Marks Holt 75

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G'day Mark, et al.

Good to know your back in the shop. Any big celebrations mid last month ?????

Noticed in post #155, you've used shoulder bolts for the rocker pins, very cluey.

Attached are some pix of the shoulder bolts I'm using for a steam loco crosshead rebuild. These are Dia 6 by M5 by 25 long. I needed fitted bolts so modified some shoulder bolt to suit the need. Might add some more bling to the heads on your Holt.
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Ironically, the buff coloured envelope these are sitting on contains the Holt 75 drawings from George.
 
Attached are some pix of the shoulder bolts I'm using for a steam loco crosshead rebuild. These are Dia 6 by M5 by 25 long. I needed fitted bolts so modified some shoulder bolt to suit the need. Might add some more bling to the heads on your Holt.

Yes, I like that. And I will be doing as you suggest. I looks like you used a cutter with a slight radius. I will need to order a cutter like that or modify something I have.

Any big celebrations mid last month ?????


I can't recall anything going on in mid May unless your referring to my turning 70. This is my favorite card, it captures me perfectly.

card.jpg
 
G'day Mark.

Yes. I used a 6mm carbide cutter with a .5 rad. (Good eyes Mate) Clocked up the collet holder on centre, used the X axis both + & - (climb mill) and rotated the collet holder twice for all six sides. Head dia is 10mm, hex is 8mm AF. X+7 then X-7 on return. One pass. Very quick and easy. Prob 1 minute each.

Yes. 70th. Love the card …..


Regards,

Trevor,
Melbourne, AU.
 
With the machine work completed on the manifolds its time to put a finish on them. I started with nickle plating them The sandblasted surface gives a satin look to the plating but it's to bright. To fix that I dipped the manifolds in a gun bluing solution. The exhaust manifold I left in the dip a little longer than the intake, and then heated the manifold with a torch to give it somewhat of used look.

I have been working on the radiator core. Will post a few photos latter this week.

Mark T


manifold end.jpg


Manifolds all mounted.jpg
 
Time to make a radiator. Starting with the tubes for the core. Having waited far too long for the half inch square stock to be shipped and delivered I decided to use hex stock instead. I only had an almost 36” length so I had to make them .2” shorter than the plan calls for. I will make up the difference with the lower tank. To make setting up for the cuts easy I opted for .1” spacing, .045” cut, .065” thick fin. I drilled the hole through the part after turning the fins. Still needs to be cleaned up but that will have to wait until the tanks are soldered on.

Mark T
Holt core tube.jpg

holt core 2.jpg

holt core1.jpg
 
That radiator is wonderful with hex!!
How about putting this engine on a lawnmower? I remember a pictures of a lawnmower with an Stuart Turner steam engine on it, the builder said he never had any problem getting the grandchildren to cut the grass for him!
Anyone else remember that? I cannot find anything about it now?
 
I would like to thank those that left comments on my last post. A appreciate it.
Mark T


The radiator tanks are easy to make parts. I made one change in that the radiator vent is drilled into the body of the top tank. The plan called for the vent to be a tube along the top of the tank on one side. I was able to cut the letters using my cnc router. The cutter was only .063 on diameter so the 10,000 rpm spindle was not a problem. After soldering the tanks to the core I checked for leaks and then clamped it up on the mill to square the sides. I had left about .010” of material for that on each side. I like to work with brass but I hate the look of bright brass. A few seconds in a brass aging solution darkens it up. I will probably take a bit of fine steel wool and give it some highlights before I'm done. The last photo make it look like the letters are painted white, they are actually polished brass.

Mark T

Holt Radiator tank parts.jpg


holt Radiator assembly.jpg


Holt Radiator trueing.jpg


holt Radiator blasted.jpg


holt Radiator.jpg
 
The radiator is completed and mounted. I deviated from the plan with the mount and the fan shroud. The plan called for a number of parts made from aluminum. I have a good supply of brass scraps accumulated from years as a boat builder. So I made a simpler mount and shroud from brass soldered together as a single part.

Summer is here so I plan to sit in the sun and sip whiskey while I watch the deer eat my roses. Bound to cut into my shop time some. I think I will be making the water pump and water lines next.

Mark T

radiator mount and fan shroud.jpg

Radiator rear.jpg


Radiator side.jpg


Radiator front.jpg
 
Looking beautiful!

Summer is here so I plan to sit in the sun and sip whiskey while I watch the deer eat my roses. Bound to cut into my shop time some.

I'm in Florida and it's exactly the opposite. Time to lock myself indoors and spend more time in the shop. All the critters around here, deer, turkey, hogs, all the fish, whatever, are more active at night. Winter's our season for getting outdoors.
 
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