Functional offroad exhaust mods

[monele]

X2 on the above suggestions, Esp. the step drill (though they aren't good above about 3/16") and if you can't find cutting oil, any thick goopy oil (SAE30, Hydrualic oil etc) will make a huge difference. The point is for the oil to carry away heat and keep from smoking the bit. When the oil smokes, stop and dip the bit again. if you are going to use non-cutting spec oil, wear a mask so you don't inhale the smoke!!

Also, you need a center punch! Always mark you holes 1st (sharpie, awl what ever) and then Punch a center mark to start your drill in (if you're short on space to swing a hammer get a spring loaded punch) one good hit is better than 2-3 little ones. Start the drill slow, and check to see it's cutting where you want it to, then ramp up to cutting speed.

 

[winkosmosis]

I always use a spring loaded punch. The problem is the hole on the inside of the frame. You have to go through from the outside and drill through. To punch the opposite side you'd need a very long strong piece of metal like a nail, and then hold it straight to hit with a hammer.


I wonder how well silicone oil would work for cutting. I have some bottles of RC car shock oil in various weights. It's non toxic but I don't know if it makes toxic fumes when heated. Any chemists here?

 

[proto]

Here's an additional tip: when you're drilling vertically, say upwards into a vehicle frame, the cutting oil doesn't do much good (it just drips down away from the tip of the bit). There are a couple stick-lubricant products that are just perfect for this situation. Accu-Lube, Cut-Ease, and LSP Edge (43200, I think?) are some names.

These all come in a tube and have a kind of waxy consistency. You can dip your drill bit in them, or apply them directly to the target spot. The lube will stay in place and melt a little as you drill, providing the lubricating action. It makes a big difference.

This stuff also works on saw blades. It's nice to have around when you've got a long, tough cut through thick metal (or even wood) with a recip saw or even a hand-held hacksaw. It's also been suggested that it can be used on zippers to keep them free and working smoothly (I haven't tried that).

The best part is the convenience. You can keep a small tube in your pocket while you're working, throw it in the toolbox when you're done. It'll be there next time when you need it. No mess!

I bought a large tube about the size of a caulking cylinder at Home Depot some years ago -- haven't used it up yet. I don't know if they still carry it, but you can find it at Ace Hardware, Amazon, and elsewhere online. While you're there, pick up some of loctite's new stick threadlocker compound, too.

 

[winkosmosis]

Sticks of cutting lube? Even better. I have an anti-seize crayon and it's a lot more convenient than liquid.

 

[ntsqd]

Some stick lube options:

http://www1.mscdirect.com/CGI/NNSRIT?PMPXNO=1658822&PMT4NO=70255428

http://www1.mscdirect.com/CGI/NNSRIT?PMPXNO=1658846&PMT4NO=70255428

http://www1.mscdirect.com/CGI/NNSRIT?PMPXNO=1658821&PMT4NO=70255428

http://www1.mscdirect.com/CGI/NNSRIT?PMPXNO=1744993&PMT4NO=70255428

http://www1.mscdirect.com/CGI/NNSRIT?PMPXNO=1744994&PMT4NO=70255428

http://www1.mscdirect.com/CGI/NNSRIT?PMPXNO=5887025&PMT4NO=70255428

 

[winkosmosis]

I got a new 7 amp Skil drill http://www.lowes.com/lowes/lkn?action=productDetail&productId=300239-353-6335-01&lpage=none

But I didn't realize it was max 950rpm until I saw it on the website... nothing on the box says that. Is that too slow? Will it bog down to a suboptimal speed?

Also, I got a 3/8 bit like this http://www.lowes.com/lowes/lkn?action=productDetail&productId=122169-353-HCBG16&lpage=none
Would that work on steel? The package says "for hard materials (granite, stone, tile etc)"

 

[saburai]

Sorry! Wrong bit

That's a masonry bit. Not what's needed.

The guy's were suggesting a step bit - for metal.

 

[saburai]

More info...

Drill info:

http://en.wikipedia.org/wiki/Drill_bit

Link to a step bit set:

http://www.homedepot.com/webapp/wcs...D25X-_-100081946&locStoreNum=1265&marketID=20

 

[winkosmosis]

Drill info:

http://en.wikipedia.org/wiki/Drill_bit

Link to a step bit set:

http://www.homedepot.com/webapp/wcs...D25X-_-100081946&locStoreNum=1265&marketID=20

Is that the only kind of step bit? The wikipedia page doesn't show any.

Those ones at Home Depot won't fit. I need 6" long, and it has to go through both sides of the framerail. Is there any reason not to try the masonry bit?

 

[ntsqd]

Is that the only kind of step bit? The wikipedia page doesn't show any.

Those ones at Home Depot won't fit. I need 6" long, and it has to go through both sides of the framerail. Is there any reason not to try the masonry bit?

They will drill metal, but they are disappointing. About the time that you think it's going to work the solder holding the carbide insert in place melts and the drill bit is done.

The way to get the through hole is to use a std twist drill long enough to reach all the way through the frame rail. Once you have that pilot hole you can use the step-drill (aka "Unibit") to open up the diameter to what ever size that you need.

On speed, when in doubt go slower. Natural inclination is to go faster and that nearly always over-heats & ruins the bit.
The real formula for machining steel is: 400/drill diameter = cutting speed. So a 1/2 drill bit will want to go 800 RPM. Usually you have to take what you can get.

 

[winkosmosis]

This is the closest I can find to what I need, but it's basically the same as using a smaller pilot bit, which I'm doing

http://www.toolking.com/products/54300007.aspx?shareasale=KJD

 

[monele]

The above bit is for making pocket holes in wood, it would never last in metal. The step drill should look like a x-mas tree. I don't work on XJ's usually, so I am unsure of clearances. If you use a small, say 1/4" pilot bit from the outside so that you punch through, can you then start the larger bit from the easy to reach side of the "frame rail" to open it up? That's the only way a standard Step drill will be of any help. Oh, and X2 on the tapmatic dry lubricant. I have a stick for my metal saws and completely forgot about it. Excellent stuff.

 

[Backwoods Rambler]

Go here: http://www2.northerntool.com/power-tools/drill-bits/item-335327.htm

 

[winkosmosis]

Thanks for the link. But everything Northern Tools has is too big. The skid plate attaches with 3/8" bolts that go all the way through the frame, which is fully boxed with the unibody. That's why it's so difficult. Both the inner and outer hole must be 3/8".

 

[winkosmosis]

Some stick lube options:

http://www1.mscdirect.com/CGI/NNSRIT?PMPXNO=1658822&PMT4NO=70255428

http://www1.mscdirect.com/CGI/NNSRIT?PMPXNO=1658846&PMT4NO=70255428

http://www1.mscdirect.com/CGI/NNSRIT?PMPXNO=1658821&PMT4NO=70255428

http://www1.mscdirect.com/CGI/NNSRIT?PMPXNO=1744993&PMT4NO=70255428

http://www1.mscdirect.com/CGI/NNSRIT?PMPXNO=1744994&PMT4NO=70255428

http://www1.mscdirect.com/CGI/NNSRIT?PMPXNO=5887025&PMT4NO=70255428

I ordered the one that looks like a crayon, and the one that looks like a blue piece of soap.