12" working railroad

Discuss park gauge trains and large scale miniature railways having track gauges from 8" to 24" gauge and designed at scales of 2" to the foot or greater - whether modeled for personal use, or purpose built for amusement park operation or private railroading.

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Topics may include: antique park gauge train restoration, preservation, and history; building new grand scale equipment from scratch; large scale miniature railway construction, maintenance, and safe operation; fallen flags; track, gauge, and equipment standards; grand scale vendor offerings; and, compiling an on-line motive power roster.
rkcarguy
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Location: Wa State

Re: 12" working railroad

Post by rkcarguy » Wed Feb 19, 2020 2:24 pm

I'm pretty much ready to start retrofitting everything onto the dozer to get it rolling on it's new rubber tracks. I need to trim away some of the old plate ribs that were under the engine where the front axle will now reside and move in a slot under spring tension, match drill the channel frame rail bolt holes through the body and then start welding in the rear axle, gussets, and spring perches.
I've also decided (If you didn't notice by the bolt pattern in the output shaft plates) I'm going to go hydraulic drive. The belt system on these is just too hokey and high maintenance to be of interest and getting it all in good shape would have only saved me ~$200 compared to going hydraulic. Plus it gives me the freedom to position the engine wherever I like as I don't have to line up any pulleys. The GX390 is already like trying to cram a watermelon into a mailbox in the dozers 16" wide body.
I ran some calculations based upon a .75 cu/in pump and two 6.15 cu/in hydraulic motors(from their flow charts):
Hydraulic reduction: ~16:1
Final Drive Chain Reduction 2.6:1 (I can also go from -2 to +6 teeth here on the 14 tooth driver).
Total Reduction ~41.6:1
"Big Block" GX390 or GX390 Clone 18ft/lbs torque x 41.6 =748ft/lbs x .88(advertised efficiency) = 658 ft/lbs of torque(potential).
Top speed at low pressure 2.4 MPH
Top speed at max pressure 1.6 MPH ( set max to 1,800 PSI).
Sprocket + track thickness comes out to 12-1/8" total "wheel" diameter, close enough to 1' that I'm calling that 1:1 for torque calcs.
Torque peak on the GX390 motors is actually around 2500 rpm, so peak torque should be around 1.1 MPH and should be a good "dirt pushing" speed.
That said, the max continuous torque on these hydraulic motors is about 120ft/lb which gives me 312ft/lb at each axle. Above that, and the relief is going to kick in on the hydraulic system. Should be good utilization of the engine without stalling it out at max pressure.

rkcarguy
Posts: 1469
Joined: Tue Aug 22, 2017 10:33 am
Location: Wa State

Re: 12" working railroad

Post by rkcarguy » Tue Apr 07, 2020 12:28 pm

I got the rear axle welded into the 4" channel frame rails I'm adding to the chassis, slipped the hubs on and installed the track sprockets for a test fit.
Second picture is just one track slipped into position for an idea what it's going to look like, no front axle or tensioning spring installed yet.
Work is still operating as "critical manufacturing", but I'm stuck home after that so might as well get some projects done!
dozer2.JPG
dozer.JPG

rkcarguy
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Location: Wa State

Re: 12" working railroad

Post by rkcarguy » Tue Apr 14, 2020 12:40 pm

Front axle, tensioning springs, and tracks are now installed. It "rolls".
FYI, anyone trying to convert one of these dozers to rubber tracks you need stiffer springs on the tensioners than the 250# ones I started with, they are too soft. I'll probably install 450# springs when I have it apart again for painting.
I have a couple options for mounting the engine. I can mount it sideways in there with the cylinder head sticking out under the fender(viewing from the front you'd see the pull starter and flywheel cover) and then mount the hydraulic pump direct drive on the crank, or spin the motor the other way and chain drive the hydraulic pump(would have to add a bearing bracket "cap" onto the pump-they aren't meant for side loads).
The empty area above the rear axle is going to house the hydraulic oil tank and battery.
Next step will be to cut the openings in the rear/sides of the body and install the hydraulic motor brackets, then take some measurements for the depth of the sprocket hubs.

