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Nusky/Mercer 0-4-0 driver width?

Posted: Sun Jul 07, 2019 3:51 pm
by Sandiapaul
Hi all,

I'm building a 0-4-0 camelback. The drawing for the drivers shows 2 different dimension for the tire width, depending on gauge. For 7.25(which is what I am building) shows an overall width of .875". For 7.5 gauge it shows the IBLS recc width of .750".
Anyone know why its like this? Only thing I can think of is it would allow so extra room to run the 7.25 version on 7.5 track.

Thanks,
Paul

Re: Nusky/Mercer 0-4-0 driver width?

Posted: Sun Jul 07, 2019 5:14 pm
by ChipsAhoy
Is the narrower driver on the wider guage to help prevent having to move side rods, valve gear or perhaps cylinder outboard? Or in other words having a narrower driver causes the flanges to be further apart by default.
Scotty

Re: Nusky/Mercer 0-4-0 driver width?

Posted: Sun Jul 07, 2019 6:24 pm
by GO&PRR
Hi Paul,

Looking at the two drive wheel views, the top one is for the 7-1/4" gauge version which has the wider tread at 11/16" and a flat back.

Comparing to the next drive wheel view for the 7-1/2" gauge version, has a 9/16" tread. NOTE that this wheel has a 1/8 boss on the backside. This simply moves the flange out for the wider 7-1/2" gauge. Thus the axles can be made the same for both gauges for that design.

In my opinion, I prefer the wider treads also for the 7-1/2" versions. To do that, turn the wheels like the 7-1/4" drawing and then lengthen the axles by 1/8" on each end, keeping the 1" length thru the wheel. The 'revised' cylinder castings (Mercer now offered by IHS) offer more meat at the mounting face so that they can be machined with the extra 1/8" distance. Older builds may have used a 1/8" spacer. A thrust washer can be introduced between the drive wheel and the journal box.

Hope this helps.

Re: Nusky/Mercer 0-4-0 driver width?

Posted: Sun Jul 07, 2019 7:47 pm
by Sandiapaul
Thanks for the info Ed. I'm almost ready to make the drivers so this is good info.

Re: Nusky/Mercer 0-4-0 driver width?

Posted: Sun Jul 07, 2019 9:14 pm
by JohnHudak
GO&PRR wrote:
Sun Jul 07, 2019 6:24 pm
(Mercer now offered by IHS)
Hope this helps.
Ed, does IHS have a website?

Re: Nusky/Mercer 0-4-0 driver width?

Posted: Mon Jul 08, 2019 8:46 am
by PRR5406
Hooray! Another A5a joins the fleet!

Re: Nusky/Mercer 0-4-0 driver width?

Posted: Mon Jul 08, 2019 6:02 pm
by Fender
Watch the clearance between the crosshead and the crankpin on the lead driver. Pretty close clearance there.

Re: Nusky/Mercer 0-4-0 driver width?

Posted: Mon Jul 08, 2019 6:46 pm
by GO&PRR
Hi John,
Do not have a web site yet but is on the list to do's.
Send a note to ihsc775@gmail.com and can reply with a price list showing what is currently available on the A5a.

Re: Nusky/Mercer 0-4-0 driver width?

Posted: Mon Jul 08, 2019 7:01 pm
by Sandiapaul
Thanks for all the responses guys!