Author Topic: 3.5" Northumbrian Loco  (Read 2152 times)

Offline Baner

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  • Cowaramup, Western Australia
Re: 3.5" Northumbrian Loco
« Reply #30 on: August 26, 2018, 01:28:13 PM »
There's not much to add I'm afraid. I've been busy, just not with loco parts. :( There's been a bit of shop re-organizing, work on another project, house and garden work, and preparing for a new baby due on Sept 4th...
All that's been done is slotting the eccentric straps for the rods:

Northumbrian by DAVID BANER, on Flickr

And cutting out some blanks for the rods themselves:

Northumbrian by DAVID BANER, on Flickr

I need to print out a drawing of the rod profile to glue onto the blanks to use as a shaping guide. Trouble is I don't have a printer at the moment, so I need to get to the local library and print there.
When I find the time...

Dave.

Offline zeeprogrammer

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Re: 3.5" Northumbrian Loco
« Reply #31 on: August 26, 2018, 03:15:00 PM »
Progress is progress.  :ThumbsUp:

And congrats on the upcoming event!
Carl (aka Zee) Will sometimes respond to 'hey' but never 'hey you'.
"To work. To work."
Zee-Another Thread Trasher.

Offline Baner

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  • Cowaramup, Western Australia
Re: 3.5" Northumbrian Loco
« Reply #32 on: August 27, 2018, 12:16:04 AM »
Thanks Zee :)

Offline Baner

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Re: 3.5" Northumbrian Loco
« Reply #33 on: September 01, 2018, 02:02:29 PM »
Alright, some progress!
I'd needed to profile the eccentric rods and my normal practice would be to print out a drawing to scale, glue it to a blank and have at with a file. Unfortunately my printer had long since died and I'd not been motivated to replace it. Turns out eccentric rods are the right sort of motivation:

Northumbrian by DAVID BANER, on Flickr

And after some drilling and filing:

Northumbrian by DAVID BANER, on Flickr

These fit in the slot previously machined in the eccentric strap. Whilst the cutter used was 2mm, and material used was 2mm, the fit was quite loose. This is an easy fix with shim stock. I keep a selection of sizes on hand for just this occasion. A small piece was cut and super glued to the rod (for convenience of handling):

Northumbrian by DAVID BANER, on Flickr

The pump eccentric strap was drilled:

Northumbrian by DAVID BANER, on Flickr

And finished by riveting the rod to the strap. The other eccentric straps will stay loose for now until more of the valve gear is made, in case any adjustments need to be made for fitting. I also managed to put some dings in the strap with the rivet snaps. I'll need to come up with some new snaps that give a little more clearance.

Northumbrian by DAVID BANER, on Flickr

Dave.