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DC Crew
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Discussion Starter #1
I'm putting in the rollbar on Saturday (then removing it to have it powdercoated).

I have to drill 16 holes into the frame, four at each corner.

1) Can anyone recommend a drill bit type to have the best results?

2_ I will be using grade-8 bolts.... after drilling the hole... how do I "thread" the hole?

Also, are there any tricks to get great results?

~Patrick:lookinup:
 

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DC Pit Crew
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you have to use a "Tap" or "Die", i can't remember which one is wich but i think its Tap, to thread the holes after they have been drilled....you should be able to find them at a hardware store
 

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El Teafive
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Patrick96LT4 said:
I'm putting in the rollbar on Saturday (then removing it to have it powdercoated).

I have to drill 16 holes into the frame, four at each corner.

1) Can anyone recommend a drill bit type to have the best results?

2_ I will be using grade-8 bolts.... after drilling the hole... how do I "thread" the hole?

Also, are there any tricks to get great results?

~Patrick:lookinup:
how thick it the frame, meaning how much bite would get from threading.


What size bolts will you be using? I got some Nutserts from Dave cooper to install my OEM cross brace on my coupe, basically you drill the hole, insert and tighten the nutsert and you now have decent threads. I have th eemaila nd a pic at home of them.

As for a drill bit, a carbide tipped one will be best, you may need a bit of cutting oil and a drill with decent power.

As for Bolts, if they will be visible you should get the ARP stainles bolts and I think they are stronger the the Hardware stores grade 8
 

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DC Crew
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Discussion Starter #6
Re: Re: What drill bit? How do I thread a hole?

I'd like to look into the "Dave Cooper" sleaves.

Any place around town I can get those at? Napa?
 

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DC Crew
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Discussion Starter #8

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2 pieces of tapping advice: GO SLOW and straight-lol
If the tap feels like it dosen't want to go anymore or gets tight don't force it, back it out. Like Jeff said use some tapping or machine oil, it helps quite a bit.

I think you're going to need some type of nuts though. I doubt there is going to be enough metal there to tap.
Do you know what size bolts you're using ?
for example a 3/8"-16 bolt has 16 threads per inch. That means one thread every 1/16 (.062"). If you're tapping into 1/8" (.125) material that only gives you 2 threads, 4 if you're going into .25" thick material. Even a 1/4"-20 bolt would only give you 2-1/2 threads in .125 thk. material. My guess is you're going to need to be tapping into atleast .25" material to get any kind of decent thread engagement.
I have a chart at work which gives minimum thread engagement lengths I can look it up if you want. I forget what the rule of thumb is, you'd think I remember this **** since it's what I do for a living. -lol
I'd think the safe route is some type of nuts like Jeff suggested.
 

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DC Crew
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Discussion Starter #10
I haven't started working on the car yet..... but how do I get nuts below the bolts? I don't even know if I have access to the rear of the spots.

Also, Arnie had the bar bolted in, and it comes with bolt holes.... you'd think it'd be ok...

I'd guess the structural material is 1/4 inch or greater, but I just don't know until I start...

:huh:
 

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are the holes in the bar threaded ?
What size bolts are you using ?
You need advice from someone who has installed one of these before -lol

just weld the damn thing in :D
 

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Patrick96LT4 said:

I'd guess the structural material is 1/4 inch or greater, but I just don't know until I start...

:huh:
1/4 inch is pretty hefty:surprised I'd say the frame wall thickness is between 090 and 125. Unless those areas are overlapping welded joint seams, then you could have 1/4 inch together.

What is the diameter of the bolt holes? The usual rule is bolt thread depth = 1 1/2 times thread diameter.
 

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DC Crew
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Discussion Starter #13
biltogo said:
1/4 inch is pretty hefty:surprised I'd say the frame wall thickness is between 090 and 125. Unless those areas are overlapping welded joint seams, then you could have 1/4 inch together.

What is the diameter of the bolt holes? The usual rule is bolt thread depth = 1 1/2 times thread diameter.
The holes look like 1/2 inch... and the holes are not threaded.
 

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I'm thinking there has to be a nut and washer behind there. I'm trying to imagine getting in there.:huh: I should have the 95 back up on ramps this weekend, and I'll look to see if I can offer any real help.
 

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Patrick,
A cobalt bit should work fine with some thread cutting oil. Should all be available at any hardware store or Menard's or Lowes or Home depot. You could get a nutsert tool at these home improvement stores. I know the one I have will go to at least a 1/4 " thread insert. This tool looks like a pop rivet gun with a special head on it for the insert.
 

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DC Crew
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Discussion Starter #16
I drilled the holes already with a 29/64" drill bit, and I bought a Plug style Tap for fine threads. I also bought some grade-8 bolts to fit in.

1) What is a Nut-sert?

2) The bar is in, and I've cut away the fiberglass (I'm proud of the workmanship! I took my time).

3) I've drilled the holes. But, I think there should be a nut on the bottom but there is clearly no way to do that since the steel frame is boxed and has no rear access.

Help?
 

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I looked at my 95. Man, I'm not sure I'm looking at the right place. I can't see enough without taking things apart.
 

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Hi :buhbye: :cool:
To answer the nutsert question. It is a piece of steel or aluminum with threads inside. A special tool that looks like a pop rivet gun is used to set them. You drill a hole stick in the insert squeeze the handle and it like rivets the insert in the hole. Home improvement stores carry them in the pop rivet section. The only draw back is I think they are limited to 1/4 in. thread. I have one here let me look. Yip mine just goes to 1/4.
 

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To answer the nutsert question. It is a piece of steel or aluminum with threads inside.
Personally, I wouldn't use nut serts for holding a 4 roll bar in place in a car. You want a seriously beefy mounting location
for your bar. Most of the bars I have seen mounted usually have
at least a plate welded to the frame and then either the plate on the roll bar is welded to this plate or bolted to the welded plate on the frame for ease of removal. What did your roll bar manufacturer recommend?
 
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