Give me some advice on how to drill the frame

[gearbox]

Help me, y'alls. You're my only hope.
I have a pair of sliders that require drilling (8) 1/2" holes and (4) 3/8" holes in my '06 Tacoma AC frame.
I've heard that it is best to drill progressively larger holes and that several bits will be broken.

What to do? 1/2" bits are expensive!
All I know is that I want to use a center punch to keep the holes from being Bubba'd.

Also, should I give the holes a shot of primer and paint? The 3/8" are self-tapping screwed so those won't get paint (but maybe some locktite).

 

[erin]

I would say predrill holes, say 1/8" or so, then hit it with the 1/2". With a good bit and care on your part, I don't see breaking bits, it's not like your frame is hardened steel, so it should be fine. A bit of cutting oil always helps, just slow down on the exit side, it is where most people break bits, and wrists.
Definitely paint the holes afterwards.

 

[gearbox]

Sounds like good advice. I imagine the bit tends to get twisted after punching through due to the human factor. I didn't think about oil, but it's good you mentioned it.
How much pressure and speed?

I grew up in Tucson. Rather, I spent the first 18 years of my life there.

 

[Lutzy48]

Use a No.3 center drill first. It will be much stiffer than a 1/8" bit and will not be likely to break. I doubt the Locktite will do much for you with a self-tapping screw (not enough close contact area on the threads). Better off with lock washers.

 

[gearbox]

Use a No.3 center drill first. It will be much stiffer than a 1/8" bit and will not be likely to break. I doubt the Locktite will do much for you with a self-tapping screw (not enough close contact area on the threads). Better off with lock washers.

The self-tapping screws are in the cross-member which cannot be accessed to finger a nut or washer.
I figure the self-tapping screws will retain a bit of shavings and I'm not sure that would be okay with Lock-Tite. Couldn't hurt...or could it?

 

[crawler#976]

Invest a little money in a set of step bits. Start with the smaller size bit - it works as a center drill as well.

You'll get a better, truer, round hole in thin material. I use the first three sizes shown. I use mine regularly in all types of material up to 1/8" thickness. They also deburr the hole when the next step makes contact with the stock. Here's several choices - but as with any tool, you get what you pay for...

Mark

http://store.summitracing.com/egnsearch.asp?N=401145+321153+115&autoview=sku

http://www.coastaltool.com/cgi-bin/...it.htm?L+coastest+lhmh4969ff321a32+1195111338

http://www.airtech-streamlining.com/miscpages/tools.html
http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=96275

 

[BigAl]

I think the reason guys dread these kinds of projects is b/c of dull drill bits. When the bit dulls and stops cutting, you work five times as hard and make 1/2 the progress. I bought a tool called the drill doctor. It works great even though when you see it you think RONCO! If you were drilling your frame with a press you could do 8 holes with one bit no problem. With a hand drill you get a lot of wobble and the bits dull quickly. My advice is keep your bits sharp.

 

[Nullifier]

Invest a little money in a set of step bits. Start with the smaller size bit - it works as a center drill as well.

You'll get a better, truer, round hole in thin material. I use the first three sizes shown. I use mine regularly in all types of material up to 1/8" thickness. They also deburr the hole when the next step makes contact with the stock. Here's several choices - but as with any tool, you get what you pay for...

Mark

http://store.summitracing.com/egnsearch.asp?N=401145+321153+115&autoview=sku

http://www.coastaltool.com/cgi-bin/...it.htm?L+coastest+lhmh4969ff321a32+1195111338

http://www.airtech-streamlining.com/miscpages/tools.html
http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=96275

I agree step bit for sure. I have drilled into many a frame over the years and step bit are the way to go.

 

[ntsqd]

Use a real cutting oil, not ATF or some other homebrew concoction. There really is a difference and it is worth the price.

Second using sharp bits. I prefer 135* split points over the std, but the step-drill/Unibit advice is good too. If you don't get a Unibit, buy stub length drills. They are shorter so they're harder to break, they're the 135* split-point so they self-center better, and they've got a higher percentage of cobalt in them so they stay sharp longer.

A good RoT for drill step size is to drill a pilot hole that is just slightly bigger than the web of the next size drill. The web is roughly the diameter of the length of the straight edge btwn the cutting edges of the tip (or the combined length of the two secondary cutting edges of a 135* drill). If you are doing the drilling in a press, then only one pilot hole is really needed. Keep the number of pilot holes to minimum, each intermediate sized hole is another chance for the hole to drift away from where it wants to be.

