Manual ground throws on the DC&M

dawgnabbit · September 24, 2011, 4:19pm

Hi, All… John asked for details of the “barrel-bolt” ground throws used on the DC&M. Once again, I’ve just ripped off the work of others: in this case, Fr. Fred’s inspired Original KayDee (Patented) Barrel-Bolt Ground Throw. I have made a few modifications to the original to suit my situation: (a) it’s mounted close-coupled to the switch itself, and (b) the points are lightly spring-loaded to the stock rails in either position, so a loco can go through “wrong way” without derailing. Obviously, I’m more interested in low maintenance and ruggedness than I am prototype fidelity:

I don’t claim anything original here, except maybe the way I got a very light spring loading using cheap ballpoint springs (with inactive coils clipped off). Most of the length of the springs is hidden down in counterbores within the barrel bolt. The reach rod slips all the way through the bolt and is free to rotate. The spring stops are just brass donuts soldered to the reach rod so that the springs are not under compression when the bolt-handle is mid throw.

For a mounting platform, I just clipped three ties off a spare LGB tie strip, opened up the ends, and coupled them to the Tain-Li R7 switch with “filler strips” sawed from ¼ inch ABS plastic sheet. Plus a few stainless cap screws. It’s very secure:

I’d prefer to use only two ties, of course, but the Train-Li switches have a power routing reed relay in that center tie, so it can’t be used for mounting purposes. There really aren’t any finicky adjustments except perhaps getting the spring pressure equal on both points. The way to do this is to bend the reach rod to lengthen or shorten the throw a tiny bit.

Construction is all solid brass, plastic, and stainless steel (except the ballpoint springs), so it should weather well. If the springs rust out, I’ll wind some brass or stainless ones. Here is a link to the details of how I machined the bolts: http://1stclass.mylargescale.com/dawgnabbit/switch%20drive/instructions.pdf Cheers

JRad · September 24, 2011, 4:25pm

Thanks! I don’t have the metal working machinery to copy your design exactly, but it has given me some ideas

dawgnabbit · September 24, 2011, 4:32pm

John, you’re welcome…

Don’t give up: brass is pretty easy stuff to drill. I used a lathe, but you could do it just as well with a drill press. Or if your hands are really steady and your aim is true, a hand drill will work. Just go slow and clear chips frequently.

Steve

Ric_Golding · September 24, 2011, 11:19pm

Steve,

Jon’s hands aren’t steady and his aim has been off for years, but he’s pretty resourceful. I’m sure he is able to build a robot and a circuit to do all the work.

JohnM · September 24, 2011, 11:20pm

Those are awesome. Maybe my brother will take a stab at them, since I found that drill press cheap (hint hint). Before you know it, someone will be trying to hawk them in Garden Railways for fifty bucks a piece.

Ric_Golding · September 24, 2011, 11:22pm

John Miller said:
Those are awesome. Maybe my brother will take a stab at them, since I found that drill press cheap (hint hint). Before you know it, someone will be trying to hawk them in Garden Railways for fifty bucks a piece.

John, You're against free enterprise?

jtmsmike · September 25, 2011, 4:17am

Yeah, but you didn’t get the vises! Gotta make a Harbor Freight run. BTW: How’s the new (used) table saw working out? LMFAO! Just thank your higher power your life doesn’t depend on Juniper Creek and I ain’t talked 'bout the one on TV! I do believe that there is a “screener” residing at the Creek that is controlling data flow. I am kind of glad to on the “S” list right now.

jtmsmike · September 25, 2011, 4:40pm

Steve, could I pain your for some dimensions? As a 32 year aerospace dude, I am kind of anal retentive. Your design is awesome. Would be really sweet to have a set of drawings to share with the troops. I would be willing to make some up once I get the recipe correct for parts and shipping in limited quantities. This would be a good gap filler when I am between structure work which I have 9 more projects sitting on the shelf. I just took every bit of HO that John Miller had in the garage and put it up in the rafters. You wouldn’t believe how much room I have now. Even took on a 4 building order from his friend James.

dawgnabbit · September 25, 2011, 6:07pm

Hi, Mike

I didn’t actually bother with drawings, because I only needed a few, and dimensions aren’t overly critical. But I can tell you the key dimensions.

