Looking for a pair of Short Arms for a Type 4 No. 45 Stanley Combo Plane

Those rods are 3/8" in diameter.  If you're just after function, a pair of 3/8" bolts from your hardware store, with the threaded part and the head cut off, will do the job.  A little filing on the cut ends will smooth off the swarf from the cut.

Bolts like that commonly come in Grade 5 and Grade 8.  I'd lean toward Grade 8 bolts, because they'll likely be smoother and certainly stiffer, with a harder surface (less likely to get divots from the clamping screws).  But look at them in the store and decide.  Cutting off the parts you don't need on two Grade 8 bolts may wear out a hacksaw blade, but that's not a big cost.

Bill
Thanks for reply but you're losing me here.
Don't the short rods need to have threads to use them.
I have some taps and dies but I'm told Stanley used odd
threading specs. In any event, I was hoping to find correct
factory parts to go in the wood box I cobbled together.

Hello, Mike. Nice job on the box!! Try   Michael Jenks   justplanefun.   If you have trouble reaching him, send me a pm. Regards, Lou

Mike, Here's another place. Eric's a good guy.

https://nhplaneparts.com/

Mike

Hello, Mike. I second your recommendation, I have bought from Eric before, he knows his stuff! Regards, Lou

I have 30 totes of plane parts and parts planes that I have not cleaned and sorted yet.  I will try to dig around some this weekend and see if I have any.

Thanks for all input
I have been in contact with Eric at NHplaneparts.com
He is pulling the short rods; he spent a good deal of time talking
with me about what is a small order. Seems very knowledgeable
May have to look into some hollows and rounds for the 45 from him.

Forgive me; I'd never seen an early model, and didn't realize the rods thread in.  On both of the 45 bodies I have, the rods are retained by set screws.