Allchine Bibcox

[sbwhart]

A friend ask me if i could make hime some Bibcoxs for his 1 1/2" Allchine traction engine, Bibcox is the old fasion name for a tap.

This is the drawings




Tiny little buggers arn't they.

First make the D bit

Slew the compound over 3 deg and turn a taper on a length of silver steel, give it a bit of a polish. Now so that the cox matches the taper in the body perfectly don't change the setting of the compound until the job is finshed.



Section the D bit you want to make them just over centre



Heat them to cherry red and quench in water, I didn't bother with tempering them.

Give the flat face a rub on a smooth stone to get a nice sharp edge. I glued a collar round it to act as a stop.



Then in a bit of 5mm brass bar on the centre, put through a 2mm drill then follow it up with the D bit to cut the taper for the body.



Thats the hard bit done

Mill a 2mm square on the cox.



Chuck it up in the lathe and thread 10 BA and turn the tapere length, and the handle bit part off, and aneal it before bending the handle.

Put the body in the lath assemble the cox and drill through 1.5mm: remove the cox and finish turn the rest of the body and thread 5/32* 40 ME again aneal before you bend the spout.

To make the square hole washer make a 2mm square punch from silver steel just harden the square bit, turn up some brass washers with a 2mm hole in them and use the punch to knock the square bit out.



Thats it Job done



Stew

[Bernd]

Nice one Stew.

I want to know how you machined the end and bent it like that?

Bernd

[Rob.Wilson]

  very nice Stew 

looks dam fiddly work 

Rob 

[saw]

As usual a very nice job 

[sbwhart]

Nice one Stew.

I want to know how you machined the end and bent it like that?

Bernd

Very carfully

 

I've broke quite a few Bernd I found the best way was to aneal them first, but a still got a few brakes, so bent it part way then reanealed the only problem is they have such a thin section you melt them 

looks dam fiddly work 

You can say that one again.

Some more set up pics

Turning the taper and 10ba thread problem was getting the compound back to the same pint ended up putting a stop on it, you just had to turn engough taper so that the square pockes through the hole.



Also rigged up a magnifier, I also found that blacking the bit with felt tip help in seeing what was happening



After turning the taper seat pulled them out of the chuck a bit and turned the taper for the handle.



Parted them off anealed them and bent the handle this is only a part bend, I may leav them like this or aneal them again for another bit of bending.

Assembled them in the bit that will make the body and drilled through 1.5mm so the hole will line up





I'm making a few more so I'll post some more pics when I do the bodies.

Stew

[Rob.Wilson]

Looks Dam fiddly dose that Stew 

I thought you were holding out on a few photos   


Rob 

[Stilldrillin]

Tooo darned fiddly for me! 

Great work, as usual Stew! 

David D

[doubleboost]

10 ba 
Very nice Stew
I use a magnifying glass for 4 mill
John

[lordedmond]

 I thumb my nose at 10 ba 
I use 12 ba on a regular basis with the accessional use of 16ba :bug eye:


Stuart


BTW good work Stew

[BiggerHammer]

WOW! That is some nice work. I had wondered how those were made. Thank you very much for the post.

[Stilldrillin]

I thumb my nose at 10 ba 
I use 12 ba on a regular basis with the accessional use of 16ba.  

Stuart

BTW good work Stew

Stuart.

That explains why Stu & Stew are model engineers...... And, I'm not....... 

David D

[sbwhart]

Thanks Guys

12 and 16 BA Stuart that must be like tapping with an hair 

I supose M4 in a ship yard is very small stuff John 

I don't think I gave Bernd a straight answer to his ?

Nice one Stew.

I want to know how you machined the end and bent it like that?

Bernd

I thought I'd got lucky with the first one, I was right putting those bends in was a bit of a headace. I was using scap yard material I think it was leaded free machining brass so it wasn't the most ductile of the brasses hence i had to aneal it and bend it in stages, I also found it best no to drill the hole all the way through and to leave it blind that way the wall got a little support to stop it colapsing and turned the spout twice as long as required and cut the surplus off after bending.

Also found it best not to go with to sharp a bend I held the part in the vice and bent it with a bit of tube moving the tube towards the end a bit at a time so that it gave a gradual bend.

hope thats a better answer Bernd



I formed the midle bit of the body with a form tool



Ended up with these good ones



And this is some of the scrap



Back to the Simpson and Shipton now

Stew

[lordedmond]

Good work on the Bibcocks Stew

yes things get a bit thin at 12 and 16 ba, not to bad tho

tapping size for 16 BA is number 73 or 0.6 mm or good old 23 thou  and do not sneeze ( I use my version of a tapping stand )

most taxing drilling job of late we two concentric rings of 36 no. 80 with the inner ring offset by 5 deg.  broke ten drills doing the pair not to bad for 144 holes as I only had 1800 rpm available , next time I would fasten my flex dive system ( 25 k rpm ) to the mill


Keep up the good work I do enjoy your posts as you build at a much faster rate than I can do now First loco was six months the last is looking like ten plus years

Stuart

[AndyB]

Cracking Stew,

I am stunned and amazed...again..again...again

Your work is such a fine example to us all.

Many, many thanks for posting this, you make it look so easy; but, thank you more for showing the scrap. It gives me, for one, more incentive and confidence to keep going when it all starts going wrong.

Andy

[arnoldb]

  Great tutorial Stew  - I've been running some ideas through my noggin on making small cocks like these, as I tend to work on the smallish side of things too.  Your method is so simple compared to the half-formed stuff I had in mind... 

  - It's nice to see the bits that didn't make it too...  I was suspecting that there might be some; it seems that the smaller the workpieces get, the more they end up on the "re-use" pile 

 , Arnold