crosshead slides

[pockets]

Gentlemen,
As near as I can determine, from photos and the 1/4" scale drawings I have, my project Baldwin has a two or three bar crosshead slide. It appears as though the crosshead projects down between two bars, with a third bar on top, capturing it. Does this sound right?

From the side, it looks like two closely spaced bars mounted above cylinder center line. However, I got one view at a slight angle and it looks like their might be three bars. This is on an 1890's vintage Baldwin.

Does anyone have a good drawing or picture of the bars and how they mount to the cylinder head?

Best regards,
Greg B.

[pockets]

Hi, Gang,
I stumbled into a drawing ( pg.17, June,1972 L/S ) that has a sectional view at the rear support for the crosshead guides. If my bifocals aren't fibbin' me, it looks like four bars. It even makes sense to me.

Best wishes for a happy New Year,
Greg B.

[GWRdriver]

Greg,
I can't recall seing one with anything other than 1, 2, or 4 bars. Anything else, such as 3, would create unbalanced resistance where the crosshead would want to twist in the direction of the lesser number of bars.

[pockets]

GWRdriver,
Thanks. I've pretty much ascertained that it's a four bar system. The give away is the oil cup, mounted to the slipper, that protrudes between the top bars.

Interrestingly, though, there is a casting that bolts to the support crossmember. This casting serves as the mount for all four bars and the crosshead pump. If I stack two magnifying (SP) glasses and squint, I can just make this out!

Happy New Year,
Greg B.

[Jan-Eric Nystrom]

My 1872 Baldwin has a 4-bar crosshead slide.

Some pictures here:
http://www.saunalahti.fi/animato/3003/3003x.html
http://www.saunalahti.fi/animato/3003/3003aa.html

Greetings,
J-E

[pockets]

Jan-Eric,
As usual, thanks. There is a lot of help there.

Could you, please, contact me via e-mail?

Happy New Year,
Greg B.

[andypullen]

The Pennsy E-6s Atlantic used a 3 bar crosshead. The G-5 4-6-0 also used that crosshead. I think some of their 3000+ Consolidations may have used that crosshead, as well. It's a very lightweight looking unit and it worked well enough in passenger service. I can copy a drawing of it for anybody that's interested.

Andy Pullen

[GWRdriver]

Andy,
Without digging out the Sat Steam E-6 construction series drawings, can I assume that one of the three bars, the upper one maybe, is centered over the piston rod?

[andypullen]

Hi Harry,

Yes, you are correct. The top bar is the width of the 2 bottom bars plus the bottom part of the "tee" section of the crosshead. (Plus the required clearances....) And its centerline is the centerline of the piston rod.

Andy Pullen

[Bill Shields]

Yes, it's in my new (1941) Loco Cyclopedia...neat to have this to look things up....

[GWRdriver]

I've got a crosshead decision to make myself soon, on my 2X Tich. The rear cyl head set up for a stout single bar (above the piston C-L) but due to the closeness of the crankpin cap behind the crosshead I'll use all the space I can conserve in that area. I've considered doing a T-slide crosshead, rather than have it wrap around the bar, but considering this is a dock or quarry shunter I want to avoid modernizing it too much.

[fred v]

i had never thought about it until recently but in forward gear all the crosshead pressure against the slide bar is upward for both strokes. in reverse the pressure is downward against the bottom bar.

this is important to think about with regard to the lubrication. most crossheads have an oil cup on the top so methods have to be incorporated to get the oil to the underside of the slide bar for forward gear running!!
fred v

[Jan-Eric Nystrom]

<font face="Verdana, Arial" size="2">Most crossheads have an oil cup on the top so methods have to be incorporated to get the oil to the underside of the slide bar for forward gear running!!</font>

Often it's done by having holes drilled straight through the crosshead, at strategic points, as well as a few oil grooves.

Greetings, J-E

[This message has been edited by Jan-Eric Nystrom (edited 12-28-2005).]

[Jan-Eric Nystrom]

Oops, meant to edit the previous...


[This message has been edited by Jan-Eric Nystrom (edited 12-28-2005).]

[Unka Jesse]

Pockets et al, I found this page in volume three of my ever handy dandy Audel's Engineers and Mechanics Guide from 1921. It illustrates the three bar crosshead guide along with others. The guide in the photo is called a three bar, but it is actually all in one piece in this instance. Looks like a very substantual design to me. Ooops, I thought I had the text that went with the guides, but apparently either I or Photobucket clipped it off. Anyway, the three bar guide is next to the bottom example.

