Author Topic: CONWAY 0-4-0 3 1/2" GAUGE LOCO  (Read 23793 times)

Offline Firebird

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Re: CONWAY 0-4-0 3 1/2" GAUGE LOCO
« Reply #315 on: December 24, 2017, 04:27:34 PM »
Hi

I have purchased the 5 eccentric straps as gun metal castings. Having had the experience of the (poorly made) hornblocks the first job was to measure them all over. There is enough material on each but not much to spare.

I have cleaned up one face on the disc sander and filed away any bits of casting around the edges.



I'm not sure as yet as to why the axle pump strap has smaller bolts than the other 4. I intend to use stainless steel cap heads and locknuts on the final assembly so 3mm and 4mm will be used



Each strap is number punched top and bottom. No. 5 will be used for the axle pump strap and have smaller bolts



Each strap has its bolt holes drilled indexing off the cleaned up face



In the mill the straps are seperated with a slitting saw



Then bolted together



Cheers

Rich

Offline Firebird

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Re: CONWAY 0-4-0 3 1/2" GAUGE LOCO
« Reply #316 on: December 28, 2017, 05:17:16 PM »
Hi

Each eccentric has its mating faces skimmed



Back to the boiler now. I have knocked up a one way valve for the test rig. I'm noticing a very slight pressure drop on the gauge so I need to eliminate the pump.





A slight mod to the pipe work



Cheers

Rich

Offline Firebird

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Re: CONWAY 0-4-0 3 1/2" GAUGE LOCO
« Reply #317 on: December 28, 2017, 07:41:47 PM »
Hi

By George I think I've got it  :cartwheel:  :wine1:  :cheers:  :DrinkPint:  :ThumbsUp:  :whoohoo:

The pressure held at 100 psi for 20 minutes


Cheers

Rich

Offline crueby

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Re: CONWAY 0-4-0 3 1/2" GAUGE LOCO
« Reply #318 on: December 28, 2017, 08:22:26 PM »
 :cheers:    :agree:    :)    :D    :drinking-41:

Offline Kim

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Re: CONWAY 0-4-0 3 1/2" GAUGE LOCO
« Reply #319 on: December 28, 2017, 10:32:38 PM »
Congratulations, Rich! Well done!
Kim

Offline 10KPete

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Re: CONWAY 0-4-0 3 1/2" GAUGE LOCO
« Reply #320 on: December 28, 2017, 10:38:09 PM »
Congratulations!!!

 :cartwheel:

Pete
Craftsman, Tinkerer, Curious Person.
Retired, finally!
SB 10K lathe, Benchmaster mill. And stuff.

Offline Jo

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Re: CONWAY 0-4-0 3 1/2" GAUGE LOCO
« Reply #321 on: December 29, 2017, 08:25:23 AM »
Well done Rich  :ThumbsUp:

Jo
Usus est optimum magister

Offline Firebird

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Re: CONWAY 0-4-0 3 1/2" GAUGE LOCO
« Reply #322 on: December 29, 2017, 05:52:48 PM »
Hi

Thanks Crueby, Pete Kim and Jo  :ThumbsUp:

The eccentric straps need to be bored. 2 ways of doing this , in the lathe in a 4 jaw chuck or on the mill. I opted for the mill as I have a powered Z axis. The straps are mounted on top of the vise, with an angle plate at the left hand end to make mounting all 5 straps easier.

Heres a bit of video showing the boring operation


I made a gauge for checking the bore size





The same gauge was then remachined to machine the straps to width



A trial fit




Cheers

Rich
« Last Edit: December 29, 2017, 07:06:33 PM by Firebird »

Online b.lindsey

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Re: CONWAY 0-4-0 3 1/2" GAUGE LOCO
« Reply #323 on: December 29, 2017, 11:23:09 PM »
Nice work Rich, and congrats on the boiler hydro test as well.

