Technical What tool to elongate holes in trans crossmember?

Hi guys,

I have to elongate the transmission cross member because I moved it back 1/2” with an adapter plate. I have found many references to elongating those holes but presumably the discussion is amongst people more knowledgeable than I am who just say “elongate the holes.”

I’m doing this on the side of the road without air tools, and I’m wondering what to use before I mess it up. File? Drill? Is there something I can put in my dremel? What would you do to elongate the hole 1/2” rear wards?

Sorry for the newbie question. I learn as I go.

 

Carbide burr. You just need something fast enough to spin it.

 

I have a Dremel 100 which says it a 35000 RPM. Hopefully I can find a carbide burr tip for it. I’ll try that first.

 

Just noticed your from the big smoke. Try KMS tools they’ll have lots of burrs, single or in a kit.

 

1/4" shank burr in a battery drill will take off material quickly. Just watch those little bits of swarf, they're small and sharp!

 

It sounds like a simple task. Use whatever you have handy first and only buy new bits if you have to.
I don't know if you wish to widen each hole on each side by a 1/2" or something a bit less, but a combination of drilling and hand filing might be the answer. I happen to have a rattail file with the tang broken off that I have chucked up in a battery power drill to hog out a hole or two quite a few times. If you can remove the piece and work on a tailgate or a sturdy box, that's half the battle. I don't see why you can't whistle while you work.

 

Suggest both goggles (not just safety glasses) and a full face shield. And a bunch of magnets as close as you can get them to the work area and still be able to work. I have a love / hate thing with my die grinder, but wouldn't want to be working overhead with it. In fact I'd do almost anything to avoid that, or at least minimise the die grinding. Drilling is good (with good eye protection).

Chris

 

Side of the road you say!

 

I'm with Shift Wizard. A 1/2" is too much to grind or file. Just drill a new hole with a 3/8 or 1/2 bit, then open up the remaining 'tooth' between the holes with a coarse file or a hacksaw blade mounted in one of those handles that has the blade protruding on one end.

 

I could elongate a 1/2” slot in 1/8” mild steel with a coarse burr in less than a minute.
Have a pair of tweezers handy for removing slivers, you’ll need them.

 

I got these a while back on Amazon. I know you are on the road but someone might carry them. They eat metal!

 

Please use clean or new eye protection, goggles over safety glasses, then a full face mask. Use all three items when grinding underneath a vehicle! Also, cover your (hair) head, or else when you go to remove the eye protection, metal shavings will fall from your hair into the eyes.

 

I hate grinding or using a die grinder overhead under a car .

When I have to I will get a T-shirt and wear it over my head with my eyes poking out of the coller so my entire head and neck are covered .

then goggles or a full face sheild .

don’t remove anything untill your out from under the car and bend over and stair at the ground that way the chance of getting stuff in your eyes is a minimum.

also it helps a bit but smearing grease into and around where you are hogging out material helps a bit in some of it will get stuck to the grease instead of falling on you .

eitherway it’s*****ty work .

good luck

 

Thanks everyone for all the knowledge. You may notice my account is 13 years old but this is my first post - I use the “search” religiously and read voraciously on here. This site is my #1 resource keeping my cars running. I’ll leave this thread up to contribute to the search database!

I went with a 1/8” carbide burr for my Dremel, and it worked well enough, took maybe 15-20 minutes to elongate both holes to my satisfaction. I slipped a paint stir stick between crossmember and mount to avoid damage to the threaded holes with grinding. Obtained some slivers. Luckily this is a small step van so there’s room to work (14” anyway) under the truck/transmission, and my other step van is an ice cream truck so I drove it down there for electricity . Oh, and also I had a typo in my OP, I needed to elongate about 1/4” not 1/2”. Would have used a file but didn’t have a round one anyway and the rain is coming in, plus with the crossmember and transmission still both mounted I wouldn’t have had much vertical travel distance for the file.


This part of the job is done. I’ve been installing a Danchuk 10-100 plate between a 292 and TH350 to hold an old-style trans-mount GM starter because the previous owner sheared off the entire side of the outer starter hole. It was my first time separating a transmission from an engine, and also first time removing drive shaft. I don’t have anywhere to work at home so I’m down on a flat quiet road 10 minutes from my house. A milk crate was perfect as a transmission “jack” (holder/stand without up/down), it’s the exact size of the TH350 pan. Everything is back together except somehow I lost trigger power during the melee.

RmK57, I am also in North Van, near Cap Mall.

 

Are those things decent quality? That is incredibly cheap for carbide bits.

 

Whatever you do wear eye protection and a face shield.

 

That's the ticket, and I would use a step bit, to get a perfectly round hole. I did one today, but it was removable, so the Bridgeport made it easy.

 

“….I’m down on a flat road about 10 minutes from my house.”
Well that deserves an attaboy, your tenacity is impressive!

 

Whoa you are one tenacious guy. Way to go.

 

I use the good old fashioned Swiss Hand Mill, aka a rat tail file. Slow and steady. Gives the hands and arms a good workout while enlarging the hole. I find that carbide burrs always catch and chatter usually boogering up the hole. I suppose if you have an old corded electric drill that spins faster than the typical cordless, that might work. You'll still get hot slivers down your shirt though.

 

Draw some lines, mark the rear of the hole, drill a new hole at the rear area the same size as the front hole (in steps with lube), drill more holes in between (inside the area you marked out) and connect the dots. The more material you drill out the less material you have to file/grind.

Had to do it many times in the past BT (before tools). Something kinda like this:

 

I can tell you I have used 3 of them out of the set (and I am not particularly kind to tools) and they worked amazingly well. Thats a good 20 bucks.

 

Carbide……oh what fun it is when they grab…..

 

Color me spoiled... I had to do one on a junkyard '66 Chevy crossmember I was using. Into the Bridgeport vise, done in 10 minutes, no slivers. You an never go wrong with drilling a hole and filing out the web between them if you have to go the caveman route.

 

While I admire your fortitude in "doing whatever it takes" to get the job done, if you like old cars you really really need to build yourself a shop or move somewhere that has a shop......... I used to have a 33 Ford that I worked on in my driveway and it took too much time getting tools out and putting them away, so I sold the car.
Then I built me a garage and I could leave my tools just lying there till the next day or whenever...........

 

Great idea, but he lives in the most expensive city in Canada to live in. It's very expensive to own anything there, nevermind room for a shop or decent sized garage.

Sounds like he's being resourceful given his personal circumstances. I wouldn't give up my well-equipped garage for anything, but we don't all have the same fortune in what we can afford sadly.

A single family home with a carport I think usually starts around $1.5M in North Vancouver.

 

If the crossmember in question is accessible and easy to remove, I would look into jacking up the trans, pulling the xmember, and using the carbide but on the tailgate or on a stump, where the grinding swarf doesn’t fall on your head.
A few minutes prep time is often well worth it, as a distasteful job becomes more pleasant.

Congratulations on your success, though.

 

Might have to wait till April when it stops raining.

 

Thanks Billy - I've now ordered a set of the burrs.

Dremel stuff is hit-and-miss. The Dremel branded gear is pricey, and often no better lasting than the knock-off stuff. Some of the knock-off stuff is pretty bad though. Good to hear a recommendation for stuff that works - appreciated.

Cheers,
Harv

 

I use a harbor freight die grinder.