BTW: The one bar guide at the top is not recommended for anything other than slow moving locomotives such as switchers if the drivers are small. This is to help keep dirt from being thrown up on it because of its proximity to the ground. Seems this would be the case with any guides, but I only quoted the text, more or less.

Maybe this eight book series of manuals should be reprinted by Lindsay?? http://bbs.livesteam.net//smile.gif
http://i31.photobucket.com/albums/c400/Unkajesse/be6f559b.jpg

[This message has been edited by Unka Jesse (edited 12-29-2005).]

[This message has been edited by Unka Jesse (edited 12-29-2005).]

[fred v]

what material do you guys use for slide bars?
fred v

[GWRdriver]

Fred,
The jury is kind of out on this one for me. My plan is to find something hard and wear-resistant in its normal state but since I'm not up-to-the-minute on metalurgy I don't yet know what that will be. Maybe an annealed die steel, something that doesn't required much additional work beyond machining, and maybe grinding at most. I don't plan to use anything that requires hardening.
Jesse those Audels drawings are very informative, although I wouldn't have called picture #3 a "3-bar" crosshead. I don't know what I would call it, it may very well be universally known as a 3-bar, but that wasn't what first came to mind.

[pockets]

Fred,
It is good engineering practice to use a sacrificial wear surface. I intend to use either brass or bronze slippers on my crossheads, where they contact the guides. I'll probably use cold rolled or ground stock for the guides.

Happy New Year,
Greg B.

[Bill Shields]

Greg:

FWIIW:

I harden and grind all my guides for every engine since loco #2 (don't ask)....doesn't take all that long...and is there for the life of the loco

DON'T FORGET to put the lube system in them before you harden (loco #3 lesson)....

[GWRdriver]

Bill,
So what steel do you use?

[Bill Shields]

on my current project, I used D-2.

I roughed it out, gave it to my brother in law who owns a tool and die shop (has heat treating furnaces).

Got them back semi-straight...stuck on the surface grinder and finally ended up with really hard, straight 1/2" square guides that will last the life of the engine...are file hard.
http://www.netgazers.net/~shields/photos/crosshead.jpg

My Hudson has W-1, or the German equivalent thereof (I think)...was supplied 'gratis' by my employer.

Engine #1 (long deceased), had 4140 ground to size..didn't heat treat.

2-6-0 Porter was A-2, heated in home-made furnace. Came out OK...was able to drill holes with carbide drills for anchors / oil holes (lesson learned)...



[This message has been edited by Bill Shields (edited 12-29-2005).]

[Jan-Eric Nystrom]

Nice crosshead! Obviously, there's a sacrificial bronze piece attached with those bolts, right?

Greetings, J-E

[Bill Shields]

Yes...

It has oil distribution grooves / through holes to the bottom guide..

[fred v]

i've been looking at oil hard tool steel but it is really pricy. i need 5/8x3/4 10" long. the stuff comes 18" or 36".
fred v

<font face="Verdana, Arial" size="2">Originally posted by GWRdriver:
Fred,
The jury is kind of out on this one for me. My plan is to find something hard and wear-resistant in its normal state but since I'm not up-to-the-minute on metalurgy I don't yet know what that will be. Maybe an annealed die steel, something that doesn't required much additional work beyond machining, and maybe grinding at most. I don't plan to use anything that requires hardening.
Jesse those Audels drawings are very informative, although I wouldn't have called picture #3 a "3-bar" crosshead. I don't know what I would call it, it may very well be universally known as a 3-bar, but that wasn't what first came to mind.</font>

[andypullen]

<font face="Verdana, Arial" size="2">Originally posted by fred v:
i've been looking at oil hard tool steel but it is really pricy. i need 5/8x3/4 10" long. the stuff comes 18" or 36".
fred v

</font>

Hi Fred and Harry,

4142 pre-heat treated would make nice guides. It's not too difficult to work with being about 36C on the Rockwell scale. I've made quite a few parts out of it and it holds up well.

Speedy Metals will sell you what you need...1-888-744-4140. (usual disclaimers here, I'm just a satisfied customer) If you need it ground; I can do that for you.

The full sized locomotives didn't use hardened tool steel for their guides. From my experience on N&W steam; they were made from a good grade of steel. I use annealed tool steel or the above mentioned 4142. Never had a problem.

