Society BFJ switch blade file suitability for FB rail

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murphaph

Society BFJ switch blade file suitability for FB rail

Postby murphaph » Mon Jan 11, 2021 4:06 pm

Hi all,
First real post here. I'm wondering as a total newcomer to all this if the society's BFJ filing jig is suitable for FB rail at all? From the picture I would have thought no as there doesn't appear to be a slot for the base of the FB to sit into. Is it only suitable for BH rail maybe?

I'm looking to mostly model Irish 5'3" using FB rail (code 75-82).

Thanks for any help you can offer.

Phil

Terry Bendall
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Re: Society BFJ switch blade file suitability for FB rail

Postby Terry Bendall » Tue Jan 12, 2021 9:46 am

murphaph wrote: Is it only suitable for BH rail maybe?


That is what they were designed for. That said the vee filing jig will work for FB rail if the base of the rail is at the top. The blade filing jig will not work for FB rail but it would be possible to use a piece of wood to hold the rail if a saw cut is made to take the foot. There would of course not be a guide for the taper.

On the kits previously available from Colin Criag the stock rails has a fairly substantial amount of thinning of the straight and curved stock rails to make a seating for the blades. Colin used to mill these but it might be possible to file them with care.

About three years ago Colin supplied me with the following information about the sizes of FB rail available at that time.

Height Foot Head
Real world rail BS110, BS113A 2.08 1.83 0.91

Peco Code 82 2.06 1.74 0.88 No longer made
P4 Track code 82 N.Silver 2.08 1.78 0.93 Not available
P4 Track code 82 Steel 2.08 1.76 0.91 Still listed
C&L code 82 2.08 1.73 0.80 Not available
EM gauge Soc Code 83 2.11 1.87 0.91 Available from EMGS

The Code is the height of the rail in thousandths of an inch
All the code 82 samples had a foot which is slightly undersized. Otherwise the dimensions are accurate, with the exception of original C&L code 82 which also had an undersize head.
This undersized head creates a problem with suitable track gauges.
The Code 83 EMGS is slightly too high, but really not an issue. The foot is slightly oversize but, as the web of the rail is grossly oversized, this is not a visual issue.

The supply situation, and perhaps the sizes may have changed since the information was provided.

Terry Bendall

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grovenor-2685
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Re: Society BFJ switch blade file suitability for FB rail

Postby grovenor-2685 » Tue Jan 12, 2021 12:37 pm

Blade filing jigs are a luxury rather than a neccessity, I have always done a TErry suggests and used a sawcut in a ply or MDF offcut to hold oneside of the foot while the other side is filed down.. The planing length is shown on the Templot diagrams and easily marked on the offcut as a filing guide.
There should not be a recess in the stock rail head but you do need a recess in the stockrail foot so that the blade can close against the stock rail, More modern switch designs do plane away some of the underside of the switch foot so it can go over the stock rail foot but that's a difficult filing excercise not worth the effort in my book, just model the older design.
Of course the very latest designs use a special low height rail section for the blades to avoid this problem but no one, so far as I know , has had any such special sections drawn.
Regards
Keith
Grovenor Sidings

murphaph

Re: Society BFJ switch blade file suitability for FB rail

Postby murphaph » Tue Jan 12, 2021 2:15 pm

Thanks a lot chaps. That clears that up. I had seen the described "offcut jig" as described in Iain Rice's Pragmatic PCB track book. I will need to mass produce a lot of track for the hidden and staging areas of my layout using this method to gain a foothold (pardon the pun) in the craft.

I may still order a blade jig for BH rail and use this in the fiddle yards to hopefully deliver a more consistent, if not necessarily better blade.

I had originally assumed that FB would be easier than FB to solder to PCB sleepers because well, it's flat. Terry told me in my intro thread however that BH rail is easier to begin with so that changes my plans a bit naturally.


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