Neil Robinson
Registered
A relatively easy and inexpensive method from GSM
[h4]Posted by: fnrobinson Jun 3 2009, 08:19 PM[/h4] When I visited Fred (Dragon) on Sunday I was impressed by the amount of track he had acquired but concerned about the lack of cleanliness of the rail ends and fishplates. Track was being laid enthusiastically but I feared that when power was applied trouble would occur at many of the joints
A really good method of bonding track properly is detailed on http://www.girr.org/girr/tips/tips1/track_soldering_tips.html < Link To http://www.girr.org/girr/...ck_soldering_tips.html However I wanted to try a quick fix, minimum expenditure (on both tools and materials) and minimal preparation method.
IMHO there is little point in cleaning the rail ends without cleaning the fishplates. This means removing (sometimes awkward) and replacing (expensive) or cleaning (not easy) them. Using rail clamps at around £1.40 each isn?t an option as Fred?s layout will have several hundred joints!
Drilling the rail and using small nuts and bolts wouldn?t guarantee good electrical connection between bolt and hole in the rail and would risk fouling wheel flanges if the bolts were slightly long. Tapping the holes should resolve the connection issue, but tapping that many holes would be tedious especially with the care needed with such small taps and the potential problem with over long screws would remain.
I finally managed to waken a few of my brain cells and a web search revealed a supply of small stainless steel self-tapping screws. I chose the No 2 x 6.4mm pozi head countersunk type from http://www.modelfixings.co.uk/self_tapping_screws.htm < Link To http://www.modelfixings.c...elf_tapping_screws.htm This company is mail order only but their address is less than seven miles from Fred?s home.
So I decided to try the following method. Strip out a little wire from some mains cable, in my case the earth conductor from 2.5sq mm flat twin and earth. Any similar sized wire will do and using freshly stripped wire will ensure that it is clean. First twist one end using round nosed pliers, then kink the middle, put another twist around 15 to 20mm from the first, then cut where the excess wire crosses on this second twist. A final squeeze between a pair of pliers should ensure it lies flat on the workbench and looks like that in the photo. I decided on this shape so that the ends curve in the direction that the screws will tighten and the small kink in the middle should allow for any movement such as expansion.
Now drill a 2mm dia. hole into the rail through the fishplate at 45 degrees from the vertical some 7 to 10mm from the rail end at the point where the foot meets the web on the outside edge of the track. This means that any excess length will protrude through the bottom of the rail rather than the inside. Also drilling at 45 degrees on the outside edges of the rail is relatively easy with track that is laid. Next fix one wire link into one rail with a screw and then drill the hole for the other at the same angle as before using the link as a guide to position.
The self tapping nature of the screws should ensure good electrical connection between screw and rail and the countersunk head and clean wire should give good electrical connection between the screws and therefore the rails.
On test, with 1.2A flowing through the joints of the old uncleaned prototype in the picture, my multimeter detected a 2mV drop on the plain joint on the far side but none on the treated one on the nearer rail to the camera.
This method is my idea and, AFAIK, no one has published this method but I wouldn't be surprised if it has been tried before.
If anyone tries it, or has already done so or something similar I'd appreciate any feedback.
N.B. the wire link is not needed.
[size=14pt]See later postings
[/size]
[h4]Posted by: minimans Jun 3 2009, 10:42 PM[/h4] I've been doing this for years Neil and I found long ago that the wire is redundent as the fishplate performs the same function I now just use a dab of grease when screwing in the screw to stop it galling on the brass and as an anti oxident!
[h4]Posted by: fnrobinson Jun 3 2009, 08:19 PM[/h4] When I visited Fred (Dragon) on Sunday I was impressed by the amount of track he had acquired but concerned about the lack of cleanliness of the rail ends and fishplates. Track was being laid enthusiastically but I feared that when power was applied trouble would occur at many of the joints
A really good method of bonding track properly is detailed on http://www.girr.org/girr/tips/tips1/track_soldering_tips.html < Link To http://www.girr.org/girr/...ck_soldering_tips.html However I wanted to try a quick fix, minimum expenditure (on both tools and materials) and minimal preparation method.
IMHO there is little point in cleaning the rail ends without cleaning the fishplates. This means removing (sometimes awkward) and replacing (expensive) or cleaning (not easy) them. Using rail clamps at around £1.40 each isn?t an option as Fred?s layout will have several hundred joints!
I finally managed to waken a few of my brain cells and a web search revealed a supply of small stainless steel self-tapping screws. I chose the No 2 x 6.4mm pozi head countersunk type from http://www.modelfixings.co.uk/self_tapping_screws.htm < Link To http://www.modelfixings.c...elf_tapping_screws.htm This company is mail order only but their address is less than seven miles from Fred?s home.
So I decided to try the following method. Strip out a little wire from some mains cable, in my case the earth conductor from 2.5sq mm flat twin and earth. Any similar sized wire will do and using freshly stripped wire will ensure that it is clean. First twist one end using round nosed pliers, then kink the middle, put another twist around 15 to 20mm from the first, then cut where the excess wire crosses on this second twist. A final squeeze between a pair of pliers should ensure it lies flat on the workbench and looks like that in the photo. I decided on this shape so that the ends curve in the direction that the screws will tighten and the small kink in the middle should allow for any movement such as expansion.
Now drill a 2mm dia. hole into the rail through the fishplate at 45 degrees from the vertical some 7 to 10mm from the rail end at the point where the foot meets the web on the outside edge of the track. This means that any excess length will protrude through the bottom of the rail rather than the inside. Also drilling at 45 degrees on the outside edges of the rail is relatively easy with track that is laid. Next fix one wire link into one rail with a screw and then drill the hole for the other at the same angle as before using the link as a guide to position.
The self tapping nature of the screws should ensure good electrical connection between screw and rail and the countersunk head and clean wire should give good electrical connection between the screws and therefore the rails.
On test, with 1.2A flowing through the joints of the old uncleaned prototype in the picture, my multimeter detected a 2mV drop on the plain joint on the far side but none on the treated one on the nearer rail to the camera.
This method is my idea and, AFAIK, no one has published this method but I wouldn't be surprised if it has been tried before.
If anyone tries it, or has already done so or something similar I'd appreciate any feedback.
N.B. the wire link is not needed.
[size=14pt]See later postings
[/size]
[h4]Posted by: minimans Jun 3 2009, 10:42 PM[/h4] I've been doing this for years Neil and I found long ago that the wire is redundent as the fishplate performs the same function I now just use a dab of grease when screwing in the screw to stop it galling on the brass and as an anti oxident!
(read wet./moist)
