TR4 / 4a Control Plinth

[GreatOldOne]

Gents,

I've been drawing up in CAD the TR4 Switch / Control Plinth for @TR4Tony VC This is going well so far:

 

I've even begun to print the first prototypes:  (forgive the purple plastic - best to use the garish stuff on the first few whilst ironing out the kinks and getting the fitment right).

 

The holes are bob-on right now, but I'm tweaking the cut out for the crash pad, and I need to ensure fitment before I make any 'real' ones. Would anyone be interested in one? I can do them with or without the crash pad cut outs. They'd be printed in either PETG or ASA for UV resistance. 

Cheers

Jason

[BlueTR3A-5EKT]

That is a game changer for TR4 owners missing such an item.   Next requirement will be the aluminium fascia that has a dimpled effect.

 

[Chilliman]

Just fantastic....I suspect you will have a willing market opening up before you, well done & keep the projects coming....👍

[rcreweread]

Jason - I would definitely be interested in one depending on ultimate quality and price - I would want the crash pad profile cut out

Cheers Rich C-R

[TR graham2]

Looks great, but be aware the earlier crash pads where a different size to later remade ones , so you would be best to cut your own to size , I would be interested in one please .

graham

[RogerH]

It beats my mahogany version  

 

Roger

[TR4Tony VC]

17 hours ago, BlueTR3A-5EKT said:

That is a game changer for TR4 owners missing such an item.   Next requirement will be the aluminium fascia that has a dimpled effect.

 

The challenge is finding the aluminium sheet to make those …. I have the tooling now and have made steel versions with varying configurations including a ‘ashtray delete’ and ‘5th gauge hole’ versions and of course the standard pattern as used on most of the TR4’s produced except the early ones. 
 

If anyone can steer me on a source of custom produced sheet that could replicate the patterning please get in touch.

Regards

Tony 

[stuart]

4 minutes ago, TR4Tony VC said:

The challenge is finding the aluminium sheet to make those …. I have the tooling now and have made steel versions with varying configurations including a ‘ashtray delete’ and ‘5th gauge hole’ versions and of course the standard pattern as used on most of the TR4’s produced except the early ones. 
 

If anyone can steer me on a source of custom produced sheet that could replicate the patterning please get in touch.

Regards

Tony 

That dotty effect is also used on early E type facias and tunnel cover tops as well as the forward facing "B" post covers on earlier Healeys and then there is this for Astons https://astonparts247.com/product/db4-db5-db6-polka-dot-aluminium-sheet-695288/

Stuart.

[stuart]

I would be interest in one Jason for an early 61 TR4

Stuart.

[BlueTR3A-5EKT]

10 minutes ago, TR4Tony VC said:

The challenge is finding the aluminium sheet to make those …. I have the tooling now and have made steel versions with varying configurations including a ‘ashtray delete’ and ‘5th gauge hole’ versions and of course the standard pattern as used on most of the TR4’s produced except the early ones. 
 

If anyone can steer me on a source of custom produced sheet that could replicate the patterning please get in touch.

Regards

Tony 

In jewellery manufacture such patterning is rolled into the metal’s surface     Issue with doing that is the resultant curve.

Another method would be etching    Place a mash securely over the aluminium that has all the holes in it like a net curtain.   Spray on a product that will resist acid etching in the masked areas, Immerse in etching liquid and see what you get.    Then anodise to get a bright finish.

 

[GreatOldOne]

I’ve got two samples I’m working from… an injection moulded plastic item, and a pressed cardboard and vinyl one - both supplied by Tony. What I need to ensure a good fit is the radiuses of the crash pad. As I’m working from a copy and a slightly dog eared original cardboard one, what I have at the moment is an approximation. So if anyone can measure the crashpad and let me know I can amend the model.

as far as I can tell the forward most circular arc of the cut out is 12.7mm (1/2 inch). The lower arc is either straight or a very large radius, so,I’ve opted for straight right now. The upper arc has a radius of  70mm(ish)… but it’s difficult to measure when I’m using a chord of the circle work out the radius. I need 3 hands to hold the part, a straight edge and my calipers! 🤣

Edited October 16, 2025 by GreatOldOne

[TR4Tony VC]

10 hours ago, stuart said:

That dotty effect is also used on early E type facias and tunnel cover tops as well as the forward facing "B" post covers on earlier Healeys and then there is this for Astons https://astonparts247.com/product/db4-db5-db6-polka-dot-aluminium-sheet-695288/

Stuart.

