression within the fitting.

The tap washers I got are very similar material 0.5" x 0.72" x 0.1", so in theory I can turn these down to size. However the material is pretty soft, especially as it warms a little and difficult to cut.

I've made up a mandrel and tried turning and sanding these down on the lathe. Sandpaper generates too much heat, but a sharp carbide bit seems to work provided I don't do too much at a time and allow things to cool back down...

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if you over do it the washers go soft, distort and split...

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Guessing I will just have to be patient and go slowly, but any tips would be most welcome :)
 

SnakeyJ

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loading the mandrel up and freezing it also seems to work rather better - please don't mention this to the wife ;)
 

SnakeyJ

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All done, dusted and back up and running - it all took rather longer than planned (a common feature in most of my projects), but I was able to turn down and use the cheap tap washers, so done cheaply and with no leaks on the reassembled flood cooling pipework.

A little trial and error, but freezing 6-7 washers on the mandrel allowed me to take 5-6 passes to reduce the OD from 0.72 to 0.64". Better to do this quickly, but the end result was uniform and clean.

It was a bit of a job reassembling and tightening the joints and I burred some of the knurling - must add a little strap wrench to the toolbox. However the joints are firm but move smoothly and don't leak. It's a little old school, but it works well and I can work with this. Though I might simply fashion an adaptor to allow me to add a modern flexible outlet on the end if required (I did buy 12 from China for little money, but will probably use these on the mill).

Couple of videos if anyone wants to see the washers being turned or the finished job. Thanks to everyone for their tips and suggestions with this.


 
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