Working With Phosphor Bronze ........ Advice Please.

[Round in circles]

I am intending to make an adaptor for my power washers pond cleaning suction hood attachment . The base metal is die cast aluminium or similar.
The place where I have to attach the power washer hose is tapped to 19 tpi for a 1/2 " gas thread.

Looking carefully at the brass quick disconnect end spigot of the washers hose shows me that any brass part I turn up to make the connector will have about 1.5 mm of wall if I purchase a ready made union component & will be liable to snap off or rupture at this thin area the moment that it gets the full 150 bar of the power washer pushing on it .
Because the feed is 19 TPI my old Sphere lathe does not have the capability of auto carriage feed being related to the thread indicator on the correct place to start the threading passes.
I can do it all manually , it's a lot of messing about , but due to the cost of the PBA I'd rather not take the chance of messing up this little bit of work .
I can adapt a ready made & threaded union fairly easily by boring it through and having a 1 mm wall plus the gas thread sleeve which I can then turn up an insert of PBA for that will also include the spigot capture device.

So I have coughed up , released the moths from my wallet and purchased 150 mm of 30 mm dia phosphor bronze round bar to make a strengthener with a more common thread on one end to go inside the bored out factory made union and then add my home made adaptor with the same but internal thread on & sweat solder them into a single unit.

I've never ever worked phosphor bronze before ..had a play several times with various types of brass and found it was OK so long as I kept speeds & feeds down & if I remember correctly ground 3 to 4 degree cutting angles with 7 to 9 degree clearance angles on the drills used for drilling small tapping holes or boring larger holes .

In this Phosphor Bronze alloy ( PBA) I hope to drill two 4 mm holes for tapping and chain drill nine 2.5 mm holes to make a slot for the locking on device . In the main body that will capture the spigot end of the pressure hose I'll be running a 5 mm hole right through a piece of PBA that is 40 mm long, with a bigger hole at 11.2 mm dia and 24 mm deep .

Has anyone got any useful tips they'd be willing to pass on to me .

Dave

 

[kd4gij]

Can you make a drawing of what you need? not quit fowling.

 

[4GSR]

What little information found on the internet, it machines at about 20% of that, based on 360 brass at 100% machine-ability. Bottom line, if in the full hard condition, you are about to have some fun. If it's fully annealed, you have a better chance of machining it. I've never personally machined phosphorus bronze myself, but if I had to, I would start out using my favorite cutting fluid as a start. Try cutting the material dry at first. Probably run slow S.F.M. until a good feel is established.

 

[swatson144]

What 4GSR says, Though If I was to set it up in a cnc machine I'd cut into it at 2ooo rpm and feed about 9ipm which is pretty middlin for 140BHN Phos brnz, OTOH setting it up with my manual lathe in my garage I'd be about 860Rpm (my favorite voodoo speed) and somewhere around .oo5/rpm and see how it works. Each case is assuming carbide and about .02" DOC and a largish radius.

Steve

 

[4GSR]

............setting it up with my manual lathe in my garage I'd be about 860Rpm (my favorite voodoo speed) and somewhere around .oo5/rpm and see how it works. Each case is assuming carbide and about .02" DOC and a largish radius....Steve

I was thinking about half that, around 400 RPM, with carbide for turning and threading. Drilling with HSS +Cobalt, for the other holes, much less. Nasty tough stuff to machine.

I don't see why a piece of 17-4 or 18-8 would work just as good, and a little bit easier to machine.

 

[Round in circles]

I solved the problem by making a phosphor bronze alloy connecting part that was soldered into the metric 19 tpi hexagonal brass union and then used a 13 mm metric thread on the other end to connect into the steel adaptor block .
Yes it was interesting and very hard to run the die over it took me ages and ages even using special bronze cutting spray fort the die kept jamming every 30 degrees and had to be back off at least 180 degrees to fully free it ready for the next shaving .

The shaving can get very very hot without much change of colour . I got burnt by some that were on the tool post that I didn't think would be hot .

Once it gets to a very high temp they turn into a bluish purple reddish iridescent colour ..... leave them alone to cool as these stick to your skin when they come straight off the lathe & land on your hand .
At a low speed , slow feed it is easy to get a long thin curl of cutting coming off the lathe in one piece.
Do be careful as these are also very very hot .



Doing it this way making an adaptor instead of the whole piece means I have a lot of strength in the original very thin brass union

This is an over all picture showing the pond cleaning /hood device against a 330 ml coke can
The aluminium handle at the bottom is also my adaptation with out it it was nigh impossible to control /direct the cleaning head where I wanted it to go .



This picture is the nozzle on the end of the high pressure hose , the nozzle is located in the steel head ( In the above picture ) by a rubbed to thickness stainless steel BBQ skewer

The whole cleaning head works very well , I dropped the water level in the 12 x 6 wide pond by a good 6 inches in about seven minutes flat whilst taking out almost all the leaves and accumulated bottom crud in the pond of the last year . There is a sight problem in that the high pressure jet of water issuing from the jet inside the cleaning head has blown a hole in the ribbed plastic outlet pipe . So I'll be out & about looking for some thin walled 2 inch stainless steel tube to make a first stage outlet pipe that I can connect the rest of the plastic outlet to.

 

[Wreck™Wreck]

Wear eye protection, the chips will be shards aimed right at you, small hot and sharp. It makes a mess.

 

[Round in circles]

I certainly did , I also had bit of clear high spec poly carbon ( stripped out plastic British car number plate ) screwed to a strip of plastic that has four columns of three neodymium magnets embedded , so to hold it fast to the side of the saddle when I'm turning as a chip deflector but still the bits flew out and burnt me.. ..
Using a running coolant must be the answer instead of dry or spray oil cutting it .