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

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

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

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

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.

An angle grinder with a carbide bit like Carbide burr bit.
I've used these numerous times for enlarging holes. A grinding stone on a drill will wear down quick and take a lot longer.

I would be inclined to send it back and order a BAL 29025B, same specs as the Curt but has a 1-7/8" OD jack tube. Problem solved.

I believe you bought the wrong jack. They come in two different sizes depending upon the weight capabilities. Before cutting or grinding, I would check to see if the proper size jack assembly is available.

No need to weld a plate on to use to center the hole saw. Do like Cummins12V98 says. Clamps will work, but you can also add bolt holes to so it can be bolted down using the bolt holes for the existing Jack.

I did something similar when replacing both crummy uncovered gravity and city water fill connections on my trailer with ones that had lockable doors. I needed larger holes to install them. I cut a small square piece of half inch plywood to use as a template. I used a 4 inch hole saw to cut a hole in the template. I then mounted one of the hatches to the template using the screws needed to mount it to the side of the trailer. I then removed the hatch and screwed the template to the side of the trailer over the existing hole. It stabilized the hole saw while I cut the first hole through the side of the trailer. I then removed the template and lined it up over the next hole keeping it in line with the first hole, screwed it to the trailer and cut the second larger hole. Worked great.

Cummins12V98 wrote:
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.

mobeewan wrote:
No need to weld a plate on to use to center the hole saw. Do like Cummins12V98 says. Clamps will work, but you can also add bolt holes to so it can be bolted down using the bolt holes for the existing Jack.

yep, much easier to bolt it using existing hole pattern than clamping/welding etc. and when you get done with the hole saw your jack won't look like a cobbled up mess like some other suggestions would.
bumpy

ajriding wrote:
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.

No pilot hole needed with my method.