Replacing a A-frame Jack, need to enlarge 2" hole to 2-1/4"

You can only use a hole saw if there is a center. The hole saw has a small drill bit in the center, maybe 1/4 in or so in size. That 1/4 bit is the guide that keeps the big circle saw blades in place. Without that center bit, or without a center to the hole, there is no way to use a hole saw, it will just scramble all over your work space.

You can weld a plate, then drill through the plate and the part you want to enlarge (but lets face it, a guy who can weld is not asking an RV forum how to drill a hole in metal), or
maybe attach a piece of wood there to act as a center point for the saw, wood will be easier to drill through than another layer of metal too.

The easiest is to just grind away. This sounds like a lot of work, but really should be the easiest. I personally do not have a grinder that small that would fit inside a 2 inch hole. The link given for HD's grinder will not work either - too big.
I have used a file to make this kind of hole bigger, but 1/8 inch all the way around (makes it 1/4 bigger) will be a lot of hand work on steel.

Cutting slots and bending will make a mess. This would work on thin metal, but trailer frame metal is too thick.

Consider that a jack is not a precision instrument. Maybe you dont need to make a perfectly symmetrical circle in the center-line of the trailer. Make your cut/grinding off-set, to the front, to the rear or even to the side, so just grind away half and when the new jack fits then slide it in. Hand grinding will not result in perfection. Make a circle mark with a sharpie before you begin so you have reference as when you grind you lose the original circle that was your starting guide.

okhmbldr wrote:
Use a grinder bit in your drill....just keep going round and round until the hole is the size you need.

And Kiss that drill motor good-bye.
Then spindle bearings will be gone.
(An acquaitence - no longer a friend - did that to one of mine.)

Do you have a friend that has an engine lathe?
Ask him to make a 2" plug with a 1/4 hole and them put a plain 1/4 in the center drill of a hole saw.

Matt

Trailmanor13 wrote:
I was thinking of using my sawzall with a diablo metal blade and cutting 8 cuts about 1/4 of a inch in and using a vicegrip to bend them out some and then tapping the jack into the hole. The top hole in the A frame is big enough, just the bottom hole is too small. The metal is less than 1/8"

Spot on.

or use an angle grinder like this for less than $40:

https://www.homedepot.com/p/Stark-8-2-Amp-Corded-Electric-4-1-2-in-Angle-Grinder-with-11000-RPM-Sliding-Lock-On-Switch-45501-H/311884247

agesilaus wrote:

K Charles wrote:
2 1/4 hole saw is about $15 at any hardware store

The original hole will still have to be enlarged since the new jack will pass thru that. And I find enlarging an existing hole, with a hole saw, to be a tough job tho I'm sure there are tricks I don't know.

A good 2 1/4 in bimetallic saw blade runs about $18 plus a mandrel at $15 if you don't have one. A grinding stone is probably less than $5

which is why I recommended welding a metal plate over the existing hole to give you a way to easily use that hole saw. no ignorant sarcasm required. I have a hole saw fitting that holds a saw the size of the existing hole inside a saw that is the larger desired size. think it was called a "oops" or something like that.
bumpy

WhatCummins12V98 said. Piece of pie! The circle
you drill out of your guide piece is called a rountuit. Now you have a rountuit for all those things you have been putting off till you get a rountuit!

Drill a 2-1/4" hole in plywood or steel and clamp over existing hole centering the template over existing hole. Drill away, ez-p-ze.

I was thinking of using my sawzall with a diablo metal blade and cutting 8 cuts about 1/4 of a inch in and using a vicegrip to bend them out some and then tapping the jack into the hole. The top hole in the A frame is big enough, just the bottom hole is too small. The metal is less than 1/8"

K Charles wrote:
2 1/4 hole saw is about $15 at any hardware store

The original hole will still have to be enlarged since the new jack will pass thru that. And I find enlarging an existing hole, with a hole saw, to be a tough job tho I'm sure there are tricks I don't know.

A good 2 1/4 in bimetallic saw blade runs about $18 plus a mandrel at $15 if you don't have one. A grinding stone is probably less than $5

Use a grinder bit in your drill....just keep going round and round until the hole is the size you need.

2 1/4 hole saw is about $15 at any hardware store