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Author Topic: Best drillbit?
Mark McCallister Verified Driver Made Donation to Website
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Ok, I know this was covered in jr. high shop class...but apparently I missed that day. Car is getting annual tech this afternoon, and the one thing I need to finish (that I know of so far!) to get it GCR legal is inspection holes in the rollcage. Last night I flattened the end of two supposed metal-cutting drillbits attempting to drill the first hole. And the all I got was a bit of a dimple where I was trying to drill for my efforts. What drillbit/technique works best for this?

Thanks..

disquek Verified Driver Made Donation to Website
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Any HSS drill bit should have no problem making the required holes in the cage. Be sure not to drill into a weld. Drill into the tube only. Turn the drill at a moderate pace and use a light pressure. Sounds like a trip to The Orange Box for a new drill index is in order.

That said, tech usually has a drill for just this purpose and then they can put the holes where they want them.

Good luck.

-Kyle

spdmonkey Verified Driver Made Donation to Website
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I'll second what Kyle said. Tech has always insisted on drilling their own holes on every car i've built. Let them do it. If you must do it yourself, buy some good titanium coated bits or any high speed steel bits and a squirt or 2 of wd40 as you drill will help.

db

Mark McCallister Verified Driver Made Donation to Website
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Thanks Kyle and db... I'll get a six pack of bits this time on the way home. Maybe I already dulled those two bits on something and didn't realize it.

I love the way the GCR says the holes should be in a non-critical area. I was trying to rationalize just exactly which area of a roll cage is non-critical.. [Smile] As you say the weld are definitely THE most critical, but after that...

That's not a bad idea, I will get the bits and have the them tell me where to drill. I like that. [Smile]

Greg Bush Verified Driver
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Another tip,

Make sure the drill is going the right direction.

Not poking fun at you but I've seen it before.....

Greg

Willie the Tard Verified Driver
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build your cage out of PVC like I did -- very easy to drill

--------------------
William Keeling a.k.a. Willie the Tard

Mark McCallister Verified Driver Made Donation to Website
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Alrighty, new drill bit did the trick. Inspection passed, got my logbook, life is good! [Big Grin]

springfielddyno Verified Driver
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quote:
Originally posted by Mark McCallister:

I love the way the GCR says the holes should be in a non-critical area. I was trying to rationalize just exactly which area of a roll cage is non-critical.. [Smile] As you say the weld are definitely THE most critical, but after that...
[Smile]

without going into FEA, passenger side perhaps, not near a weld or bend... just my .02...

--------------------
Regards,
Sam H.
www.springfielddyno.com

Blake Clements Verified Driver Series Champ
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quote:
Originally posted by Willie the Tard:
build your cage out of PVC like I did -- very easy to drill

You laugh, but I knew someone that did that in an SS Camaro so they could keep running at the drag strip because their car was too fast. [Big Grin]

--------------------
Blake Clements

PhillipsRacePrep/SP Induction Systems/East Street Racing/MiataCage.com/Carbotech/WBR Graphics

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springfielddyno Verified Driver
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pvc, sch40 or sch80? might be able to save some $$ over DOM... kinda makes me wonder about TX [Wink]

--------------------
Regards,
Sam H.
www.springfielddyno.com

Lance Snyder Made Donation to Website
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quote:
Originally posted by Blake Clements:
quote:
Originally posted by Willie the Tard:
build your cage out of PVC like I did -- very easy to drill

You laugh, but I knew someone that did that in an SS Camaro so they could keep running at the drag strip because their car was too fast. [Big Grin]
I've also heard of that in the old IMSA days instead it was exhaust tubing.

--------------------
All this has happened before, and will happen again

jigou Verified Driver
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As for where to drill the holes, aside from having Sam do that FEA, take your drill and bits along when you get the inspection and let the inspector tell you where he/she would like the holes. Sure, they'll probably accept wherever you've drilled them if you do it ahead of time...

Jarrod

--------------------
http://www.plainoldgas.com

springfielddyno Verified Driver
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for the record, I'm not doing any FEA on cages [Wink]

--------------------
Regards,
Sam H.
www.springfielddyno.com

   

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