Author Topic: Stuart Hammer odd shaped hole  (Read 1848 times)

Offline kev

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Stuart Hammer odd shaped hole
« on: December 23, 2015, 04:59:24 PM »
How on earth do I machine a centre hole this shape other than making a broach I cant think of a way but it must have been done a thousands of times and more



Online Jasonb

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Re: Stuart Hammer odd shaped hole
« Reply #1 on: December 23, 2015, 05:06:08 PM »
File :)

Whats the material as a broach is not hard to make and may not even need hardening depending on what it has to cut.

Offline kev

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Re: Stuart Hammer odd shaped hole
« Reply #2 on: December 23, 2015, 06:31:06 PM »
there are two parts with this hole, one is gun metal and the other cast iron. A piston rod moves is the same shape and its just to stop it rotating so maybe a file would be enough :)

Online Dan Rowe

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Re: Stuart Hammer odd shaped hole
« Reply #3 on: December 23, 2015, 06:47:10 PM »
I used a file to do it, but I somehow made the flats on the cast iron section on the wrong side. I had to modify the return trip lever to fit the shaft now turned 900.

Dan
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Offline derekwarner

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Re: Stuart Hammer odd shaped hole
« Reply #4 on: December 23, 2015, 10:43:06 PM »
Kev......following is an image of a model Stuart steam hammer. :hammerbash:...... is this the part in question?....

If so this builder appears to have the flats on the rod at 90 degrees to the Drawing

If you could manufacture a round broach, then machining it back to a 1/2 round profile [+ reduced width] ....assembling the components & broaching both passes in both components would be the obvious procedure

The 77733 x 7/16" image in 'special shape' format is what I was trying to explain......

Clearly the design is to achieve an anti rotation of the hammer head....so if the equivalent flat surface are is provided by one larger flat over two shorter flats could be worth considering

Certainly a high wearing component assembly  :wallbang:

Derek
« Last Edit: December 23, 2015, 10:56:26 PM by derekwarner_decoy »
Derek Warner - Honorary Secretary [Retired]
Illawarra Live Steamers Co-op - Australia
www.ils.org.au

Online Dan Rowe

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Re: Stuart Hammer odd shaped hole
« Reply #5 on: December 23, 2015, 10:57:53 PM »
Cool now I see I am not the only guy who made that part wrong..... I see that the builder did not make the lever longer to ride near the flat as I did to cover my goof.

Dan
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Offline kev

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Re: Stuart Hammer odd shaped hole
« Reply #6 on: December 23, 2015, 11:15:15 PM »
yes thats the part. I have been studying it more and i dont think the accuracy is so critical now as there is a large cavity that you stuff with graphite yarn so im thinking to try a simple file once the two parts are together

Online Dan Rowe

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Re: Stuart Hammer odd shaped hole
« Reply #7 on: December 24, 2015, 01:33:59 AM »
I ground flats on a round file intended for a die filling machine. I now years later have a die filer so it would be a simple and quick operation.

Dan
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Online Jasonb

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Re: Stuart Hammer odd shaped hole
« Reply #8 on: December 24, 2015, 08:25:37 AM »
A broach similar to teh one I made in teh following thread may do it, just put two flats on and harden for teh iron casting

http://www.modelenginemaker.com/index.php/topic,5248.msg103906.html#msg103906

Offline kev

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Re: Stuart Hammer odd shaped hole
« Reply #9 on: December 24, 2015, 08:47:21 AM »
thanks guys, I think I will try the broach first its only going from 7/16 out to 1/2 inch so there is not a lot of metal to remove