First, and perhaps most important, is to get two-inch SOLID BRASS barrel bolt latches, not the brass-plated steel ones. The handles on the steel ones are staked in place, making disassembly/reassembly a real pain. You want threaded handles, which the solid brass ones have.

The Deltana Model 2BB, available on-line for $4-$5 each, is good. I bought the same thing off the shelf at ACE hardware. Sorry, I didn’t write down the ACE part number, but it’s easy to find. I bought a box of the cheapest retractable ballpoint pens that Wally World sells and stripped the springs out of them. Everything else was lying around the shop. Come to think of it, there isn’t much else…

The counter-bores in the bolt are .160 diameter x .500 deep. Tolerances not critical. The springs should slip loosely inside.

The through-bore is .070 diameter. The reach rod is .063 brass, available on-line or at the local hobby shop or hardware store. Look for the K&S display.

You will need to remove about 1 or 1.5 threads from the end of the handle to clear the through bore. Just file the end of the threads until the reach rod slips through the bolt freely. Or turn the excess threads off in a lathe (That’s why I had to turn the taper off the handle first. And you say you’re anal retentive…)

My stop collars are thin disks of brass sliced from a .187 diameter brass rod and drilled .063 through, but anything that retains the springs will work. Nothing critical there. Solder them to the reach rod so neither spring is compressed.

The machining instructions (http://1stclass.mylargescale.com/dawgnabbit/switch%20drive/instructions.pdf) are pretty explicit, but if you have more questions, don’t hesitate to ask.

One last thing: The basic design actually came from Fr. Fred, who says it’s patented, but freely available to anyone making a small donation to a local animal shelter. Let your conscience be your guide.

Hope this helps!

jtmsmike · September 25, 2011, 7:08pm

Thanks Steve. Those instructions are more than helpful.

dawgnabbit · September 26, 2011, 7:30pm

I found the information on the ACE Hardware part: ACE brand 2" barrel bolt, solid brass, P/n 5300181.
Here’s a source: http://www.acehardwareoutlet.com/ProductDetails.aspx?SKU=5300181
Steve

jtmsmike · September 26, 2011, 7:41pm

Thanks Steve - AGAIN!!! More than helpful. I appreciate it greatly and BTW probably my brother John does too. I can “hear” him drooling over having these switch throws up in Lake Arrowhead.

JRad · September 27, 2011, 12:55am

OK. That’s a great price on a solid brass barrel bolt. I was thinking they might cost as much as a throw like the Tenmille.

If I do make these, I’ll probably use threaded rod and stop nuts rather than soldering the retainers to allow for adjustment as the springs weaken.

jtmsmike · September 28, 2011, 2:31am

If you are going to use all-thread, potential for binding if the center bore is not large enough and entrance holes beveled/counter sunk. Steve, any thoughts?

dawgnabbit · September 28, 2011, 3:13am

I should think 1/16 all-thread would work okay; just try it and see.

The bolt itself is 2 inches long, and the ends are both counter-bored a half-inch deep. That means the .070 center bore is about 1 inch long. plenty of threads will be in contact with the walls of the bore at all times, so I don’t think there will be any internal binding.

FWIW, if adjustment is the issue, it’s a simple matter to touch the soldered stop collars I use with a small iron and just slide it to a new position. Quick and permanent.

Steve

Joe_Zullo · May 1, 2013, 9:46pm

Steve Seitel said:
I found the information on the ACE Hardware part: ACE brand 2" barrel bolt, solid brass, P/n 5300181. Here’s a source: http://www.acehardwareoutlet.com/ProductDetails.aspx?SKU=5300181 Steve

Steve,

I know this is an old thread, but I’m sort of new here and wanted to try this ground throw to update one of my old beat up Aristo switches. I downloaded your fine instructions and went to ACE and then went to work on my Micro lathe and banged one out. I used model airplane wheel collars instead of soldering brass collars which gives me adjustability without using your square bend. I installed it on sight and it works wonderfully. Thank you for your precise instructions. I love making something that is BETTER than something that can be purchased. Now I have three more to make!

Here’s a picture of my version installed…