# Problems drilling phosphor bronze



## Cheshire Steve (May 14, 2010)

I bought some phosphor bronze rod the other day to make some tiny bearing bushes for the engine I am building - it is quite copper coloured, and different from what I have used before which might be aluminium bronze. I am drilling to 3mm and reaming to 1/8" with a D type reamer. Both are jamming. I had to use a blowtorch to get the drill out. I have no problem with brass or ally bronze, but this stuff is tricky. Any ideas on lube, modding the drill, etc ?


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## lordedmond (May 14, 2010)

you have some drawn PB102
it will grip down on to a drill with ease , it gets so hot it can turn blue

you will need to creep up on the size 

you will also need new unused drill bits good ones dormer or another good make not a cheap import
new reamers are a help also
a small amount of soluble oil will help

and finally drill with the peck method 

btw this site has some good drill bit with PS points http://www.greenwood-tools.co.uk/ishop/728/shopscr87.html
Stuart


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## Bluechip (May 14, 2010)

Steve

I've no doubt some people can deal with it. Not me. I gave up years ago. In fact, I threw a lot of drawn PB out to the Scrappy about 6 months ago.

For what bit I require now, I use Colphos 90.

https://www.maccmodels.co.uk/index.php?cPath=263_219

One UK supplier. There are others, I would think

Dave BC


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## Blogwitch (May 14, 2010)

I have to agree with Dave on this one.

I had a large production run of steam valves, and I attempted to do it in normal PB1 and PB2. Sometimes it would cut great, others just as you are finding it.

So I got a few lengths of Colphos, and never had a single problem after that. I knocked out 80+ steam valves in no time.






It is roughly the same price as normal bronze, but is limited in the sizes available. But well worth the effort to obtain it.


Bogs


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## boatmadman (May 14, 2010)

Until recently, my machining was mainly only prop shaft bushings, for which I used pB1 with the same problems.

Earlier this year I stumbled upon colphos here:http://www.nogginend.com/index_files/Page772.htm, read the material specs and though it had to be worth a punt.

Its great, easy to machine and gives a nice finish.

Ian
(very novice but learning fast!)


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## Cheshire Steve (May 14, 2010)

Oh you lovely people .. so it is not me being a novice .. this stuff really is hard to machine. Like I said I have no trouble with brass, can manage stainless most times, but this is a real pig !!!!

It was Noggin End who sold it to me at the kit car show in Stoneleigh, they are really nice people who do the show circuit, and must be on the road every day the number of shows they do. I assume it is not Colphos, I just asked for Phosphor Bronze - is Colphos copper coloured ?

I am inclined to stick to ali-bronze now for bearings - it is like brass, and I can deal with that. The pink stuff is a sod !!

Steve


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## Blogwitch (May 14, 2010)

Steve,

There are that many different types of bronzes it is very difficult to keep up with them. Many are made to do specific jobs.
That is why we have to rely on the metal merchant to supply us the correct type. 
If you come across a piece in a scrapyard, it could be almost anything. I have loads of the stuff I have picked up over the years, but I have been mainly rather lucky, as I have been able to machine all but one up to now. I remember about that one because it took out so many drills and cutters before I gave up and dumped it.

I doubt if you could recognise the difference between all these bronzes by colour alone. But just to answer your question, Colphos 'looks' the same as normally supplied PB1, but machines in a totally different way, dead easy, and silver solders perfectly.

Ali Bronze BTW is usually one of the hardest ones to machine (at least the type I use is), but is great if you can machine it, I use it mainly for big end blocks on oscillating engines, it outlasts anything else I have ever come across. Plus it is an absolute pig to solder up.


Bogs


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## Cheshire Steve (May 14, 2010)

I would take a photos of the stock that works fine (which I think is Ali-bronze) and this new stuff that is such trouble, but there is no point as the subtle changes in colours vary in photos.

I will put it to one side, and if anyone complains that brass is difficult to machine then I will send them some of this free as a benchmark !

Thanks, Steve


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## Cheshire Steve (May 19, 2010)

Just wanted to add that I got some Colphos and have made some more tiny bearings tonight with no problem. It drills, turns and reams like a dream. So thanks to everyone, the original PB will be hidden in a dark corner.
Steve


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## Noggin (Mar 13, 2011)

Hi Cheshire Steve,

   Just trolling through posts referring to colphos and found your thread.

   We would have sorted you out with PB102 up to 1/2" dia and PB1 over 1/2".


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