Mutual Improvement Classes are in order to pass on and preserve the skills of the parent topic. In true MIC tradition, these pages are designed to make this knowledge and information available to all. Tue, 21 Apr 2026 01:54:50 +0000 Tue, 21 Apr 2026 01:54:50 +0000 National Preservation https://www.national-preservation.com/forums/locomotive-engineering-m-i-c.47/ Tue, 30 Jul 2024 16:27:16 +0000 https://www.national-preservation.com/threads/laser-rust-cleaning.1424082/ https://www.national-preservation.com/threads/laser-rust-cleaning.1424082/ invalid@example.com (Bikermike) Bikermike
]]> 5 Sat, 18 May 2024 21:54:39 +0000 https://www.national-preservation.com/threads/steam-tight-stays.1423851/ https://www.national-preservation.com/threads/steam-tight-stays.1423851/ invalid@example.com (brennan) brennan https://www.bestt.org.uk/_files/ugd/2e4fbf_6d842609711640eb8ac8585e7170648f.pdf)

there is a section on the use of "steam tight" or "blind stays". These were/are used when the boiler cannot be removed from the frames and there is no access to the outer firebox sides.

The process requires special tooling and great patience and skill on the part of the craftsman. I've replaced many stays where access is available on both sides...

Steam Tight Stays]]> 2 Mon, 25 Mar 2024 13:28:20 +0000 https://www.national-preservation.com/threads/leaf-springs-to-coat-or-not-coat.1423650/ https://www.national-preservation.com/threads/leaf-springs-to-coat-or-not-coat.1423650/ invalid@example.com (mcjlf1) mcjlf1
I would be interested in peoples' experiences/recommendations regarding coating of leaf springs (or not).

I guess for the majority of locos with underslung springs, they tend to get covered in oil & crap pretty quickly and are i) not prone to corrosion, and ii) generally not visible. However, for tender springs, which tend to be mounted externally above the axlebox, and are quite prominent and not prone to coating with gunk and other crap, there is a question of whether to...

Leaf springs - to coat or not coat]]> 9 Sun, 24 Jan 2021 17:16:42 +0000 https://www.national-preservation.com/threads/materials.1419123/ https://www.national-preservation.com/threads/materials.1419123/ invalid@example.com (Jordan Leeds) Jordan Leeds 5 Sun, 06 Oct 2019 17:59:16 +0000 https://www.national-preservation.com/threads/identifying-thread-types.1416989/ https://www.national-preservation.com/threads/identifying-thread-types.1416989/ invalid@example.com (Ploughman) Ploughman
I seem to recall the Nut or Bolt head is chamfered in different styles.

Unlike other groups we cannot eliminate all thread types except one as we use all thread types due to the age range and manufacturing location of our vehicle stock.]]> 20 Mon, 25 Mar 2019 18:39:21 +0000 https://www.national-preservation.com/threads/tyre-flange-profiles.1338000/ https://www.national-preservation.com/threads/tyre-flange-profiles.1338000/ invalid@example.com (David Withers) David Withers
I'm looking for a dimensioned drawing or sketch of P1 and P9 tyre profiles so as to specify the blocks correctly and would be grateful if someone could point me in the right direction.]]> 12 Sat, 22 Sep 2018 15:30:24 +0000 https://www.national-preservation.com/threads/bs-2790-1-1969.1231505/ https://www.national-preservation.com/threads/bs-2790-1-1969.1231505/ invalid@example.com (David Humphreys) David Humphreys
Thank you.

David Humphreys
07787 967694]]> 5 Sun, 12 Aug 2018 07:15:40 +0000 https://www.national-preservation.com/threads/machining-tolerences-for-side-rods.1187038/ https://www.national-preservation.com/threads/machining-tolerences-for-side-rods.1187038/ invalid@example.com (Brian M) Brian M
Between crank pins:
4' 5" plus 0.002", minus 0.002"
4' 4-3/4" plus 0.002", minus 0.002"
3' 3" plus 0.027", plus 0.029"

Between crank pin and tongue pin joint:
7" plus 0.001", minus 0.001"
7-1/4" plus 0.001", minus 0.001"

This must have been jig-boring territory, or by using a machine fitted with 'optics'...

Machining Tolerences for Side Rods]]> 12 Fri, 13 Jul 2018 20:36:47 +0000 https://www.national-preservation.com/threads/odd-threads.1023410/ https://www.national-preservation.com/threads/odd-threads.1023410/ invalid@example.com (Dag Bonnedal) Dag Bonnedal Most of our Swedish, German and British built locos are built with Whitworth standard threads, but there are exceptions. And these days, BSW screws are hardly obtainable in Sweden, only UNC....

Odd threads]]> 8 Fri, 04 May 2018 05:06:00 +0000 https://www.national-preservation.com/threads/combination-injectors.1126868/ https://www.national-preservation.com/threads/combination-injectors.1126868/ invalid@example.com (Steve) Steve 4