Bending stake pockets- how thick?

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Glenn Brooks
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Bending stake pockets- how thick?

Post by Glenn Brooks » Mon Apr 22, 2019 12:25 pm

Hello All,

I’d like to make up with a bunch of stake pockets for two or three flat cars. Now these will be 3” scale, in 12” gauge. So maybe twice the size of normal live steam pockets sold by our good vendors. Perhaps a 2” x 3” ID pocket, 5” end to end.
Something like this:
7694E09D-D565-444B-96CA-82130AC9BFE6.jpeg
Wondering what thickness of metal plate I should use? Even 16 gauge sheet metal seems a bit light, and not to scale...?
Anything thicker, I don’t think I could bend it with a typical cheap HF brake.

(I don’t have any metal brake capacity or serious hydraulic press ability, but considering buying a cheap HF brake, if it would work)

Also looking into having A pattern made up - but takes time, and producing castings seems like a pita for such a minor part.

Any ideas or suggestions?

Thanks much!
Glenn
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Motive power : 1902 A.S.Campbell 4-4-0 American - 12 5/8" gauge, 1955 Ottaway 4-4-0 American 12" gauge

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Russ Hanscom
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Re: Bending stake pockets- how thick?

Post by Russ Hanscom » Tue Apr 23, 2019 9:06 am

The last batch I had made were 1:1 scale for the narrow guage. Typical stock thickness was 1/4 or 5/16". A local shop had a big press and they knocked them out in short order.

If I convert the numbers correctly you will be needing something in the 1/8" thick, or slightly less, range. If you had a small hydraulic press of 5 tons or so, you could make a simple steel die. Might even to form them with a simple die in a good vise.

4elements
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Re: Bending stake pockets- how thick?

Post by 4elements » Tue Apr 23, 2019 12:16 pm

If you have an oxy/acet. welding torch and a vise you don't need any other tooling. With a welding tip you can heat a bend line, set it in the vise and bend it with pliers or vise grips. The un heated areas will stay flat. If the bends on the sides (I'd call them "truss bends") are necessary, I'd consider hot forming those with a swage.

Glenn Brooks
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Re: Bending stake pockets- how thick

Post by Glenn Brooks » Thu May 02, 2019 3:18 pm

Made up a couple of experimental stake pocket dies. Here’s the most likely iteration thus far. Figuring a stake pocket ID of 1.250” x 1.0”, using 3/16” flat bar at 3” scale. Might go down to 2.5” scale, but I think I prefer structural pieces to be slightly more robust, rather than to small.

Very interesting researching bending radius and formulas for allowances for elasticity with various thicknesses of metal.

Still need to Mill the top die to size, round the corners etc, then affix the pieces of the die together. Finally drill and insert the alignment pins and springs to top and bottom plates (don’t have a clue what the nomenclature is for the parts.)

Glenn
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rkcarguy
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Re: Bending stake pockets- how thick?

Post by rkcarguy » Thu May 02, 2019 3:45 pm

You're going to need some good tonnage to get that to fully form, I'm interested to see how it works out.

Russ Hanscom
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Re: Bending stake pockets- how thick?

Post by Russ Hanscom » Thu May 02, 2019 4:22 pm

I am thinking that about 10 tons will be adequate, possibly less.

Nice die set. I usually make mine a bit cruder, just to see if they work, and then if they do, rarely make a nice set!

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ccvstmr
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Re: Bending stake pockets- how thick?

Post by ccvstmr » Thu May 02, 2019 4:48 pm

Glenn, just happened to wander over when I saw your post.

Have made several simple dies to press 1/8" wire for 1.5" scale grab irons. Made similar dies for pressing 1/16" sheet metal into offset links. Used a 12 ton laboratory hydraulic press to do my forming. Some thoughts and comments for your consideration...

1) guide pins for upper/lower die alignment is a good idea. Spring pins work well.
2) can you mill a shallow recess in both top and bottom die pieces? Something to "set" the blank stock in so it doesn't wander during the press?
3) might want to round the corners of the top die piece. Else, the metal might have a tendency to "bow out" trying to get around those curves.
4) should allow extra clearance in the vertical areas between the die pieces. Else, it might be difficult to get the stake pocket out of the die set.
5) if you see "stretch marks" at the bends...either need to heat the metal ahead of time or increase the radius of the bends on the dies.
6) consider including your mounting holes in the die set so after pressing...drill the holes. Or, come back later on to drill the holes. You're looking for consistency. One fixture can provide 2 functions. Trim off excess material after the pressing/drilling operations are done.

That's all I have for now. Good luck. Carl B.
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Glenn Brooks
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Re: Bending stake pockets- how thick?

Post by Glenn Brooks » Thu May 02, 2019 8:17 pm

ccvstmr wrote:
Thu May 02, 2019 4:48 pm
Glenn, just happened to wander over when I saw your post.

Have made several simple dies to press 1/8" wire for 1.5" scale grab irons. Made similar dies for pressing 1/16" sheet metal into offset links. Used a 12 ton laboratory hydraulic press to do my forming. Some thoughts and comments for your consideration...

1) guide pins for upper/lower die alignment is a good idea. Spring pins work well.
2) can you mill a shallow recess in both top and bottom die pieces? Something to "set" the blank stock in so it doesn't wander during the press?
3) might want to round the corners of the top die piece. Else, the metal might have a tendency to "bow out" trying to get around those curves.
4) should allow extra clearance in the vertical areas between the die pieces. Else, it might be difficult to get the stake pocket out of the die set.
5) if you see "stretch marks" at the bends...either need to heat the metal ahead of time or increase the radius of the bends on the dies.
6) consider including your mounting holes in the die set so after pressing...drill the holes. Or, come back later on to drill the holes. You're looking for consistency. One fixture can provide 2 functions. Trim off excess material after the pressing/drilling operations are done.