Andy Pullen

[GWRdriver]

&gt;&gt;The full sized locomotives didn't use hardened tool steel for their guides.

Andy,
I would not have guessed tool steel of any kind because I'd figure that whatever they used would have needed to avoid any level of brittleness. Perhaps these were made of the same material as rods, a good forged alloy steel.

Thee 4142 sounds like a viable alternative. As I said, I really don't feel compelled to use something that requires heat treating necessarily. After all, the original simply called for BMS.


[This message has been edited by GWRdriver (edited 12-30-2005).]

[Jan-Eric Nystrom]

Well, I used untreated key stock for the slides on my 0-6-0, and the crosshead parts are of hardened gauge plate.

After two years of running, I have just re-assembled the engine after taking it apart completely. There was practically no wear at all of the key stock slides, and none whatsoever on the hardened crosshead parts. This despite the fact that thhose crossheads were really dirty and gritty after all the running.

My 4-4-0 has both the slides and the crosshead made of key stock, with no problems there, either, after four seasons of running.

If there ever is substantial wear, those pieces of key stock will be rerally easy to replace - hardly any machining on them...

Greetings, J-E

[GWRdriver]

J-E,
This tends to lend some credence to the thoughts I have when increasingly answers to live steam questions arising now seem to always involve fairly complex industrial processes, far beyond what the founding fathers used and survived on nicely.

I wonder how much of an improvement in performance (longivity, etc) it actually results in. It's one thing if someone has access to industrial materials and processes, I'd say use the best technology you have available to you. But if you don't, or it would be difficult and expensive to have it, will you not be all that bad off without it. I'm beginning to think not.

[Bill Shields]

I started hardening things because in the desert (Saudi) the 'sand' was like baby-powder dust and got into everything.

A friend's OS Porter absolutely ate up a set of guides in a summer - the dust became grinding compound - no way to keep it out...so I started hardening things.

I have 'adjusted' the crosshead shoes once on the Hudson since 1982 when I started running it - I opened the holes up a bit and stuck some shims under the shoes to take up what I had to mill out from 'scratches' from the 'dust'.

Is it needed here?...you are right...probably not, but getting the
guides out of my Hudson is a MAJOR undertaking...and with hardened guides, I know that I won't need to, so I can set it and forget it....my kind of assembly.

Since I personally don't have the problem of availability of material or heat treating services...why not go with what I know works?

[pockets]

Hi, Gang,
This is really enlightening. The varied approaches, to a given product, from successful builders, allows an individual with some historical knowledge and an understanding of what these processes entail to make an informed decision. I guess that's what these forums are about and for that, I thank you.

Right now, because of this discourse and the masses involved with my large scale model, I am leaning toward the 4142 and bronze slipper inserts with oil grooves and passages.

Thank you and Happy New Year,
Greg B.

[GWRdriver]

Bill,
We're not being critical of your choices, we're just looking at the various alternatives.

[Bill Shields]

The thought never crossed my mind....just explaining why I did what I did so that everyone can understand that I am not TOTALLY crazy....

HNY to the lot.....hic!

[Unka Jesse]

Harry et al, Here is the text for the crosshead guides pics that somehow did not carry over to Photobucket and onto the Steaming Bay.

http://i31.photobucket.com/albums/c400/Unkajesse/Crossheadguides.jpg

Unka Jesse

[srrl5]

I've been using 1/2" square cold rolled steel for 30 years. Have replaced the bronze liners a few times but the bars are still fine.

David

[Bill Shields]

Jesse:

My 'cyclopedia has what would then be called a 5 bar guide...looks like a Christmas tree - your 3-bar guide, stacked on top of another one....PRR used it and evidently Lloyd crossheads used it.

Talk about killing a fly with a shotgun...

[fred v]

my Chloe uses a single bar like the top pic. the crosshead has a nose on it like the 3rd pic. i had a problem with the nose breaking off. i soldered it once and it broke again. i made new ones from steel (original was bronze casting) and they are holding up OK.

i wondered reading what was mentioned about bending the slide bar. if too much clearance came between the bar and crosshead the crosshead could rock or rotate which may have caused my problem.
fred v

<font face="Verdana, Arial" size="2">Originally posted by Unka Jesse:
Harry et al, Here is the text for the crosshead guides pics that somehow did not carry over to Photobucket and onto the Steaming Bay.

http://i31.photobucket.com/albums/c400/Unkajesse/Crossheadguides.jpg

Unka Jesse

</font>

[Bill Shields]

If the bar is not sufficiently 'stiff', it can bend...

