Author Topic: A tiny 3 Cylinder Holt based engine  (Read 26530 times)

Offline PJPickard

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Re: A tiny 3 Cylinder Holt based engine
« Reply #150 on: February 03, 2018, 10:28:32 PM »
A favorite engine of mine and a fantastic job on it!

Offline kuhncw

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Re: A tiny 3 Cylinder Holt based engine
« Reply #151 on: February 04, 2018, 12:05:39 AM »
Very nicely done, George!

Chuck

Offline 90LX_Notch

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Re: A tiny 3 Cylinder Holt based engine
« Reply #152 on: February 04, 2018, 01:15:56 AM »
It really is stunning George.  I wish that I could find a way to get to NAMES just to see it in person. 

-Bob
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My Engine Videos on YouTube-
http://www.youtube.com/user/Notch90usa/videos

Offline michelko

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Re: A tiny 3 Cylinder Holt based engine
« Reply #153 on: April 02, 2018, 08:44:59 AM »
I finished up the components for the distributor. I machined the brackets to give them a little more character. The rotor is complete.
I made the cap and rotor from black Delrin. I have used it in the past with good luck. It machines nice and seems to have good electrical qualities. I turned the cap then mounted it on the end of a fixture rod and set it up in the mill vise, indicating it to achieve true center. The center holes were drilled .062 followed by a .104 dia. drill for the plug wires. I then used my home-made coring tool to cut the terminal posts. The cutter was drilled out to the size of the terminals then bored to add 3 degrees of back draft to allow for clearance while it was cutting. The cutter was then fluted, hardened and the cutting edges honed with a diamond tool. The cap is held in place with 2 0-80 screws.

Hi george,
Very nice bulid. Couldyou say something about how the leads are mounted into the cap? Maybee show a inside photo of the cap?Would like to see the rotor too.

Regards Michael

Offline gbritnell

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Re: A tiny 3 Cylinder Holt based engine
« Reply #154 on: April 02, 2018, 01:17:18 PM »
Hi Michael,
 Here's how I do the wired and cap.
 The cap is turned from a piece of Delrin. I counterbore the inside out to the proper depth and cut it off. I make what's know in the wood world as a plug cutter from drill rod.
This is used to form the terminal posts on the top of the cap. The cap is now mounted in a holding device in my mill and centered. I drill through at each of the terminal locations with a 1/6th drill for brass rivets. This is followed with a #38 drill (.101) I also have another #38 drill that I have the tip ground flat to act as a counterbore to flatten the bottom of each hole.
 The wire I use comes from S&S Machine Tool. They make the miniature ignition components. The wire is .099-.100 diameter so it's a nice fit in the hole.
 I then use my plug cutter to form the outside of the terminals. While I'm doing this I also make a terminal post on a scrap piece of Delrin. (Explanation to follow)
 I make up little brass rivets that are drilled through. This allows them to be 'riveted' in place in the cap.
 I now take the extra terminal post that I machined and start forming the wire ends that go in the cap. I make up tiny brass discs about .095 diameter with a through hole that the wire will go through. I strip a small amount of wire and pass it through the disc. I then spread the wire out in a fan shape which holds the disc in place. I then touch it with a small soldering iron to solder it in place.
The wire is now inserted into the cap and a piece of shrink tubing is slid over the wire and up against the distributor terminal. This acts as a bushing so that the outer piece of shrink tubing won't have to shrink down as far. I then cut the outer piece of shrink tubing. This is long enough to go over the terminal and over the bushing piece. I then heat shrink it in place. I do this on the spare piece I made because if you try to shrink it on the cap you will start melting the adjacent terminals.
 Once the shrink tubing is cool I pull it off the fixture plug and press it into the actual cap. Usually the shrink tubing has formed a nice tight fit so between the fit of the wire in the hole and the outer tubing it holds the wires in place quite securely. If one of them seems a little loose I put a very tiny dab of black silicon sealer on the outside of the terminal and slide the wire assembly down over it. Once the silicone had dried it holds the wire tight but can be pulled off if necessary.
 
Talent unshared is talent wasted.

Offline Craig DeShong

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Re: A tiny 3 Cylinder Holt based engine
« Reply #155 on: April 03, 2018, 10:35:01 PM »
Words fail me George, absolutely stunning.  Work at this level makes me realize how much I yet need to learn.
Craig

Offline michelko

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Re: A tiny 3 Cylinder Holt based engine
« Reply #156 on: April 04, 2018, 06:41:32 AM »
George,
many thanks for the detailed description.
Michael