Author Topic: 31/2" Tich  (Read 8112 times)

Offline samc88

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Re: 31/2" Tich
« Reply #60 on: October 03, 2021, 05:23:25 PM »
Good news! I found a drill which was slightly smaller than specified but still suitable for 7Ba clearance so went ahead and drilled them. Bolts are 7BA with 8BA heads which look good I think and give a more scale impression than full size nuts or the countersunk screws LBSC specified. I'm tempted to use studs and nuts rather than bolts though which should look quite good.
 





Online RReid

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Re: 31/2" Tich
« Reply #61 on: October 03, 2021, 08:34:04 PM »
I find studs and nuts to be far more convenient in a steam chest than bolts/screws. The studs act as alignment pins, making partial disassembly, such as removing the top cover for valve adjustment, easier and more convenient. Very nice looking work! :ThumbsUp:
Regards,
Ron

Offline samc88

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Re: 31/2" Tich
« Reply #62 on: October 18, 2021, 09:26:40 PM »
Made a start on the cylinders. Got both of them machined to length, bored and reamed to 11/16". Hopefully I'll get a chance to machine the bolting and port faces in the mill this week. Lovely castings to work with so far, they machine really nicely.









Online crueby

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Re: 31/2" Tich
« Reply #63 on: October 18, 2021, 10:26:04 PM »
Ah, freshly machined bronze, such lovely stuff!


Looking great!


 :popcorn:

Offline samc88

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Re: 31/2" Tich
« Reply #64 on: October 30, 2021, 07:03:47 PM »
First cylinder machined to final size. Second picture shows how I managed to use the bore centre as a datum. I turned a piece of aluminium to be a good fit in the bore and then using a depth gauge allowed me to take off the required amount. It came out quite nicely :)

Then the second cylinder happened, milling away the port face and then a large void appeared. Luckily it's away from the ports so I think I'll get away with using that wonder stuff JB weld. I was originally going to silver solder it until I realised how big the cavity actually was and didn't fancy spending lots of money on silver soldering what is essentially a non critical area of the face.

Next job on these is the ports but think I'll do the cylinder covers and other bits first
 













Offline cnr6400

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Re: 31/2" Tich
« Reply #65 on: October 30, 2021, 11:07:41 PM »
 :ThumbsUp: :ThumbsUp: :ThumbsUp: :popcorn: :popcorn: :popcorn:

Cylinder parts are looking good!

You're going to be doing a large filling today Doctor, with the JB Weld cavity filling. Hope you've got a new toothbrush on hand for the patient! :Lol:

Offline samc88

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Re: 31/2" Tich
« Reply #66 on: November 24, 2021, 08:19:32 PM »
Not done a great deal to this, I'm awaiting a DRO for my mill so I'll finish off the cylinder bits once that's fitted

In the mean time I made up the valve spindles and piston rods today out of some 5/32" silver steel

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Offline samc88

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Re: 31/2" Tich
« Reply #67 on: November 24, 2021, 08:20:03 PM »
Oh also I did fill the cylinder with JB weld and that worked really well, I forgot to picture it

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Offline samc88

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Re: 31/2" Tich
« Reply #68 on: April 15, 2022, 11:20:27 PM »
Time to drag this out of hibernation now the S50 is done.

Before diving into finish the cylinders I thought to get me back into the build I'd start with the buffers. I started with opening out the holes in the beams and tapping 3/8 x 32. To save buying material I already had a length of 1" steel which needs to be taken down to 3/4". Theres other ways of doing this but Im also using this as an excuse to dial in my tailstock properly as Ive not really had the chance lately after using it for taper turning (was just setup again by eye using a blade between 2 centres). At the last cut I got the taper down to 2 thou over a 6" length. Was getting a bit late so will carry on tomorrow trying to get it spot on, still got 70 thou to come off it so plenty to play with to get it set up right.

Offline samc88

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Re: 31/2" Tich
« Reply #69 on: April 16, 2022, 06:00:36 PM »
Buffer work continues with the stocks. The OD of the steel was finished to 3/4" and then sawn to get 4 sections to make the stocks. I made the outer sides first on each, facing off and then machining to diameter 1/2" for a length of 5/8" before drilling all the way through with a 1/8" drill bit then following with a 3/8" drill to open it out for the buffer heads to slide into. This was repeated for all 4 before turning around in the chuck and turning the section to be threaded 3/8" x 32. Seems to fit quite nicely, just got to finish off the other 3 now
 

Offline Kim

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Re: 31/2" Tich
« Reply #70 on: April 16, 2022, 09:35:43 PM »
Nice progress on the buffers, Sam.

Great to see you making some progress on your Tich again.

Kim