James Coombes

[Steve WithnellParticipant @stevewithnell34426]

After too many years languishing under the bench, I finally pulled out my James Coombes build.

I had intended to build "to plan", unlike my Victoria, which I made substantial modifications to.

I was pleased to find I'd made much more progress than I remembered, but I hadn't stuck to plan! I'd never liked the table columns, it didn't seem right to transition the round columns to a square platform. Just me being a bit OCD, so I turned them from square bar, so I could create a square plinth top and bottom. I'm pleased with how they look, but it has created a fitting problem – the valve gear bearing blocks screw directly on to the threaded posts that secure the columns. Any misalignment in the thread axis is corrected by rotating the column.

I need to fix that first, before I progress.

Any ideas welcome!

Steve

[Steve WithnellParticipant @stevewithnell34426]

[JasonBModerator @jasonb]

If you know the pitch of the thread then leave the posts long and screw them into position, work out how much more they need to rotate to line up and then divide the pitch by that amount / 360 and machine that amount off the bottom of the post.

Alternative is to turn off teh square capital and base and make them as separate pieces

Edited By JasonB on 24/04/2021 13:14:31

[Jim NicParticipant @jimnic]

+1 for turning off the square capital and using separate pieces which are free to turn on the longer threaded portion of the column. That is what I did on my first table engine, not a James Coombes but a Stew Hart. I actually drilled and tapped the columns to take studs to save making all new columns.

Jim

[Wayne JepsonParticipant @waynejepson32122]

Did you make the con rods yet? I read all your original”with chips” posts and find them very useful. Just starting a James Coombes build myself. Thanks

[JasonBModerator @jasonb]

Coming back to the original question, if you have not got over it by now than moving the supports to another position is also an option and one that I have gone for on my much modified JC.

I'll be doing my conrods in the next week or two if you have any questions Wayne, the short one and the yoke were completed last weekend I'm not soldering as per the Stuart design but bolting together.

[Wayne JepsonParticipant @waynejepson32122]

Looks great thanks, please keep posting your progress because I’m going to closely follow your build while doing mine. I think your toke looks much better than the original design.

wayne

[JasonBModerator @jasonb]

Wayne, I tend to do most of my posts about an engine once it is finished with just the odd progress shot during the build. But if it helps the photos are being added to this album and feel free to ask about anything. Although I have used my CNC for a few bits it could all be done with manual machines with a few slight alterations, from the look of your No9 you should have no trouble with a JC.

Probably best to start your own build thread on here.

PS the album will default to newest first so either change that or start at the end and look backwards so images are in order.

Edited By JasonB on 04/12/2022 07:29:04

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