Attaching Under Dash Trims to the Dashboard

[pharriso]

There has to be a batter way of attaching the under dash trims to the Dashboard than 4 self tapping screws into the side of the plywood Dashboard? Mine have been off a few times & the holes tend to strip etc.

Has anyone found a better way using a threaded insert for example?

My Dash measures 0.432" (3/8 + lots of varnish), what about something like this - https://www.amazon.com/uxcell-Threaded-Insert-Internal-Threads/dp/B07GKX5CN3/ref=sr_1_48?crid=1TIKVDLCKYXUK&keywords=wood+threaded+insert+10-24&qid=1655068069&sprefix=wood+threaded+insert%2Caps%2C143&sr=8-48

2022-06-12 17_10_38-uxcell Furniture Threaded Insert Nuts Zinc Alloy M4 Internal Threads 8mm Length .jpg (76.94 KiB) Viewed 1903 times

[fattogatto]

Too little material. You'd probably split the dash.

Industrial velcro?

[Lotusian]

Velcro works for me. Removed and replaced several times, and still firmly attached.
Ian

[mbell]

I've used some thing like those from the hw store but not very successfully. They tend to either not screw in well or come out of the dash rather that the screw coming out.

Might work ok if you can fit while the dash is out and for them in our something. Will need to be small ones as started not to split the dash.

[rjaxe]

I have just successfully refitted the under dash trim to my +2 using these threaded inserts. I found the most satisfactory way to avoid splitting the dash was a) clamp across the edge of the dash first b) use accurate pilot drill(trial if unsure) c)treat the insert as a tap and work it into the pilot hole progressively, otherwise as mentioned the dash will split. I put seven inserts in this way with the dash still in the car. Certainly a lot better than self tapping wood screws which just chew up the wood.
Richard

[steve lyle]

I’m using threaded insers as well. I got the smallest I could find at the local Ace he stiore. They take #4 screws, maybe #6, I’ll check. On 1 or two of them I had to epoxy the plies to get them to grip - the plywood was pretty torn up from the self tappers pulling out. As above, I clamped the edge after using a thin epoxy on the plies. I installed with the dash out.

I used then for the bonnet release bracket as well.

So far i’ve assembled/disassembled several times and they’re holding well with no issues

I’ll check sizes and see if I have a leftover to post a pic in the next day or two.

Definitely glad I made this change.

[pharriso]

Velcro works for me. Removed and replaced several times, and still firmly attached.
Ian

That's a good idea... let me investigate further...

I got the smallest I could find at the local Ace hardware store. They take #4 screws, maybe #6, I’ll check......I’ll check sizes and see if I have a leftover to post a pic in the next day or two.

Definitely glad I made this change.

Thanks Steve I'd appreciate the info...

Options are good...

[reb53]

They probably didn't exist years ago, or I'd never heard of them, so 30 years ago I made some of these and used them to hold the dashboard on.
The large chrome plated Philips headed screws bore down on them, rather than the varnished surface.
I made a basic tap to thread the dashboard and was able to thread my home made "stand offs" in and leave them about half a mil proud.
That they're not screwed right down is unnoticeable, and I have no cracks in the varnish, unlike the original.

Ralph.

[pharriso]

They probably didn't exist years ago, or I'd never heard of them, so 30 years ago I made some of these and used them to hold the dashboard on.
The large chrome plated Philips headed screws bore down on them, rather than the varnished surface.
I made a basic tap to thread the dashboard and was able to thread my home made "stand offs" in and leave them about half a mil proud.
That they're not screwed right down is unnoticeable, and I have no cracks in the varnish, unlike the original.

Ralph.

Ralph, I think you are talking about mounting the Dash to the body? I'm talking about fixing the under dash valences to the dash.

[Craven]

Matchstick in the hole works pretty well, the deluxe version would be a raw plug, fibre type,
there is also fibre filled power packing material available.

[pharriso]

Matchstick in the hole works pretty well, the deluxe version would be a raw plug, fibre type,
there is also fibre filled power packing material available.

I've tried a rawlplug... just pulls out...
Thx for the suggestions..

[USA64]

How about a thin metal right-angle bracket. That would allow the bracket to be secured in the proper orientation (screws into back face of plywood and in shear). The valence could then be secured with sheet metal screws with, perhaps, a bit of silicone for damping.

[wobblyweb]

What a great idea, I have some 3mm rivnuts which will probably fit the screw holes in the dash and epoxy in place.
I have never been happy with the fit of the trims.

[steve lyle]

Here's the inserts I used. They take a #6 machine screw, 32 tpi. Body diameter is .216".

In the first picture, the smaller insert is the one I eventually used, sourced from Ace HW. The larger one is also a #6, from Woodcraft. Too large for my dash thickness.

Pics 2 & 3 are of the bin at my local Ace. The inserts were $2.33 each.

Hope this helps. If you want to go this route, and can't get them locally, I can send them to you.

Regards,
Steve

[lotusfan]

These ideas of screwing inserts into the edge of the dash are fraught with difficulty and the danger of breaking through. USA64 has suggested metal brackets. Can I suggest glueing some strips of wood to the rear face of the dash to effectively double the thickness locally. This would then allow inserts to be used with much less chance of damage.