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BigDumbDinosaur
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Re: 12" working railroad

Post by BigDumbDinosaur » Wed Apr 15, 2020 11:40 am

rkcarguy wrote:
Tue Apr 14, 2020 12:40 pm
...or spin the motor the other way and chain drive the hydraulic pump(would have to add a bearing bracket "cap" onto the pump-they aren't meant for side loads).
I do not recommend chain-driving the pump. The chordal vibration from the chain will do a number on the pump's bearing and seal. Better to use an H-series timing belt, which has nowhere near the chordal vibration of a roller chain.
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rkcarguy
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Location: Wa State

Re: 12" working railroad

Post by rkcarguy » Wed Apr 15, 2020 12:11 pm

BigDumbDinosaur wrote:
Wed Apr 15, 2020 11:40 am
rkcarguy wrote:
Tue Apr 14, 2020 12:40 pm
...or spin the motor the other way and chain drive the hydraulic pump(would have to add a bearing bracket "cap" onto the pump-they aren't meant for side loads).
I do not recommend chain-driving the pump. The chordal vibration from the chain will do a number on the pump's bearing and seal. Better to use an H-series timing belt, which has nowhere near the chordal vibration of a roller chain.
I'm wanting to direct drive it if possible, as it would position the engine to pull air in from the front and place the hydraulic pump right below the control valve for nice simple hydraulic plumbing. I need to get the pressure washer head to let go of the engines crank so I can remove it and play with fitment. The pump will be CCW if I run a belt drive or CW if I direct drive it, so I need to figure out which way I'm going to go so I can get a pump coming that is the right rotation direction.

rkcarguy
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Location: Wa State

Re: 12" working railroad

Post by rkcarguy » Wed Apr 22, 2020 12:17 pm

I put in a rather large "Surplus Center" order yesterday......2 hydraulic cylinders for the bucket lift and tilt, a hydraulic pump, love joy type coupling kit, and a dozen heavy duty castor wheels I'm going to use for intermediate wheels for the tracks.
I decided to go ahead with the loader modification at this point because I'll plumb all the hydraulics and paint everything all at once, and the machine will just be that much more useful.
I was able to draft up a linkage that will fit inside the front of the dozer and give me 22" of lift on the bucket. The engine will be mid-mounted sideways. Unfortunately If I had added "arms" to the outside of the dozer body to get much more lift height it would have created a very dangerous pinch point between the arms and the fenders as I lowered the bucket. The 22" height is plenty to dig into a gravel pile and spread it along my ROW, or load it into a hopper or gondola.

rkcarguy
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Location: Wa State

Re: 12" working railroad

Post by rkcarguy » Tue May 05, 2020 1:16 am

Added a much needed tool to the garage, picked up this 1946 South Bend 9C tonight. It’s an interesting piece because it’s got factory V-belt pulleys instead of the typical flat ones. Came with about 3/4ths of the change gears both chucks and a face plate. Only part missing is the thread dial. The spindle bearings are in excellent condition, and if you snug up the carriage lock and start moving the carriage down the ways it’s pretty consistent until it hits the end by the tail stock where it firms up a bit. Need to bolt it down and get a belt and I’ll give it a try. It’s really cool to see “made in USA” on the chucks and everything!
29812E4D-48DA-4891-8D64-5D6AFDBCA09E.jpeg

Pontiacguy1
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Location: Tennessee, USA

Re: 12" working railroad

Post by Pontiacguy1 » Tue May 05, 2020 7:23 am

I like the V belt better, although I've seen people use an automotive flat belt and get good results instead of the leather flat belt. I'm thinking about doing that to my own lathe. I've seen a few of these that were 'retrofitted' to use a V-belt. Some would change the pulleys, some would cut V-belt grooves into the flat belt pulleys. By the mid-1940's they may have been giving a V-belt option from the factory as well. I just know that several that were originally flat belts have been converted. Obviously a lot of people got tired of the flat belts.

Also, a thread chasing dial was an option on these, and not all of them had it. I've had two 9" south bend lathes, and neither had the thread chasing dial. Looks like yours has the manual cross-feed saddle on it. Power cross-feed was also an option, and neither of mine had that either. Ditto for quick change gearboxes. These lathes could be ordered bare-bones or with quite a few options. Most seemed to be towards the bare-bones end of the spectrum. Both of mine look a lot like yours does.