I would NOT use a self tapping bolt for that. If you can't reach the backside to install a nut, then consider tapping the frame for a real bolt. Otherwise consider installing a thru sleave and putting the nut on the inside face of the frame rail.

You can do this w/o welding.
Drill the bolt clearance hole all the way thru the frame rail. Pay particular attention to keeping the hole perpendicular to the frame. Then find a piece of heavy wall tube or steel (NOT iron!!!) pipe that just fits over the bolt. Drill the inside frame hole, ONLY, to a size that allows the tube/pipe to be inserted from the backside until it hits the inside surface of the outer part of the frame. A Unibit will likely be particularly handy for this step.

Three on-line machine shop tool vendors:
MSC Direct
Enco
Travers

 

[RoundOut]

I recently did this on my Tundra, which won't be radically different than your Taco. We needed an angle drill to get the holes drilled in certain places. Also, we used 2 titanium bits, alternating bits on each hole drilled, so it didn't get too hot. They never got dull enough to notice. We sprayed WD-40 on the hole as it was being drilled. Worked great.

 

[IntrepidXJ]

as stated above, unibits (step drill bits) are the way to go

 

[spressomon]

I just drilled 12-13/32" holes in my frame (I used 10mm bolts) for the lower slider mounts (to keep the side plates flush with the bottom of the frame). I just center punched and drilled with a quality 13/32" bit. Using the step bit procedure would surely be better...especially for 1/2"...but I had no issue with how I drilled mine. And a shot of primer on the exposed edges couldn't hurt...

 

[Grim Reaper]

Use a real cutting oil, not ATF or some other homebrew concoction. There really is a difference and it is worth the price.

Second using sharp bits. I prefer 135* split points over the std, but the step-drill/Unibit advice is good too. If you don't get a Unibit, buy stub length drills. They are shorter so they're harder to break, they're the 135* split-point so they self-center better, and they've got a higher percentage of cobalt in them so they stay sharp longer.

A good RoT for drill step size is to drill a pilot hole that is just slightly bigger than the web of the next size drill. The web is roughly the diameter of the length of the straight edge btwn the cutting edges of the tip (or the combined length of the two secondary cutting edges of a 135* drill). If you are doing the drilling in a press, then only one pilot hole is really needed. Keep the number of pilot holes to minimum, each intermediate sized hole is another chance for the hole to drift away from where it wants to be.

I would NOT use a self tapping bolt for that. If you can't reach the backside to install a nut, then consider tapping the frame for a real bolt. Otherwise consider installing a thru sleave and putting the nut on the inside face of the frame rail.

You can do this w/o welding.
Drill the bolt clearance hole all the way thru the frame rail. Pay particular attention to keeping the hole perpendicular to the frame. Then find a piece of heavy wall tube or steel (NOT iron!!!) pipe that just fits over the bolt. Drill the inside frame hole, ONLY, to a size that allows the tube/pipe to be inserted from the backside until it hits the inside surface of the outer part of the frame. A Unibit will likely be particularly handy for this step.

Three on-line machine shop tool vendors:
MSC Direct
Enco
Travers

That right there is a man that knows how to poke some holes!


Most people drill WAY too fast. 600RPM is plenty. Oil, oil oil! keeps the bit bit sharper longer and keeps it cooler. Moderate pressure should be all it needs if the bit is sharp.

I like Home Depot sold drill bits. I forget the brand but the package is red. I like them because the return people don't understand what is covered on the waranty!

I keep the package and if I cant get my drill doctor to re point them I take the screwed up bit and the package to the return lane and point to the "Lifetime warranty" on the label and get a new one. :wings:

 

[david despain]

boelube

boelube is good stuff. the paste will work well in this instance i think. http://www.skygeek.com/drilling-aid...&match_type=&gclid=CImLkbD_6Y8CFQU6awodTli4DQ

i second the drill doctor. it might pay for itself on this one job. dont get bits from harbor. they are junk.

 

[madizell]

On the question of painting the holes. Painting never hurts, but you will need to clean and degrease all holes if you intend to paint. I usually paint such holes if they are to have a bolt simply pass through. If you intend to use self-tapping bolts, consider using anti-sieze on the threads. It will make tapping easier, and the stuff prevents most corrosion for quite a long time. You can also remove the bolts once fully seated, recoat with anti-sieze, and reinstall.