How to profile a bum shaped depression in a 5″G drivers tip-up seat

[GreensandsParticipant @greensands]

Here is one for the rivet counters. I would like to be able to fit a couple of tip-up driver/fireman's seats to a 5" gauge loco from oak measuring typically 15" square by 0.1" thick but the problem is that in order to make it look somewhat less slab like I would like to be able to create the bum shaped depression in the centre of the seat. Does anyone have any ideas on just how this might be achieved in 5" gauge? The attached photo shows an example of a full size driver's seat taken at one of our preserved railways.

[GreensandsParticipant @greensands]

[JasonBModerator @jasonb]

Carve it out with a gouge or some form of disc/drum sander. I assume it's 1.5" square not 15"

It's an odd shaped bum depression as most people have two buttocks, I wonder if the metal one shown has just become dented over tine by being used as a step

[GreensandsParticipant @greensands]

Jason – Size of seat in 5" gauge should read 15/11.8 = 1.25" square.

[Mick B1Participant @mickb1]

The traditional tool is a travisher. You can get them in various sizes but I shouldn't think that small – assuming it's a scale seat rather than one for a full-size driver.

Could you use Miliput or suchlike putty with a thumb-pressed depression?

[DalboyParticipant @dalboy]

It does seem strange that a seat would have one central depression as in the picture as many wooden seats have a U shape depression. And I doubt if standing on a wooden seat would dent it like metal Jason.

Maybe designed like that so they would not want to sit for long. To recreate this a simple dremel type drum sander will aid in making it because of the scale of it but don't forget the bolt in the middle.

Or even a carving Scorp

Edited By Derek Lane on 06/12/2021 18:52:22

[old martParticipant @oldmart]

Jason, on my screen, the seat shows woodgrain and looks to me like three pieces. To make a replica, I would use a dremel size flap wheel.

[mike TParticipant @miket56243]

I would go for timber with a finer grain then oak, otherwise it will lookout of scale, unless you intend to paint them.

[old martParticipant @oldmart]

That bolt in the middle brings to mind a story about the original jeans made by Levi Strauss which had a rivit in the crotch until complaints were heard from cowboys who got burned sitting around their traditional camp fires.

[JasonBModerator @jasonb]

Sorry, I can see the grain now I have enlarged it, silvery colour made me think it was metal.

[Nigel Graham 2Participant @nigelgraham2]

I'd establish first if the full-size seat for the particular loco or its related classes, had such hollows. (I am not convinced by whatever happened to the one in the photo). However, assuming so, by comparison with other furniture generally the mouldings would be so shallow that very careful sanding, perhaps assisted first with a rasp, ought be sufficient to represent them.

I've never had cause to measure furniture to that detail but generally, situpon hollows don't look much more than about 1/4 " or so deep.

===

This does remind me though of a friend who as a Senior Medical Lecturer appears to collect some remarkably naive students, and recounted to me one once asked, "Do women have buttocks? "

My friend solemnly assured him they do.

Then told me she asked him, "What else do you think we sit on? "

[Martin KyteParticipant @martinkyte99762]

You need one of these.

**LINK**

Trouble is they are are out of stock at the moment.

However now you have got the idea you could make one.

regards Martin

Edited By Martin Kyte on 06/12/2021 20:28:25

[Rob McSweeneyParticipant @robmcsweeney81205]

A nice sharp bullnose end mill ought to do the job

[Robert BParticipant @robertb]

The depression isn't very deep. Some 80 and 120, possibly 180, grit paper glues to stick will make that quite quickly and keep the non engineered shape. The seat of pants over a few years will make this or standing on it with hob nails. Windsor chair makes have special tools but on this scale they are not needed. Look for a finer grain. Oak can be distinctly coa

rse and not in keeping. Should it have an oil and coal dust patina?

Rob

[Speedy Builder5Participant @speedybuilder5]

angle grinder fitted with sanding disc. Test correct depth of the scallops by putting marking blue on buttocks and sand away the high spots (on the seat, not on the butt….).

Bob

[Michael GilliganParticipant @michaelgilligan61133]

These are bigger than the scale you need … but the video shows seat shaping:

**LINK**

MichaelG.

.

Edit: __ Here is his tool for the full-size chair seats

Edited By Michael Gilligan on 07/12/2021 08:30:16

[larry phelan 1Participant @larryphelan1]

As Mrs Beeton might advise, "First catch your bum"

[GreensandsParticipant @greensands]

Have attached a photo showing a second example of a full sized drivers' seat with an alternative form of profiling which would be easier to replicate in miniature

[Ady1Participant @ady1]

I suppose a bum shaped grinding wheel would generate a bum shape

A foam backed roll of sandpaper?

Edited By Ady1 on 07/12/2021 09:44:55

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Greensands on 07/12/2021 09:36:59:

Have attached a photo showing a second example of a full sized drivers' seat with an alternative form of profiling which …

… looks worryingly like a shallow catchment vessel

Don’t brake too hard !

MichaelG.

[DalboyParticipant @dalboy]

I think that sometimes we overlook the obvious solution and that is put it in the lathe and turn it with hand chiselsas a woodturner would do this.

[Michael GilliganParticipant @michaelgilligan61133]

In ‘our’ defence, Derek … turning a depression, using the lathe, only becomes relevant when you are no longer trying to produce a ‘bum-shaped’ seat.

MichaelG.

[pgk pgkParticipant @pgkpgk17461]

Not relevant to a model engine seat but perhaps of interest:

I recall an old technique for making a seat by lowering bum into a bucket of wet cement, then making a negative from that and laminating between the profiles.
For the ultimate rowing luxury, a bespoke sliding seat such as here
Back in my racing days, I found one comfortable seat and pinched it and carried it with me for use in whatever boat I was assigned.,,, still have it among my trophies.

pgk

[Nigel Graham 2Participant @nigelgraham2]

The sagacity of this forum knows no bounds….

Learned discussions on the mysteries of CAD/CAM equipment, programmes and use thereof;

Advice on identifying and overhauling vintage machine-tools;

The principles and construction of valve-gears and injectors;

Photographing the cosmos;

etc., etc.;

and now, notwithstanding that I do in fact greatly respect and admire detailing to prototype –

– detailing to the extent of 1:12 scale botts on seats that in 1:1 scale were probably rarely if ever built to such luxury!

The enginemen of old are said to have called travelling in the coaches as "on the cushions" …

[Author]

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