Keeping Blowdowns In Line

This forum is dedicated to the Live Steam Hobbyist Community.

Moderators: cbrew, Harold_V

User avatar
ChuckHackett-844
Posts: 232
Joined: Wed May 03, 2017 3:54 pm
Location: Tampa, Florida

Keeping Blowdowns In Line

Post by ChuckHackett-844 »

From time to time the blowdowns on my Northern would stick and the blowdown would rotate on its thread in the boiler instead of rotating valve plate.

It's hard to get these things 1) tight, and 2) in the correct orientation for proper relationship with the linkage.

This year I found the solution ... a locking arm ...

I machined mine from 1/8" thick aluminum because it was at hand. Brass or Stainless would be good also since they don't rust. I considered 3D-printed ABS plastic but I was afraid that it would soften in the heat from the firebox sides.
20230205_172452.jpg
20230205_172452.jpg (891.06 KiB) Viewed 1745 times

I affixed the arm with a bolt that was in a convenient location. There is a spacer between it and the firebox side to hold it parallel to the firebox.
20230205_172732.jpg
20230205_172732.jpg (992.61 KiB) Viewed 1745 times

You can see the lock gripping the hex on the back of the blowdown.
20230205_172748.jpg
20230205_172748.jpg (422.44 KiB) Viewed 1745 times

Should work great ... we will see ...
Regards,

Chuck Hackett, UP Northern 844, Mich-Cal Shay #2
Owner, MiniRail Solutions, LLC, RR Signal Systems (http://www.MiniRailSolutions.com)
"By the work, One knows the workman"
User avatar
makinsmoke
Posts: 2260
Joined: Thu Jul 10, 2003 12:56 pm
Location: Texas Hill Country

Re: Keeping Blowdowns In Line

Post by makinsmoke »

That’s pretty slick Chuck!

You are all set up. Run a few off and offer them!
User avatar
ChuckHackett-844
Posts: 232
Joined: Wed May 03, 2017 3:54 pm
Location: Tampa, Florida

Re: Keeping Blowdowns In Line

Post by ChuckHackett-844 »

Each would probably have to be custom since the mounting hole offset and hex angle are probably different.

They are made using a parametric CAD file in Fusion 360 and cut on my Haas MiniMill CNC.

Glad to share the Fusion project - if I can figure out how ...

To make them, either someone would have to send the modified Fusion project back to me (preferred) or I would have to modify the fastener offset distance, angle (in relation to the blowdown hex), and possibly hex size (mine was .5").

I used a hex angle of 0 on both of mine. The right one could have used tweaking on the angle but I didn't think it was worth the effort. They each had different offsets to the mounting bolts (about 0.200").

If they had a 3D printer they could verify dimensions before I cut it in metal on the mill to avoid re-runs.
Regards,

Chuck Hackett, UP Northern 844, Mich-Cal Shay #2
Owner, MiniRail Solutions, LLC, RR Signal Systems (http://www.MiniRailSolutions.com)
"By the work, One knows the workman"
User avatar
NP317
Posts: 4557
Joined: Tue Jun 24, 2014 2:57 pm
Location: Northern Oregon, USA

Re: Keeping Blowdowns In Line

Post by NP317 »

Interesting need, and a logical solution for you.
I've never have the blowdown valves on my locos come loose as you described.
Different attitude/longitude, perhaps...
RussN
User avatar
cbrew
Posts: 3161
Joined: Sat Jan 04, 2003 12:17 pm
Location: Vancouver Wa

Re: Keeping Blowdowns In Line

Post by cbrew »

NP317 wrote: Mon Feb 06, 2023 12:09 pm Interesting need, and a logical solution for you.
I've never have the blowdown valves on my locos come loose as you described.
Different attitude/longitude, perhaps...
RussN
same, but i tend to be heavy handed with tightening pipe tread :)
If it is not live steam. its not worth it.
Odyknuck
Posts: 815
Joined: Mon Aug 08, 2022 4:21 pm
Location: Chardon, Ohio

Re: Keeping Blowdowns In Line

Post by Odyknuck »

You could probably adapt a pair of air tool wrenches to work.
User avatar
Bill Shields
Posts: 10460
Joined: Fri Dec 21, 2007 4:57 am
Location: 39.367, -75.765
Contact:

