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Holt drawings

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Project of the Month Winner!!!
Project of the Month Winner
Jul 16, 2007
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There had been discussions regarding the availability of Holt casting and particularly the drawings. Due to the copyright nature of the original drawings many people weren't comfortable copying or selling their drawings.
In one of the threads someone had asked about my scratch built Holt and whether I had drawings for it. I replied that I would commence making the drawings from my own engine and might have them available in the fall. What with the wet weather we've had I have spent more time at the computer and have completed a set of drawing for my Holt.
I have added or modified a lot of the details from the original to improve the things that I have found in building and running my engine.

Here is a list of the changes.
1. The crankcase is made from 2 pieces split at the main bearing centerline.
2. The main bearing pockets in the crankcase are rectangular so that the block doesn't need to be line bored for
the crankshaft.
3. The end main bearings housings are one piece utilizing round bearing inserts.
4. The front and rear main bearing housings can now be machined for O ring seals.
5. The front main bearing housing is enlarged providing a better surface to mount the timing gear box.
6. The ignition point timer lever and design have been changed to use a Hall trigger.
7. The intake and exhaust manifolds are drawn so that they can be fabricated and still retain somewhat of the original shape.
8. The carburetor is changed to utilize the one I have found works the best.
9. The coolant lines and fitting have been enlarged from .156 I.D. to .187 I.D. for better cooling
10. There are drawings for the water pump which was never included with the original.
11. The drawing set includes drawings for the fan assembly, radiator and fan shroud that I use on mine.
12. There are drawings for an engine mounted fuel tank with the brackets.
13. There is a drawing to utilize a one way bearing for starting but doesn't modify the large flywheel if the user want's to start the engine by some other means.
14. There is a drawing for a skid to mount the engine too.
15. The governor has been redesigned with all the proper linkage to actually control the carburetor.

The drawings are done in Autocad like all my other drawings and are done one 8-1/2 x 11 sheets so they can be printed out at home. The are supplied as PDF files.
I'm sorry for the Metric people but the dimensions are all done in Imperial.
The set of drawings is 32 sheets and is available for $65.00 through Paypal or by check.
You can contact me at: [email protected] if you are interested.


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Well-Known Member
Jan 2, 2013
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George, Great Job!! I assume you found answers to the questions you had for me.
I think it's great to give something to the hobby. I hope there are some who will build this wonderful engine.

I have wanted to do this with the Gothic Steam engine scaled from the one at the Henry Ford Museum. I have put this engine into Solidworks and have made many improvements and corrections over the original version from Historic Model Designs. The thing is I wanted to post it for free to a board, but there over 130 pages. If anyone is interested you may contact me at [email protected]. Since I own this design, there won't be any copyright infingements.

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