'Stiffness' can be 'created' either with more material, creative shapes that resist bending along the direction of force and / or where the bar is braced....or all 3 combined.

The need for 'stiffness' can be minimized by using longer main rods to reduce the 'angle' between the piston rod and the crank pin on the main driver.

I have seen some of the most flimsy guides imaginable work without problems, and have seen some that I thought would drive the Titanic fail.

When working with tool steel (hardened), the trick is hard but not brittle...which requires a bit of heat treating skill to 'draw' it back a bit..that and avoidance of sharp corners from whence cracks can propogate...

[srrl5]

For better tracking I have a low load rate springs with more preload which has worked great. When working hard the angle load from the main rod will rock the locomotive side to side enough to make the bell ring. Being a ride on tank loco it makes for an interesting ride.

David

[Unka Jesse]

<font face="Verdana, Arial" size="2">Originally posted by srrl5:
For better tracking I have a low load rate springs with more preload which has worked great. When working hard the angle load from the main rod will rock the locomotive side to side enough to make the bell ring. Being a ride on tank loco it makes for an interesting ride.

David</font>

David, my late father, a confirmed diesel man, always claimed that a steam locomotive would take a bite out of the grass on one side of the track and then reach over and eat some grass from the other side. I haven't experienced this with my models, but all of them have rather long main rods which would help alleviate the problem.

Unka Jesse

[srrl5]

<font face="Verdana, Arial" size="2">Originally posted by Unka Jesse:
David, my late father, a confirmed diesel man, always claimed that a steam locomotive would take a bite out of the grass on one side of the track and then reach over and eat some grass from the other side. I haven't experienced this with my models, but all of them have rather long main rods which would help alleviate the problem.

Unka Jesse

</font>

Jesse,

I don't see it as a problem, like I said it makes for an interesting ride. http://bbs.livesteam.net//smile.gif

David

[Unka Jesse]

My Filer and Stowell would be expected to have the shimmy, she shake, she wobble with those cylinders flopping up and down, but surprisingly, it runs smoothly.

Unka Jesse
http://i31.photobucket.com/albums/c400/Unkajesse/filerandstowell.jpg

[Jan-Eric Nystrom]

You know, the only time I really experience severe wobble is when I brake, going downhill, by using reverse power on my 4-4-0. What a wiggle!

Greetings, J-E

[Unka Jesse]

Just you wait till Ears McFly's boss Al Messy gets his "Ugly Locomotive" up and running. Vertical oscillating cylinders direct connected to front drive wheels and I keep telling him that it will go down the track hippity hopping along. http://bbs.livesteam.net//biggrin.gif

Unka Jesse

[EARS_MCFLY]

The Fat Lady ain't sung yet, Jesse. As stiff as the springs are on the front axle, it is almost like a solid suspension.

[Bill Shields]

One of the primary times when I wobble is when I have had too much squeezin's and am about to 'brake' something because I am on the way to the floor...which I try to avoid while around running machinery.

[fred v]

Bill, i read somewhere but can't find it that main rods should be 3.5 times the stroke. i think that was the number. this is to reduce pressure on slide bars as you mention.
fred v

[QUOTE]Originally posted by Bill Shields:
[B]If the bar is not sufficiently 'stiff', it can bend...
The need for 'stiffness' can be minimized by using longer main rods to reduce the 'angle' between the piston rod and the crank pin on the main driver.

[Bill Shields]

Fred:

That may be a good number....it seems reasonable...the ACTUAL number would be a function of stroke, piston size, boiler pressure, rod length, cross-head guide strength (as well as how it is supported...ends or center)...all too much to worry about for a 'hobby'....

I personally have never worried about it, since the models we are making are typically 'similar' to something that was already designed...and worked....very few people make models of 'duds'.....

The longer the rod, the less 'side thrust' will go on the cross head....and of course, the greater 'mass' bouncing around between the main rod and the head.

Normally, these forces / reactions / imbalances, are things that modellers don't worry about....I have enough to worry about just welding my boiler together. My current chassis runs just fine on air at speeds well beyond anything it will run when actually on the track...so ignorance is bliss and I am a truly happy camper