Fowler BB1 in 2"

[Jo]

There is already a recess in the outer hub plate for the hub cap (1.2mm) and the retaining collar (3.2mm), leaving the rest of the 6.35mm as bearing surface.

Jo

[Jo]

I needed to cut the angles at 30 degrees, thankfully I had a square of the right angle:



I also picked up a new toy  which enabled me to check the angle once it was set up in the vice.



Then came lots of milling, which one bit is like another The only possible interesting bit was the use of a large milling cutter which had had its corners rounded over to form the curve on the backs of the flange. So a large amount of swarf later and it is time to fit the hubs to the beam:



But not tomorrow as I am being taken out 

Jo

[Jasonb]

Is it my eyes or does the central section look too long. I recon that on yours the perch plates should be 20" long which equates to 3.33" or 85mm on the model and they extend to just beyond where the axle thins down which you have at 117mm? The pdf you sent me looks shorter than the metal??

EDIT just measured your drawing and the middle should be 89mm long not 117

I did the same on mine made it to Hainings widths then had to machine about 3/4" off each side.

Bring it tomorrow and I'll bring mine

[Jo]

Just checked    That was version 1 of the drawing I machined to. At least I still need to take metal off  rather than try sticking it back on 

If you want to see my bits you will have to come to the house 

Jo

[Jasonb]

I just came to teh same conclusion while you were typing that, its the one you drew in Augest thats correct not the previous February. At least you could round the internal corners now its only a quick Rotary table job to make the perch plates match.

Just your beam will do

[Jo]

We had a look at the beam problem, the concern is that, yes the original was forged hence the curves but if the replacement starts using curves and the perch pads curves are not exact  that there is a high probability of a dirt gap between that and the perch plate  which will cause rust  and the curve is only visible for 6.35mm of its height hidden down a gap between the two tool boxes 

Still trying to decide if the rust pocket risk is too high

Jo

[Jasonb]

that there is a high probability of a dirt gap between that and the perch plate  which will cause rust

They were never a good fit on the originals so if you create a rust trap you have done a proper job and got it just like the original.

Also if you don't round off at least the external corners of the axle then you will also have to have angular corners on the perch plates to keep a similar thickness upstand. Seems a shame to go to the trouble of redesigning every part of this engine to be like the original and then skimp on these parts just to make it easier to machine the top & bottom perch plates.

[Jo]

  I got the original BB1 drawings out and put my beam alongside and found  it was too long.



Now the Hanning drawings that I started with are      at times and I had forgotten that he had drawn the leading wheel built with the rims central on the hubs  As you can see from the drawing they are offset by 6.35mm. But more than that the entire beam is over length  by 25mm  So my nice flanges will have to be turned off 

I did have a little play with the curves in the centre. Not a nice thing to machine those curves it scaled down to needing a 34mm cutter and thankfully yesterday someone polished the last remains of the moths out of my purse by selling me this rather nice shell mill arbour which I just happened to have a 35mm shell for



I lined the cutter up with the line using a square, zeroed the DRO and then slowly proceeded to mill first the wrong side (climb milling  ) then the right of each end of the beam. That wrong side was  the cutter wanted to catch  I am now going to have to go and watch the race to charm my nerves before I decide how to proceed.

Jo

[Jasonb]

That looks better already, just as well I told you to look at that drawing.

You may also want to revisit your front spoke drawings and wheel assembly as your front wheels don't have any offset

J

PS do you want to know who won the race? 

PPS there is a programme on BBC 4 at 7.00 pm all about old british motor bikes, another of your passions

[Jo]

PS do you want to know who won the race? 

I have every confidence it was a handsome man driving a  car who is too young for me 

Jo

[Jasonb]

I think he is taken, but you can always dream

[Johnmcc69]

Hello Jo, where can plans for this engine be found?
You're doing a fine job.....

 John

[Jasonb]

Tyler Steam do the drawings but they will give you a "stand off scale" model and will need a lot of extra work to get a true representation which is what Jo has done.

http://darbysavage.blogspot.co.uk/p/fowler-bb1-ploughing-engine.html

The old copies of Model Engineer that covered the build of this engine also have the drawings

I have heard they are not teh best at customer service and would not like to use some of teh castings that they are now offering in aluminium when the patterns were probably designed for iron which is a more suitable material.

J

[Johnmcc69]

Thank you Jason. I would love to see the CAD models the both of you have recreated!
It's quite the project just doing that part of it.

 Who won the race? I won't tell Jo... 
 John

[Jo]

The article in Model Engineer does not contain the Hanning Drawings 

And whilst I have an original set of blue prints, Tyler is now providing photocopies of these original drawings and I have been told they are very difficult to make out

Jo