The Home Machinist!

Time to get chemically aggressive I would submerge the whole thing in pure acetone and hand work the bearings back and forth, periodically putting just a little bit of air into the oil hole until things are flushed out and clean. You can then decide if the bearings are trash and require replacement....

Before using a wedge, I would consider a brass bar down the center where the draw bolt currently resides...assuming you have already backed the bolt out a couple of turns and tapped on the hex with a dead blow hammer already... The bar should be just smaller than the diameter of the hole. Start with...

No

I have a tom thumb vertical boiler, coal fired.

I have on many occasions, while wearing welding gloves, brushed the tubes while the boiler was hot.

Beats dumping the fire and starting over...but the nobody ever accused me of being 'normal'.

Is no a question of speed -> is a question of having something that will be runable. Large diameter wheels create a torque disadvantage that works against you. You will need to put so much pressure into the cylinders to get the wheels to rotate, that you will overcome the available traction and nay ...

You need to consider traction with a small loco and what appears to be oversize wheels for a model .a live steamercwith wheels that size is going to be disappointing in a world where 2-5 mph may well be the limit. Cutting spoke wheels with a round cutter is very challenging because of the tapered si...

Crap shoot, since optimum depends on velocity of draft. I have used what looks like 1 twist per foot and been happy with results. You can always twist it more...but getting it untwisted is a bit of a headache. Suggest you cut twice as many as you need and start slow. Have a set that you can swap out...

You also need to be aware that backlash in a DRO is really a misnomer. Unless you literally have something loose in the scale ..as in the reader head being loose on the table, or the glass scale being able to move, you need to consider resolution of the scale and resolution of the reading unit. Some...

ah...now you are into 'verification of position' on a machine, which is a whole science in itself -> not the least of which is room temperature control.

as CTM asks -> is this a hand cranker, stepper or servo machine?

good to hear on right track...or correct track?

any recommended gauge/thickness?

whatever you have and can cut....and twist....it really maters not...

i would NOT have them sticking OUT of the end of the flues inside the firebox.

yes..

long term stainless will last longer - but to prove a point.....

Half as**d or not, it will help. Some of the original industrial turbolaters were on gas fired vertical boilers, or water heaters. Absolutely no reason they shouldn't work.. The other option is a lot of small tubes in the vertical, which from a heat transfer perspective amounts to the same thing but...