£350 a sheet ! 

[TR4Tony VC]

10 hours ago, GreatOldOne said:

I’ve got two samples I’m working from… an injection moulded plastic item, and a pressed cardboard and vinyl one - both supplied by Tony. What I need to ensure a good fit is the radiuses of the crash pad. As I’m working from a copy and a slightly dog eared original cardboard one, what I have at the moment is an approximation. So if anyone can measure the crashpad and let me know I can amend the model.

as far as I can tell the forward most circular arc of the cut out is 12.7mm (1/2 inch). The lower arc is either straight or a very large radius, so,I’ve opted for straight right now. The upper arc has a radius of  70mm(ish)… but it’s difficult to measure when I’m using a chord of the circle work out the radius. I need 3 hands to hold the part, a straight edge and my calipers! 🤣

Both are original parts - the cardboard one is early, the plastic one late. I think the plastic one is pretty good, the cardboard one is a bit wobbly so I would have thought getting the plastic one (which fits the smaller crashpad) would mean the copy could be manually trimmed down to fit earlier cars ? 
 

[rcreweread]

Just now, TR4Tony VC said:

Both are original parts - the cardboard one is early, the plastic one late. I think the plastic one is pretty good, the cardboard one is a bit wobbly so I would have thought getting the plastic one (which fits the smaller crashpad) would mean the copy could be manually trimmed down to fit earlier cars ? 
 

I must say that I never realised the crash pads could be different - I've handled quite a few of these over the years and never noticed this. However the crash pads are foam filled beneath plastic covers so there is a bit of "give" if necessary or if the alternative is the problem, I found using the rubber seal trim which goes between an over rider and the bumper, works a treat as a finisher on the edge of the plinth and looks very professional!

Cheers Rich C-R

[GreatOldOne]

Ok, I’ll use the plastic one as a master then - as the part is only 2.5mm thick everywhere, it’s solid plastic rather than a solid perimeter and lattice infill as most 3d prints are. So it would be very easy to fettle as smaller cut out to fit a larger crashpad if needed.

[stuart]

2 hours ago, TR4Tony VC said:

£350 a sheet ! 

I know but it’s a big sheet so would do quite a few and it’s correct 😉

Stuart

[Jimgreen01]

Nice!

sign me up Jason. 

[GreatOldOne]

Diamond pattern fascia. I’m not sure I can get the diamonds any smaller and maintain their shape without just becoming blobs… and selecting ~1600 diamonds in CAD to emboss takes a while. 😉

Edited October 20, 2025 by GreatOldOne

[GreatOldOne]

V2 of the prototype without crash pad cutouts done, ready for test fit. On the printer right now is the version with the cutouts. @TR4Tony VC Ready for a try? 😎

Edited October 21, 2025 by GreatOldOne

[Charlie D]

Jason,

Whenever I see your photos it always amuses me to see that you are operating a 21st century 3D printer with a 1980's IBM model M keyboard.

Charlie.

[GreatOldOne]

It’s the Rolls Royce of keyboards. Weighs the same too. 

[TR4Tony VC]

Yes to a try ! I’ll bring a whole dash back over ? 

[GreatOldOne]

Sure - if you can. I have the crash pad cut out version all printed ready to try now as well. 

[GreatOldOne]

An attempt to get more diamonds…

[GreatOldOne]

Still purple, but in a state where I think these are ready. They’ve been test fitted to Tony’s dash and look ok - and I’ve managed to put a ‘leather’ texture on the surfaces. When it’s printed in black I think it’ll be a pretty good match to the original 

What colour was the fascia panel / insert? I printed it in black planting use the end of a roll up, but if it was silver I can see what colours are available. I doubt it could be printed to match a bright polished aluminium or similar, but something with a bit of shine should be doable with some of the ‘silk’ filaments out there.