A Real Dirty Job

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Carrdo
Posts: 1114
Joined: Thu Mar 06, 2003 2:20 pm
Location: Toronto, Canada

Re: A Real Dirty Job

Post by Carrdo » Tue Jul 23, 2019 2:51 pm

Not to say that I have had enough "punishment" making the heart shaped links on the Josslin Hudson lead truck but now I am basically going to repeat the process all over again to machine the brake shoes on the Langworthy/Yankee Shop Hudson lead truck.

Normally, one would have had castings for these parts where much of the forming work is already embodied in the casting but since I have none, I will be making them completely from cast iron blocks. Again, lots of forming/profiling involved.

Since the model drawings assume castings to start with, all of the dimensions necessary to make them from scratch are not shown but there is enough information on the drawings to produce the parts from scratch. So, the first job was to produce a layout drawing where all of the additional machining information needed is shown.
Attachments
328 The Brake Shoe Layout Drawing.jpg

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Carrdo
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Joined: Thu Mar 06, 2003 2:20 pm
Location: Toronto, Canada

Re: A Real Dirty Job

Post by Carrdo » Wed Aug 14, 2019 11:11 am

The start of the lead truck brake shoe machining.

As indicated many times before I start by " rectangularizing" the CI brake shoe blanks to the best of my ability often using the surface grinder.

As I have machined Hudson brake shoes before, I have some fixtures already made to do this but, as usual, each individual model Hudson design shows slightly different forms of brake shoes to be made.

The first operation on the blanks was to machine the front shoe radius conforming to the diameter of the truck wheels which in this case is 2-1/4" which gives a brake shoe radius of 1-1/8" as per the Langworthy print.

Fortunately, my rotary table has a central tee slot which allows easy radial positioning and holding of the brake shoe fixture made and the blank itself.
Attachments
329 The CI Brake Shoe Blanks.jpg
330 Brake Shoe Blank First Machining Operation Radiusing.jpg
331 The Brake Shoe Blank Holding  Fixture.jpg
332 The Fixture Underside.jpg

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Carrdo
Posts: 1114
Joined: Thu Mar 06, 2003 2:20 pm
Location: Toronto, Canada

Re: A Real Dirty Job

Post by Carrdo » Wed Aug 14, 2019 12:19 pm

The next machining operation on the blank is not so easy at all and I really had to think about it for a while and to be a bit inventive. I tried to keep it as simple as possible but it didn't quite end up that way as what I came up with is a bit of a Rube Goldberg.

The large central plug fits both the centre plug hole in the rotary table and its upper portion is the diameter of the lead truck wheel. It is there to keep the brake blank truly radial on the rotary table. The side angle clamp pieces are tapered on the ends both horizontally and vertically to exert both a clamping and slight downward force on the brake blank piece. The large toolmakers clamp gives an extra clamping force.

Not seen is a support spacer under the brake blank piece itself to keep it from tipping as the blank, in the position it is in is right over the intersection of two tee slots in the rotary table, has to be supported here.

You will see why everything needs to be this way with the next machining operation.
Attachments
334 The Brake Shoe Blank Second Machining Operation Setup.jpg

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Carrdo
Posts: 1114
Joined: Thu Mar 06, 2003 2:20 pm
Location: Toronto, Canada

Re: A Real Dirty Job

Post by Carrdo » Thu Aug 15, 2019 3:08 pm

Machining, machining, and finally a roughed out brake shoe blank.

Nothing moved at all with this setup but I did take light DOC's (0.005" increments). I thought it wouldn't but this operation really took it out of me.
Attachments
336 Machining.jpg
337 Machining.jpg
338 And Finally a Roughed Out Brake Shoe Blank.jpg

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