Fowler BB1 in 2"

[Jasonb]

Jo, was that not meant to be concave rather than Convex? or have you decided to do the top part first as a fabrication rather than from solid.

You could have just selected radius on the DRO rather than doubling all the measurements, its a lot less buttons to press.

J

[Jo]

Care to share your Excel spreadsheet or the link?

Chuck

Chuck: the spreadsheet is good but has its limitations so I was going to have a little hack re-write 

Jason That's the ball still attached to what is going to be the socket as it gave me something to hold in the chuck  I could have used a much bigger piece of metal, made much more swarf and had less than 6mm to hold it on in a 4 jaw chuck. The Forecarriage ball only requires those two ears silver soldered on and this piece of steel was just the right size  so why not use it? And of course I can now use the socket to hold the piece for the next job 

No buttons at all to press: I printed out the measurements from the spreadsheet as Diameters not radi.

Jo

[kvom]

Do the socket on the mill with a rotab and a ball mill.  You just need to do some trig or CAD to figure out the depths and radii.  Roughing can be done with  normal endmills.

For CAD, I'd do the following steps:

1) draw the profile of the socket
2) now draw another curve with the same center but radius shorter by the radius of the ball mill to be used.
3) Now draw either vertical lines or radius lines separated by the distance for each pass.
4) The points where these lines cross the ball mill path are the coordinates to be approached when milling.  Use the CAD's dimension facility to determine those points' coords.

[Alan Haisley]

Perhaps a flycutter with a tool ground to take a horizontal rather than angled cut. Set the cutter to match the radius of the socket. Mount the socket material in a chuck mounted on a vertical rotary table.
Move the cutter in a bit at a time and at each setting rotate the table 180 degrees.
The only challenge to this is getting the flycutter radius set. Possibly a template would work.

Alan

[Jo]

The ball requires to have a taper in the centre and to get both it and the perch pin the same angle they needed to be done at the same lathe setting. So pin first . The taper was set up by using feeler gauges to give me the required 0.8mm after 17.5mm:



As normal I used marker pen on the work item to see the taper appearing and to know when it was complete  :



The marker pen also showed when the die reached the bottom of the taper:



With the taper done it was time to mount up the ball and cut the taper. You will notice that the tool is mounted upside down. This is because this is being cut on the rear face, not the front.



Check it fits:



I also scribbled a note to myself on the perch pin that the thread is 1/2" * 26 TPI  that is going to be burnt off in a while when the end gets silver soldered on.

Jo

[smfr]

Ooh, I like the use of the feeler gauge to set the taper; mentally filing that away for later use. 

Simon

[zeeprogrammer]

The taper was set up by using feeler gauges to give me the required 0.8mm after 17.5mm:

What was the process?

I can't mentally file like Simon. That cabinet is more like a bin.

[Jo]

Thanks for looking in

Zee: You get the tool to just scrape the bar at the end then using the top slide wind to the end of the taper. Measure the gap between the tool and the work piece. I needed to go from 12.7mm up to 14.3mm so I needed a gap at the far end of 0.8mm. Once the feeler gauges just fit lock everything up 

A bit more swarf  :

When I cut the ball I had to set the tool up to follow a radius of 45mm, that's the radius of the work plus half the tool diameter. Now I want to cut the inside so, don't do what I first did and use the same measurements in reverse  The tool needs to follow a curve of 35mm radius, that's the radius of the work minus half the tool diameter:



To get a 10mm diameter tool that had the clearance like a boring bar I used a ball end cutter. Carefully mounted so the cutting edge was horizontal:



I also angled the tool holder to about 30 degrees so that I was cutting on the side rather than the tip of the ball cutter as there is more cutting surface there. As I cut again I used my marker pen so I could see what was happening:



In the end a socket to go with my ball:



To clean it up I used the dremel on the inside face:



I tried the fit but the blue didn't shown anything it seems good, on the full sized engines the fit was achieved by throwing some sand into the grease and let it wear in



Still a bit more to go but the parts are appearing:



Hopefully I can finish those tomorrow as I am on holiday

Jo

[kvom]

The taper was set up by using feeler gauges to give me the required 0.8mm after 17.5mm:

What was the process?

I can't mentally file like Simon. That cabinet is more like a bin.

Start with the tool against the work (or against a feeler with known thickness), then move top slide left for the length of the taper and check the resulting separation.  Would be the same idea if using a taper attachment w/ carriage.  I do the same with my lathe's taper attachment easily given that there's a 2-axis DRO available.   I've also see people set the top slide angle using an angle block where the geometry of the tool post allows.

If the ball and pin are cut with the same setting, I'm not sure that super precision is needed since any taper would match.

[Jo]

To fit the socket on the plate it needed a slot cut in the back so first find the centre:



Then using a delicate little end mill carefully cut the slot 



The socket has reinforcing pieces so slots were cut in the plate to take these:



Then using the plate to square up the socket:



Similar slots were cut on the socket:



Which gave me a set of pieces ready for silver soldering together



As normal minimal flux and silver solder. I don't want to have to spend ages cleaning it up 



Whilst that was cooling off, I picked up the perch pin, now this needs a 4mm wide 9.53mm deep slot in it. The easiest way is to mill the slot:



Then silver solder on a suitable piece from the short end container, and turn to size:



I seem to have a reasonable gap for the washer left:



Now do I go out to play again after dinner and do the ball 

Jo

[Tjark]

Jo, what a great job to get the concave form.
Maybe you need one off this;


    Tjark.

[Kim]

Quite nice fabrication work there Jo!  I haven't posted on your thread much, but I'm enjoying watching and learning. 
Excellent work, as always 
Kim

[Jo]

Tjark: I can always find a home for a new tool 

Hi Guys, thanks for dropping in, we are nearly to the end of this little bit then I have painting  and another engine asking for my attention 

Jo

[Jo]

The ball has had four of its sides milled square but on two of them the ball's curve has been left, this is where the "ears" are going to go:



A bit of silver soldering later and they are attached.



Then get that delicate  little slot drill out and bring the back to the correct thickness and those ears:



Then turn over and counter bore/drill for the four mounting bolts:



Notice I am using a Autolock chuck, this has the advantage of providing positive positioning for the milling cutter as it holds the back with a point. I can set my DA collets up to do the same but ER collets won't do this for you 

  Not sure how I am supposed to get at the hex heads down those holes, I might use cap heads    So one assembly complete and you can see how much movement the ball joint can provide  :



And now for something entirely different 

Jo

[Jasonb]

Did they not use studs tapped into the top of the ball rather than bolts?