Jump to content
Image restoration from pre-May 2021 continues and may take an indefinite period of time.

Gibson 00 chassis conundrum


Guest Max Stafford

Recommended Posts

Guest Max Stafford

I'm building a DJH Caley Jumbo. Being a little underwhelmed with the chassis supplied, I ordered some Gibson frames and 00 spacers. The DJH frames were very wide with virtually no clearance between the wheel backs and the frames. The Gibson frames, not much narrower are an improvement, but there's still not much more than a fag paper between the wheels and frames. As I intend to DCC the loco, this is of some concern due to the virtual guarantee of arcing over the minimal gap. There isn't enough clear axle length to apply spacing washers. Is there any kind of precaution I can take to eliminate the risk of shorting, such as putting some kind of film over the frames?

 

Dave.

Link to post
Share on other sites

For one, what radius are you hoping to get the loco to go round ? As most loco's need some side play. I am not familiar with those spacers but can you not reduce the spacer width? IMO the easy route would be the spacers actually now I think about it your only route. Unless you go EM or P4 B).

 

Martyn.

Link to post
Share on other sites

Guest Max Stafford

My suspicions are confirmed. I'm just not happy about the lack of clearance in 00. I think I may have to equip this one with EM axles and send it to Culreoch...!

 

Dave.

Link to post
Share on other sites

Alan Gibson milled frames are a bit on the chunky side. You could coat them with tissue paper perhaps stuck down with (or soaked in) Klear, Izal might be the best if it's still available. No chance of getting a few thou off the spacers?

Link to post
Share on other sites

Could you use the milled frames as a template to cut out thinner frames?

Providing your wheels are not scraping on the frames, a few coats of primer and paint allowed to harden properly should prevent arcing.

 

Gordon A

Bristol

Link to post
Share on other sites

Guest Max Stafford

All good ideas thanks. I'm a little disappointed that the Gibson frames were so thick. I ordered them because I had exactly the same problem with the DJH frames. I've already added the supports for the brake hangers so I might as well just do this one with EM axles.

 

Dave.

Link to post
Share on other sites

I may be out to lunch here, but if you were using Comet (or similar) etched L spacers, you could file them back until you get the clearance you need. Are you sure the spacer is actually 00?

 

John

Link to post
Share on other sites

Good morning to all steam fans

I have used Gibson frames for several locos. I found that Gibson frames with Gibson hornblocks a no-no for OO. I use Comet OO spacers and Comet hornblocks. I sometimes file away the slight boss that the hornblocks come with, and have had no trouble with wheels shorting on the frames. A Comet or High Level gearbox will fit between the frames.

However, one piece coupling rods need to be replaced by hinged (is that the right description)rods. Gibson do many varities of coupling rods and the universal rods are available where there are no prototype rods. The universal rods are a fit fiddly to make up, but the result is worth the trouble.

Keep firing

Earlswood Nob

Link to post
Share on other sites

Guest Max Stafford

Thanks. It looks like I may need to use Comet spacers then. Fortunately, I have some going spare. The Gibson ones are 00 - that's what I specified and that's what they gave me. I thik it's down to the thickness of the frames which in any case where supplied rigid at my request. I'm nowhere near good enough at this to be adding such refinements as springing yet! :)

It's clear that where thicker grade frames are involved, some modification is going to be required to the spacer arrangements in future. I do have a spare set of Jumbo frames, so rather than mess about unsoldering everything, I think I'll assemble the second set with narrower spacers and use the current set up rigged for EM. This will allow me to swap the underpinnings for exhibitions when the loco will be able to make guest appearances on Culreoch. With an alternative tender of course - when you run into a small crisis like this, it makes life better if you view it as an opportunity than as an obstacle! ;)

 

Dave.

Link to post
Share on other sites

....clear that where thicker grade frames are involved, some modification is going to be required to the spacer arrangements in future....

 

Only logical, after all. I successfully used EM spacers with DJH armour-plated frames years ago on their BR Standard 5 to get S4 overall width.

Link to post
Share on other sites

Guest Max Stafford

Well, after wasting an afternoon trying to mount the spacers on top of the frames rather than inside, I'm calling it a day with this one. There's no guarantee that the spacers will be square when reduced either. Life's too short and I've plenty other stuff to be getting on with, so this kit's going back into the cupboard until somebody designs a chassis for it that's fit for purpose. <_<

 

Dave.

Link to post
Share on other sites

Hi All,

The Gibson frames should be from 0.6mm brass, which is 1.8" at 4mm to the ft. This isn't so far off the prototype frame thickness. So if your building in P4 or EM and running prototypical curves (or up and down a plank) you'd probably be quite happy. On the otherhand if the Gibson spacers were narrower you could be really struggling to find a gearbox narrow enough, perhaps gibson should stock all two hundred and eighty odd frames in two thicknesses and have two widths of OO spacers :). If you want to go around unprototypically tight bends then you need an unprototypical chassis design.

Faced with your set of circumstances I'd probably assemble the chassis and draw file each side down to get a little extra clearance. Nickel chassis are generally made from 0.018", 0.6mm equates to 0.024" so you could loose 0.006" each side, giving you 0.3mm extra, more if your feeling brave and take it down further. It isn't a lot but might help

 

 

Colin

Link to post
Share on other sites

Number one, DCC voltages simply do not arc, (far too low), it is a short that's the occurrence when it sparks, an arc occurs through air without metal to metal contact, and with DCC voltage levels is next to impossible.

 

Number two, just thin the spacers a bit, and solder up as usual, a clearance of .5mm per side should be ample for reasonable curves say 5 foot, (no set track). You may have to thin the gearbox as well by the same amount if it is tight. If a chassis is to run around very tight set track curves it may be best to have flangeless centre wheels, then the bigger clearances are not needed.

 

If the wheels short to the frame as they turn they must be running out of true too much, it should have no visible side to side movement on any wheelset, driver or bogie.

 

Stephen.

Link to post
Share on other sites

Guest Max Stafford

Thanks for the illumination Bertie. I'm no expert in electrical terminology! The layout (as yet unbuilt will have 3' radius as an absolute minimum. Before I brought on the Gibson frames, I was utterly amazed at the width of the DJH frames which would have stretched P4 clearances if the truth were known! To be honest, squareness of the chassis is more important than any other factor in my kitbuilding at the moment which is why I'm uncomfortable with trimming the spacers down.

Ah well, we'll see what happens.

 

Dave.

Link to post
Share on other sites

Stephen!!! - 5 foot is only "reasonable". I'd say that's pretty generous (in layout room terms if you're going through 90 degrees).

 

Scaling down plate sizes doesn't work in assesing whether a chassis is right for a 4mm model, it won't flex the same and we do have a motor/gearbox to fit. 18 thou is thin, but fine for our purposes if well supported, 15 thou may be a possibility too. Those DJH and Gibson are about twice that.

Link to post
Share on other sites

Archived

This topic is now archived and is closed to further replies.

×
×
  • Create New...