Reconditioning a valve seat in an old steam whistle

I just picked up the following steam whistle the problem is it is missing the valve which is essentially a poppet that sits at the bottom of it and seats on the angled surface shown below. The seats didn't look to be in the best condition and they seem to have somewhat of a radius on them. Rather than try to reverse what's there and try to machine it into the new poppet I am wondering if now may be a good time to recut the seat and start with something known so that I can cut a new valve with seat to fit it. I am thinking ideally just go with 45 deg then finish lap in place the new valve? Or is this nor a good idea for a steam valve?

I am not in the shop right now but the OD I believe is 2"pipe thread for an idea of size.

What's the best way of doing this? Ebay is loaded with valve cutter kits but I only need one size and to use it once on cast bronze. HSS should work fine here. Where's the best place to buy them? I did a quick search of Mcmaster and MSC but didn't see them but perhaps I am searching wrong?

Then next thing do you just machine up a bushing to fit the ID and turn it by hand or how are valve seat cutters typically used? Fixturing this thing in on the mill or lathe seems out of the question so I am thinking I need something to hold onto the ID. How tight should the clearances be on such a bushing set to avoid chatter? Anyone have any advice for someone whose never done this before?

Thanks

Adam



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View attachment 322472View attachment 322473

Link is no good. If the big diameter of the chamfer is say 2", what size is the thru hole? That might give us a clue on what your options are.

From the description I can’t visualise the valve, however steam services were common in work, even if the seat looks crappy it should make no ( with obvious limitations) difference as the valve gets lapped into the seat with cutting or grinding paste, run it till there’s a bright ring showing, steam is notoriously capable of eating the valve seat so it’s a regular thing, it’s amazing how quickly steam valves start leaking.
There is a proprietary valve compound I beleive in the US, we used ordinary valve grinding paste and cleaned it out with a rag and solvent, there’s the right brass or bronze too, it’s DZP or dezincification resistant stuff
Your McMaster might help, we don’t have that over here, I hada few sticks of centrifugally cast alpha bronze but threw it into the scrap bin when the price was more than I paid, I now regret that!
I’m guessing your going with air so you don’t need that amount of fussy
Mark

boslab said:

From the description I can’t visualise the valve, however steam services were common in work, even if the seat looks crappy it should make no ( with obvious limitations) difference as the valve gets lapped into the seat with cutting or grinding paste, run it till there’s a bright ring showing, steam is notoriously capable of eating the valve seat so it’s a regular thing, it’s amazing how quickly steam valves start leaking.
There is a proprietary valve compound I beleive in the US, we used ordinary valve grinding paste and cleaned it out with a rag and solvent, there’s the right brass or bronze too, it’s DZP or dezincification resistant stuff
Your McMaster might help, we don’t have that over here, I hada few sticks of centrifugally cast alpha bronze but threw it into the scrap bin when the price was more than I paid, I now regret that!
I’m guessing your going with air so you don’t need that amount of fussy
Mark

Click to expand...

Bob,

Here's a picture of the cross section of a typical whistle. The poppet seat is right where the #3 is called out. As for blowing it, we have a steam show with a few big boilers here so I would like to hear it on steam at some point. I may also run it on air but I am going to need a lot of that. You can see the shop stool it's sitting on for a sense of scale. I will need to get dimensions later on the actual ID but I am pretty sure we're looking at 2"NPT being the od of the valve seat.


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Here is another design
Steam whistle - Wikipedia

Since it's just for occasional use, I'd probably just lap my new valve to the existing seat and call it done.

You're not asking it to hold back high pressure steam 24-7-365 or blowing it at every station and level crossing.

crazygoat said:

Link is no good. If the big diameter of the chamfer is say 2", what size is the thru hole? That might give us a clue on what your options are.

Click to expand...

This is odd, when I looked at the photo on my phone the images show up just right. But on a web browser they don't. Try these;


It is definitely a vertical poppet and not the style valve that Michigan buck posted.

I don't have dimensions right now as the whole thing is sitting in some penetrating oil but could get later if needed.