Re: Keeping Blowdowns In Line

Post by Bill Shields »

Slick ideas to common problems :mrgreen:
Too many things going on to bother listing them.
User avatar
ChuckHackett-844
Posts: 232
Joined: Wed May 03, 2017 3:54 pm
Location: Tampa, Florida

Re: Keeping Blowdowns In Line

Post by ChuckHackett-844 »

Odyknuck wrote: Mon Feb 06, 2023 5:13 pm You could probably adapt a pair of air tool wrenches to work.
What would be the fun in that? I wouldn't be able to justify the Haas CNC to the wife! :lol:
Regards,

Chuck Hackett, UP Northern 844, Mich-Cal Shay #2
Owner, MiniRail Solutions, LLC, RR Signal Systems (http://www.MiniRailSolutions.com)
"By the work, One knows the workman"
User avatar
ChuckHackett-844
Posts: 232
Joined: Wed May 03, 2017 3:54 pm
Location: Tampa, Florida

Re: Keeping Blowdowns In Line

Post by ChuckHackett-844 »

cbrew wrote: Mon Feb 06, 2023 12:47 pm
NP317 wrote: Mon Feb 06, 2023 12:09 pm Interesting need, and a logical solution for you.
I've never have the blowdown valves on my locos come loose as you described.
Different attitude/longitude, perhaps...
RussN
same, but i tend to be heavy handed with tightening pipe tread :)
Chris, .. and these have been in and out many times and each time they loosen a bit. I'm Leary of pushing them another turn - just what I need, snapped off or stripped - another project :(

Wrapping them with Teflon tape takes up the slack but the tape has somewhat of an anti-friction effect so you really need to use a lot of tape to get them tight again.
Regards,

Chuck Hackett, UP Northern 844, Mich-Cal Shay #2
Owner, MiniRail Solutions, LLC, RR Signal Systems (http://www.MiniRailSolutions.com)
"By the work, One knows the workman"
User avatar
cbrew
Posts: 3161
Joined: Sat Jan 04, 2003 12:17 pm
Location: Vancouver Wa

Re: Keeping Blowdowns In Line

Post by cbrew »

ChuckHackett-844 wrote: Mon Feb 06, 2023 6:55 pm
cbrew wrote: Mon Feb 06, 2023 12:47 pm
NP317 wrote: Mon Feb 06, 2023 12:09 pm Interesting need, and a logical solution for you.
I've never have the blowdown valves on my locos come loose as you described.
Different attitude/longitude, perhaps...
RussN
same, but i tend to be heavy handed with tightening pipe tread :)
Chris, .. and these have been in and out many times and each time they loosen a bit. I'm Leary of pushing them another turn - just what I need, snapped off or stripped - another project :(

Wrapping them with Teflon tape takes up the slack but the tape has somewhat of an anti-friction effect so you really need to use a lot of tape to get them tight again.
yeah,,, i hear ya, pretty sure loctite makes a nice pipe thread compound that may help the moving
If it is not live steam. its not worth it.
User avatar
ChuckHackett-844
Posts: 232
Joined: Wed May 03, 2017 3:54 pm
Location: Tampa, Florida

Re: Keeping Blowdowns In Line

Post by ChuckHackett-844 »

cbrew wrote: Mon Feb 06, 2023 7:45 pm yeah,,, i hear ya, pretty sure loctite makes a nice pipe thread compound that may help the moving
... and holds its strength at 250 F ?
Regards,

Chuck Hackett, UP Northern 844, Mich-Cal Shay #2
Owner, MiniRail Solutions, LLC, RR Signal Systems (http://www.MiniRailSolutions.com)
"By the work, One knows the workman"
Odyknuck
Posts: 815
Joined: Mon Aug 08, 2022 4:21 pm
Location: Chardon, Ohio

Re: Keeping Blowdowns In Line

Post by Odyknuck »

ChuckHackett-844 wrote: Mon Feb 06, 2023 6:49 pm
Odyknuck wrote: Mon Feb 06, 2023 5:13 pm You could probably adapt a pair of air tool wrenches to work.
What would be the fun in that? I wouldn't be able to justify the Haas CNC to the wife! :lol:

Ah! Now I understand ypur method of madness! :lol:
Post Reply