That's all I have for now. Good luck. Carl B.
Hello All, thanks for the comments. I did a test Bend with 3/16” plate and one 90* v shaped bend, no problem. But, not the whole pocket - e.g. 4 bends simultaneously. Hoping for the best. It not, will drop down to maybe 12 ga sheet. A bit thinner material than 3/16”. (Something like .185” versus .200”)

Regarding Carl’s suggestions:

1) yep,I plan on drilling and installing guide pins. Bought springs yesterday.
2) no room for Milling a recess - my die stock is same width as the planned 2” wide pocket material. However, I think I can weld some small vertical pieces of flat bar on the sides and end of the dies to hold the stock in alignment.
3) also, yep will round the edges to a generous radius. That’s my next step I think.
4) regarding clearance? Thanks, didn’t think about that. Do you know if there is a formula for clearance? Or how much is enuf?
5) Iam thinking of a 3/8” radius for 3/16” stock? At least to start. Fortunately I have a set of radius end mills so shouldn’t be hard to increase radius if needed. Again - excellent tip - I haven’t done this before, so figuring on a learning curve.
6). cutting the edges? How do you do this?? I saw a video on punching holes, but not sure how to set up the die to trim the edges. Fall back - planning to whack away with my bandsaw. Maybe pre cut and form the actual cut to length blanks...? Again, not enuf experience to know the best way to proceed.

Hope to post a photo or two of the final steps in building the die, then results of the initial pocket forming.

Glenn
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Re: Bending stake pockets- how thick?

Post by 0351 » Fri May 03, 2019 7:42 am

Glenn,
Ive been looking into making 3” scale stake picks for my future DRGW narrow gauge build.
Unless you’re set on pressing them out, Rich Eton had good way to make some and posted some pictures of his stake pockets on the Backyard FB page.
https://www.facebook.com/groups/backyar ... 10?sfns=mo

“Making steel stake pockets for my wooden car bodies. I use 3/4" (1/16" wall thickness) steel tubing clamped onto a 1-1/2" by 1/16" steel flat bar as shown. Next, I braze along the entire length of the rectangular tube. Then cut into 1" lengths, drill four mountng holes in each one, clean up welds with an angle grinder and paint. Hope this is helpful to someone out there.”
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ccvstmr
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Re: Bending stake pockets- how thick?

Post by ccvstmr » Fri May 03, 2019 9:13 am

Glen, as you can tell, there's lots of ways to get from start to finish. Depends on your abilities and capabilities...and what kind of appearance you're shooting for with your end product. You didn't say if you're fabricating for yourself or will be offering pockets for sale to others.

From your response...

5) I am thinking of a 3/8” radius for 3/16” stock? At least to start. Fortunately I have a set of radius end mills so shouldn’t be hard to increase radius if needed. Again - excellent tip - I haven’t done this before, so figuring on a learning curve.
A: sorry, don't have any formulas for you. If you can't make the bends easily...your choices are bigger press, larger radius bends, thinner material. Larger radius should be easier to form than expecting "thick" material to form around a tight radius. But we're all on a learning curve here. So there's some degree of trial and error until you get the result you're aiming for. Can always start with smaller radii and go up...but it's difficult (without starting over) to start with large radii and want smaller.

6). cutting the edges? How do you do this?? I saw a video on punching holes, but not sure how to set up the die to trim the edges. Fall back - planning to whack away with my band saw. Maybe pre cut and form the actual cut to length blanks...? Again, not enough experience to know the best way to proceed.
A: wasn't implying to arrange your die set to perform bend, punch and shear operations at the same time. Although that's doable. Just takes more time to perfect the die set...and a larger press. At least with your die set...you can locate the mounting holes in the die...and drill those holes after the bending operation is complete. If the "mounting ears" are too long...can always cut those with a saw and belt sand the edges.

Keep us posted of your progress. Carl B.
Life is like a sewer...what you get out of it depends on what you put into it!
I don't walk on water...I just learned where some of the stepping stones are!
I love mankind...it's some of the people I can't stand!

Glenn Brooks
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Re: Bending stake pockets- how thick

Post by Glenn Brooks » Fri May 03, 2019 9:48 pm

Finished the die today and experimented making a few pockets. With my light weight hydraulic press (maybe 8 tons max) I can successfully press 1/8” x 2” x 5” lengths of flat bar into the desired shape. 3/16 (.197” thick) mild steel sheet metal was just a bit to heavy and wouldn’t form the top bends with my light duty press. So I guess Iam partially successful. I now regret selling off my nice old 30 ton hydraulic press last year, and replacing it with the small 8 ton bench top model. Sure could have used the extra push today.

I’ll probably grind the edges round and spot weld them to the frames.

Certainly at 1.6” scale, this arrangement is very doable with 8 ton press and using the lighter gauge material.

Here’s a few more photos of the die in final stage of completion.
EF459BAC-580F-490B-BB06-EAFAF42FD46C.jpeg
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Couple of examples of the stake pockets themselves follow below:
17166D3C-502A-4AD0-906F-F0C9D4E2023B.jpeg
1CBBD5F1-C0C2-45C4-844F-1E486497660F.jpeg
Also I shoot a couple of examples held up against the side of my existing drop bed flat.

My plan is to make a flat car with capability for stakes and a second work car with a deck and partial box car body - or maybe just a simple gondola, with stake sides, convertible to with seats for passengers.

Carl, yep, certainly I could push out some extras if anybody wanted some.
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