Bill
« Last Edit: January 06, 2018, 10:10:03 PM by b.lindsey »

Offline Firebird

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Re: CONWAY 0-4-0 3 1/2" GAUGE LOCO
« Reply #324 on: January 05, 2018, 11:23:32 AM »
Hi

Thanks Bill  :ThumbsUp:

To finish the eccentric straps a 1/8" slot is cut with a slitting saw




Cheers

Rich

Offline Firebird

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Re: CONWAY 0-4-0 3 1/2" GAUGE LOCO
« Reply #325 on: January 06, 2018, 08:48:30 PM »
Hi

The plans call for the eccentric rods to be machined from 3/4" x 1/2" steel.



Only the fork end is 7/16" the rest has to be machined down to 1/8", a lot of waste. Also the fork end has to be case hardened. I have some of the modern case hardening powder which doesn't work as well as the good old fashioned stuff  :shrug:

I don't have any steel bar that size but I do have some 3/4" x 1/8" so I decided to have a go at fabricating them. I have used silver steel for the fork ends, I figure silver soldering them to the rods will harden them at the same time.

4 fork ends under construction



And finished



Print out the rods and glue to the steel bar (saves a lot of marking out)



No need for great accuracy here just machine them out by eye



A little jig to help hold things straight while I silver solder



Another jig made accurately so that all 4 eccentrics will be exactly  the same length. A bit of ally the same size as the strap and a steel pin exactly 4 3/16" centres



The strap and rod can be assembled on the jig and two 3/32" (2.5mm) holes drilled and fitted with bolts





Cheers

Rich

Offline Jasonb

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Re: CONWAY 0-4-0 3 1/2" GAUGE LOCO
« Reply #326 on: January 06, 2018, 08:54:59 PM »
Silver soldering won't make them hard. To harden the silver steel you need to quench it when it is red hot but that will leave them brittle, you could then try to temper them.

The case only hardens the surface to resist ware but leaves the core in the original state so less brittle and no risk of fracture.

I've not had problems with the newer case hardening powder

The milled slots in your forks look like they will clash with the expansion link, would have been better held vertically and milled across so you have a rectangular bottom to the  opening not half round.
« Last Edit: January 06, 2018, 09:00:05 PM by Jasonb »

Offline Firebird

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Re: CONWAY 0-4-0 3 1/2" GAUGE LOCO
« Reply #327 on: January 11, 2018, 07:42:04 PM »
Hi

Sorry for the delay fellow forum members, something came up and I had to cut my last post short before I could finish
But Jason has spotted some of the issues that I came across, thanks Jason :ThumbsUp:

Firstly a couple of missing photos

A simple jig to hold things square during silver soldering



Then file the bottom of the fork square



Soldering didn't get the fork hot enough to harden it. My little torch came in handy to heat just the end of the fork to red heat without melting the silver solder



Two of the eccentric rods have to bent





A trial fit on a bit of 1/4" steel bar





A bit of tweaking will be needed but not until final assembly

Cheers

Rich

Offline Firebird

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Re: CONWAY 0-4-0 3 1/2" GAUGE LOCO
« Reply #328 on: January 12, 2018, 06:10:13 PM »
Hi

The eccentric rod for the axle pump is just a plain 1/8" but slightly shorter than the others





The eccentric straps all have a little lug that I assume is for an oil cup. I can find no mention of any oil cups on the plans or in the article but I have decided to include them. Drill and tap 3/16" x 40 then drill through 1mm





Tis the season of the nasty rust monster so I have dunked them in the zinc plating kit





Cheers

Rich

Offline Firebird

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Re: CONWAY 0-4-0 3 1/2" GAUGE LOCO
« Reply #329 on: January 13, 2018, 07:12:55 PM »
Hi

Workshop time is going to be a rare commodity over the next 2 or 3 weeks :'( :censored: :rant: so I can't start anything that will take more than an hour or so.

Today I did a bit of simple turning, some crankpins







Every little bit is a bit that has to be made  :Lol:

Cheers

Rich