Congrats on the lathe. They are pretty decent machines and can do a lot of work if you are patient with it. I've found that having one of these around is very useful for smaller items and especially stuff like piping and small fittings. There's a lot of times that I go to this lathe instead of the big lathe.

rkcarguy
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Joined: Tue Aug 22, 2017 10:33 am
Location: Wa State

Re: 12" working railroad

Post by rkcarguy » Tue May 05, 2020 11:02 am

It is the bare bones setup, that's ok though. The price was right for the area (I think we get a lot of Boeing retiree's that want to continue to "play" and hobby size single phase or 110v machines often pull a premium here).
The main purpose for this little lathe is I'll be able to setup for finish turning all my angles on the wheelsets and not have to tear down the setup every time I'm done like I have to do on the work lathe. The wheelsets are roughed in so I just have .030" -.060" to remove to finish everything up. Surely I'll make spacers and fittings and other such small oddities along the way of building my locomotive and rolling stock. It looks like I'll be able to get about 24" between centers with the 42" bed, so it will meet all my axle length and wheel size needs for everything I'm wanting to build so far.
My QCTP will fit this with up to 3/8" tools, just need to get a proper T-nut coming.

I'm wondering if the whole head was changed out? The spindle bearings feel really nice, and not only that but another interesting feature is that the oil cups are placed LOW on the front of the bearing bosses, instead of up top like I'm used to seeing. The bed of the lathe is serial #'d and checks out to a 1946 workshop lathe, most likely a "C" from comparing images online.

rkcarguy
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Joined: Tue Aug 22, 2017 10:33 am
Location: Wa State

Re: 12" working railroad

Post by rkcarguy » Tue May 05, 2020 11:42 am

These V-belt type pulleys on these use a "Section C" belt, 7/8" wide?

Glenn Brooks
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Re: 12" working railroad

Post by Glenn Brooks » Tue May 05, 2020 2:16 pm

Ryan, Congrats! Looks like a nice addition to the shop. How about posting a picture of the V belt pulleys and set up? Is this an under table or back gear set up?

I set up my little Dalton 7” lathe with a SB backgear pully arrangement with a V belt driving from the motor and an automotive serpentine belt to the headstock. These automotive belts are very effective. Wondering if yours also V belts to drive the headstock?

You can get green replacement V belts at automotive stores that are more heavy duty than the black automotive ones - they use them on riding lawn mower decks - last a lot longer. Little Machine Shop sells a nice little QCTP Kit. You might be able to fit their larger size on your SB9 - the parting tool holder is pretty flimsy on the smallest QCTP.

I do all kinds of small stuff on my little Dalton. Sure you will enjoy your SB.

Glenn
Moderator - Grand Scale Forum

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

Ahaha, Retirement: the good life - drifting endlessly on a Sea of projects....

rkcarguy
Posts: 1469
Joined: Tue Aug 22, 2017 10:33 am
Location: Wa State

Re: 12" working railroad

Post by rkcarguy » Tue May 05, 2020 3:37 pm

Glenn Brooks wrote:
Tue May 05, 2020 2:16 pm
Ryan, Congrats! Looks like a nice addition to the shop. How about posting a picture of the V belt pulleys and set up? Is this an under table or back gear set up?

I set up my little Dalton 7” lathe with a SB backgear pully arrangement with a V belt driving from the motor and an automotive serpentine belt to the headstock. These automotive belts are very effective. Wondering if yours also V belts to drive the headstock?

You can get green replacement V belts at automotive stores that are more heavy duty than the black automotive ones - they use them on riding lawn mower decks - last a lot longer. Little Machine Shop sells a nice little QCTP Kit. You might be able to fit their larger size on your SB9 - the parting tool holder is pretty flimsy on the smallest QCTP.

I do all kinds of small stuff on my little Dalton. Sure you will enjoy your SB.

Glenn
This SB has the back gear arrangement with the pulleys and motor "tower" that mounts behind the lathe. I'm going to slide my bench to the left where there is a gap behind it, and add on a little more bench there to support that. I just picked up one of those power twist universal sectional belts so I don't have to mess with taking the spindle apart. The electric motor has a V-belt pulley on it and V-belt, then it's wrapped around the large flat pulley on the "tower". It's kind of goofy but I'll try it before I swap the motor pulley and add a serpentine belt. The speed adjusting belts are also V-belt, not flat. From what I can find, this was fairly rare and I'm not a fan of the flat belts so I'm happy it has a V-belt pulley head.
I already have a 200 series QCTP setup with extra holders and an indexable carbide boring bar I bought for the "other lathe". It's a little big, but with the holders adjusted all the way down it will put 3/8" tools just a tad below center. I might have to mill down the holder for the boring bar I haven't tried that one yet.

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