Dashboard fun

[Al_C]

Rather than continue on hijacking an old thread, I started a new one. (Please contain your excitement.) As a point of reference, here's the old one: http://thefactoryfiveforum.com/showt...h-installation

To pick up where we left off, the challenge is to get the right size hole for the speedo and tach. These are "vintage" gauges. Keep in mind that I'm covering the aluminum with a wood veneer so there won't be the vinyl cushion folded into the opening. Here's the problem:



This is what the pre-cut dash looks like (as if you never saw this before...)



You can see that the gauge is bigger than the pre-cut hole, but not as big as the alternate cuts on the dash.



The pre-cut hole is 3 1/2 inches.



The cardboard cutout in the box is 3 7/8. That should be the right size for the hole in the dash. Maybe a little bigger, but not much. John (Phileas_fogg) suggests 3.9, and that's pretty darn close.

OK, nothing new so far. Here's the real issue. Left to my own devices, I'd probably work on the opening with the dremel tool, but there's probably a better way that someone else has tried. John (Phileas_fogg) suggested a hole cutter in the other thread, but the setup (i.e. centering) for that would be problematic given that I already have an opening, and I'm only trying to expand it. The hole cutter would be ideal for a blank dash.

Your thoughts? My goal is to get the cut right on the first try. Thanks for your input!

[Norm B]

If you want to use it holesaw then clamp a piece of 3/4 plywood behind the hole to act as a guide for the centering bit. I would predill the centering hole in the plywood. Centre this hole where you want the new opening to be and cut the hole as normal. To limit the chance of the centering bit wandering by cutting the plywood you could replace the bit with a steel rod.

[JIMOCO]

I don't understand the problem. I have the ffr vintage gauges and only needed to break away the smaller hole. My gauge fit the hole without any other modifications. Are your gauges different than the ffr vintage kit? If you snip between the points that are not scribed you can bend the tab back and forth to remove it.

[Gumball]

Al,

If you have to open the hole up a little, use a dremel with the 1/2" or larger barrel sander tool. That's what I used on mine and they work great. You'll go through a bunch of them, but they allow for good control and as long as you keep moving around the circumference, you'll keep the hole's shape.

[Al_C]

I don't understand the problem. I have the ffr vintage gauges and only needed to break away the smaller hole. My gauge fit the hole without any other modifications. Are your gauges different than the ffr vintage kit? If you snip between the points that are not scribed you can bend the tab back and forth to remove it.

Jimoco, The problem is that if I open the hole up by breaking away the pieces, the hole is too big. Since I won't have the vinyl folded in the hole, there will most likely be too much play. That's why I want an opening somewhere between the "small" hole and the larger one. The veneer will be cut to the same size as the hole; there is no padding or buffer between the side of the gauge and the edge of the hole.

[JIMOCO]

Ok. Now I understand. I thought that after enlarging the hole you still could not get it to fit. Sorry for the confusion.

[Boydster]

How about some type of shim, or spacer, around the gauge to take up the difference with the big hole? It would only have to be 1/8" thick... like a centering ring.

[myjones]

If you want to use it holesaw then clamp a piece of 3/4 plywood behind the hole to act as a guide for the centering bit. I would predill the centering hole in the plywood. Centre this hole where you want the new opening to be and cut the hole as normal. To limit the chance of the centering bit wandering by cutting the plywood you could replace the bit with a steel rod.

That approach can still let the hole wander a bit because the surface area of the teeth on the aluminum has more leverage than the pilot bit on the wood. It's a lot safer
to drill the wood first with the hole saw and then clamp the plywood on the front of the dash exactly where you want the hole to be cut, much less potential for it to
wander because of the increased area of the wood surface to the holesaw. HTH
DB

[rich grsc]

Just breakout the dash, it's only going to be 1/8" too large. Use the veneer to get the hole size and location you want. The threaded nut on the gauge will clamp onto the aluminum dash. You are way over thinking this and seeing problems that don't exist.

[Jeff Kleiner]

As I was reading I had the exact same thought as Rich; let the veneer establish your final hole size and don't worry that the aluminum behind it is slightly oversize.

Jeff

[Railroad]

Wrap the outside of the gauge housing with something like electrical tape. There may be better options for the wrap, but this method will stay consistent and center the gauge too.

[rich grsc]

Wrap the outside of the gauge housing with something like electrical tape. There may be better options for the wrap, but this method will stay consistent and center the gauge too.

Except then you can't tighten the nut on the gauge.????

[johnnybgoode]

It's very easy to enlarge the size of the holes with a large drum sander in a drill press. I used a 3" drum for the tach and Speedo holes and a 1 1/2" for the smaller gauges. Set the drill press for high speed, put the dash hole you want to enlarge through the sander and then turn on the DP making sure the sander is not touching the dash or it may pull it out of your hands. If you slowly roll the inside of hole around the drum sander in the opposite direction to it's rotation you will feel it start to cut. Continue to roll the sander around the hole in a hula hoop motion, don't let it dig in or sit in any one spot. Once you get used to it you can probably take off 1/16" in 30-60 seconds so stop and check your work/test fit your gauge. Probably a good idea to wear some heavy gloves as well.

I used this same method and sanders to enlarge the speaker holes in the 37 for some new audio. http://www.ffcars.com/forums/49-othe...o-upgrade.html Works great on fiberglass. Just keep a vacuum handy for the dust. Scott

[Papa]

What about opening up the hole to the larger size and then slipping a rubber o-ring like an x-profile style (https://www.mcmaster.com/#rubber-o-rings/=16xda0j) around the gauge or inside the opening? It seems that could fill any small void (essentially taking the place of the dash vinyl) and also stabilize the gauge and prevent it from moving around due to vibration.

Another option would be to cut the inner ring perpendicular to the pre-cut larger opening leaving five tabs that you could trim to the desired length to keep the gauge centered in the opening.

[phileas_fogg]

Your veneer is likely less than 1/32" thick, correct?

I would use an oscillating drum sander. Lots of woodworkers out there have them. 80 grit will get you where you want to be in no time.

You can also use a sanding bit in a drill press, but you'll have to change the height of the dash a bunch of times as you burn through the sanding material.

I would NOT use a hole cutter; as stated previously it would be very difficult to control.

Cheers,


John

[Al_C]

Great input! Thanks! Personally, I like the o-ring idea best. I had that in the back of my mind, but didn't know where I could find one the right size. Looks like Papa found it! Much, much easier. And, as Rich Grsc alluded, we don't want to make this anymore complicated than it already is.

[carlewms]

I did not use the standard hole saw to cut the large holes ... here is a link to the build thread and the information is in post 155.