A few refinements to the Hobby Holidays Rolling Road

Rob Pulham

Western Thunderer
I have had a Hobby Holidays Chassis Jig for a good number of years and I am really pleased with it.

It came with additional components to make it into a rolling road. I do use this but I have never really been happy with it. The rollers are set at 32mm apart to suit Peco track but as with the inherent slop in Peco track I find that the loco being tested tends to hunt from side to side never really giving a true reflection of how it's actually running. I tried once a few years ago to reduce the distance by adding washers behind the roller bearings but my washers were too wide and all it did was seize up the rollers so I took them back out. When I bought my mill I had the bright idea to mill of 0.5mm from each spacer to reduce the slop but never got around to it until yesterday. I was about to dismantle the roller sets to mill them when I remembered that a former guild member had given me a collection of various nuts, screws and washers so I had a look through them and found some 0.5mm thick washers that were also very thin in terms of the washer area which while acting as a spacer to take off 0.5mm didn't inhibit the movement of the bearings.

Hopefully this photo will show what I am struggling to describe.

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This cured the hunting immediately, so I can't recommend it enough to anyone else experiencing the same issue.

If you are connecting power directly the the motor the HH rolling road units are fine but if you actually want to test pickups then that's a bit more interesting because the unit really isn't designed for it. For years I have used a bit of a lash up of some lengths of copper wire and some crocodile clips to transfer power to each of the wheel cradles.

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After doing a recent repair job for a fellow member which required testing pickups I thought it about time I did something a bit better. I found in my stash of "it will come in useful some day" materials a strip of aluminium which when cut into two pieces was perfect to create two bus bars. I milled some slots in them to allow adjustment to cover all my rolling road cradles (mine is a 5 axle jig).

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As luck would have it in the front of the rolling road units is a hole to allow you to fit a hex key to get at some cap screws on the rear. These were just the right size to tap M4 while still allowing the hex key passage. There are also a set of holes already tapped M4 on top of the adjusters which will pass the current to the other side.

This is the bus bars in place. All that's left for me to do is shorten a few cap screws to make them fit better. The end tabs allow me to connect via crocodile clip either DC or DCC

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To prove it all works I took a short video but instead of there being a boring video of a loco on the Rolling Road I played with the video editor to to turn it into a cartoon.

 
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simond

Western Thunderer
Rob,

you’re passing the traction current through the ball bearings. This is an absolute no-no-never in the “real world” as it causes erosion of the balls and the tracks in which they run. You can see brushes to avoid it on real railway stock, and in gearboxes, even the prop shafts of my boat have earthing brushes to prevent electrolytic corrosion, and that’s a matter of a couple of volts max., but you don’t want any current passing through rolling element bearings.

it will also happen in the 7mm world, though I imagine it’ll take quite long time for any damage to become apparent.
 

Rob Pulham

Western Thunderer
Hi Simon,

I am aware of it, but for the amount of running that my rolling road gets in a year, I doubt it will ever be an issue. But if it is, it's cheap enough to replace the bearings.
 

OzzyO

Western Thunderer
Rob,

the bit that I've never liked about the rolling part of the H. H. jig is that the wheels are always running on a "sharp" corner of a bearing. It would be better if the bearing had the correct 1:20 (approx. 3deg) taper on the faces. But that is a LOT of fine turning to do for a 5 axel jig that is 20 small caps to do.

I did think about it!

OzzyO.
 

Rob Pulham

Western Thunderer
Rob,

the bit that I've never liked about the rolling part of the H. H. jig is that the wheels are always running on a "sharp" corner of a bearing. It would be better if the bearing had the correct 1:20 (approx. 3deg) taper on the faces. But that is a LOT of fine turning to do for a 5 axel jig that is 20 small caps to do.

I did think about it!

OzzyO.
You are one up on me Paul, I haven't even thought about it...
 

simond

Western Thunderer
Easy enough turning job, 1:20 reverse (ie smaller end near the chuck) taper on the outside, drill clearance for the bearing screw, counterbore to the outside diameter of the bearing itself, ream if necessary, part off, repeat.

probably don’t want to use ally, but nickel, brass of steel would be ok.

the reaming will be difficult because the hole in the part will only be a few mm deep. Probably need to bore to size, with square front tool.

it’ll take up the gauge free play too. No washers required.
 

Ian@StEnochs

Western Thunderer
Rob,

I found that the sharp edge of the ballrace wore a groove on the tyre, I discovered this after an exhibition demo when I found that the loco I had running for a couple of days had a deep groove on all the driving wheels. Now I only use my rolling road very sparingly to check valve gear etc. Any running in is done on the layout or test track which is actually a better test whith the rods actually doing the job they were meant for.


Ian.
 

Rob Pulham

Western Thunderer
Thanks for the heads up Ian,

It's something to be aware of. Thankfully those fitted to mine have rounded edges rather than sharp ones. I say thankfully, because I had the J6 chassis running on mine for two days at an exhibition in June without ill effects - I have just double checked after reading your post.
 

Ian@StEnochs

Western Thunderer
Thanks for the heads up Ian,

It's something to be aware of. Thankfully those fitted to mine have rounded edges rather than sharp ones. I say thankfully, because I had the J6 chassis running on mine for two days at an exhibition in June without ill effects - I have just double checked after reading your post.
Rob,

My RR is a Metalsmiths one. Like you I modified mine but opened it up to suit 33mm gauge!

Ian.
 

Dan Randall

Western Thunderer
Hi Rob

I have a HH chassis jig/rolling road too. The first time I used the rolling road was with a factory built DJH 03 diesel shunter and it was so heavy, the whole thing toppled over, as soon as I released my grip on the loco!

Luckily, I managed to catch the loco before it could fall onto my workbench, but it was a close and potentially expensive call.

I intend to attach a much wider base to the existing MDF base (extending under the rolling road), before I use it next!


Regards

Dan
 

3 LINK

Western Thunderer
Hi Rob

I have a HH chassis jig/rolling road too. The first time I used the rolling road was with a factory built DJH 03 diesel shunter and it was so heavy, the whole thing toppled over, as soon as I released my grip on the loco!

Luckily, I managed to catch the loco before it could fall onto my workbench, but it was a close and potentially expensive call.

I intend to attach a much wider base to the existing MDF base (extending under the rolling road), before I use it next!


Regards

Dan

Hi Dan,

I have fitted my HH jig with a piece of ply for exactly the same reason.

CAFD5391-F387-41AD-B313-306E0BA2E105.jpeg

Martyn.
 

Rob Pulham

Western Thunderer
I must admit it's on my things to do, although up to now I have just popped a weight on the back.
My problem is if I fit a bigger base, it may no longer fit where it usually lives. Finding an alternative storage spot may be a problem...
 
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