Author Topic: Plans for L C Mason cam lobe milling fixture  (Read 614 times)

Offline charley lei

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Plans for L C Mason cam lobe milling fixture
« on: January 10, 2022, 01:31:17 AM »
Hi I am working on Bob shores silver bullet engine, and was going to use the cam fixture in his drawings. I run across the fixture  L C Mason built. I can figure out most of the fixture. I was wondering if the plans where available, where to get them and cost. Thanks CHARLEY

Offline kuhncw

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Re: Plans for L C Mason cam lobe milling fixture
« Reply #1 on: January 10, 2022, 05:54:21 PM »
Hi Charley,

When I built my Silver Bullet I used the cam turning fixture shown in the drawings.  This offset turning method has been around for some time and has been written up in various places.  Steve Huck wrote a very good article on the method which was published the Model Engine News website.

http://modelenginenews.org/techniques/hucks_cams.html#t7

You mentioned a fixture by L C Mason.  Are you referring to Mason's process for turning individual cam lobes then arranging them on a shaft?  He explains this in his book, Building Mastiff".  Perhaps others know of additional sources for Mason's process.

The fixture in the Silver Bullet drawings works well and eliminates the need to orient and Loctite individual cam lobes.

Chuck

Offline charley lei

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Re: Plans for L C Mason cam lobe milling fixture
« Reply #2 on: January 11, 2022, 01:07:42 AM »
Thank you very much, I will get the mastiff building book. I started making a cam grinding machine, till I see the individual lobe machining procedure. If i keyed them on a shaft, with spacers and pin the end spacer plus loctite should  be strong. Thanks again.   Charley

Offline kuhncw

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Re: Plans for L C Mason cam lobe milling fixture
« Reply #3 on: January 11, 2022, 02:49:19 AM »
Charley,

The bad news is that Mason's book is out of print and used issues are listed for crazy money.  Hemmingway Kits sell drawings and construction notes for the Mastiff which may include details for making the cam lobes.  Perhaps someone else on the forum knows for sure.

Quite a bit has been posted on the forums about making cams  and cams with individual lobes.  Some make lobes in the mill with a rotary table and boring head. 

The fixture and method in the Silver Bullet plans works well and eliminates the need to orient and lock individual lobes to a shaft.

Chuck

Offline Jo

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Re: Plans for L C Mason cam lobe milling fixture
« Reply #4 on: January 11, 2022, 11:50:14 AM »
The drawings for the jigs are on the Mastiff drawings. I am not sure which one you are meaning.

The cam lobes were machined using an eccentric jig with the required angles marked on the edge - same as I have used on various twin eccentric engines like my Stuart 5A. You mount the blank cam on the mounted eccentric with a line pointing at the first angle marker, machine it, the rotate the blank so the line points at the other and machine it.

The assembly jig is nothing more than a clamp to hold the cam shaft vertically, two bars and a plate with the required angles on it. As you slide each cam into place you point it at the required angle and let the loctite set.

Jo
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