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Drilling inside diameter DOM tube

bp71k5

bp71k5

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I'm working on some seat mounts and I have some 1.5" DOM tube that I am planning to sleeve with 1.25" tube. Before I welded up the larger tube, the smaller one fit inside fine. Since being welded, the larger tube seems to have shrunk/warped slightly so I can't get the smaller tube to fit inside anymore.

I'm looking at trying to hone/drill the inside of the larger tube and I'm wondering if a 1.25" diamond coated hole saws might work as an alternative to a more expensive 1-9/32" (32mm) drill bit? Have anyone cut steel with a hole saw made for tile/stone? Waste of time/money?


-Brian
 
i'd run a hone thru it... tight ball hone to clean it up, then a stone if it needed it.. how bad is it?
 
ryoken said:
i'd run a hone thru it... tight ball hone to clean it up, then a stone if it needed it.. how bad is it?
Click to expand...

It looks like the tube is warped a bit and looks just out of round. I can't get the smaller tube to even start to slide in. I'm thinking a hone might not be enough, hence looking at more aggressive options.


-Brian
 
bp71k5 said:
It looks like the tube is warped a bit and looks just out of round. I can't get the smaller tube to even start to slide in. I'm thinking a hone might not be enough, hence looking at more aggressive options.

-Brian
Click to expand...

I'd be willing to try a hone though. Got any online links to look at?


-Brian
 
Not sure what you're trying to accomplish or how the fit needs to be. Another option may be heating the outer tube very hot and pressing them together.

Probably a one shot deal.
 
cybrfire said:
Not sure what you're trying to accomplish or how the fit needs to be. Another option may be heating the outer tube very hot and pressing them together.

Probably a one shot deal.
Click to expand...

I'm using the smaller tube as a removable "pin" that will let me remove the back seat quickly so the pin needs to be removable. I did manage to get it in a little bit but it stuck and I had a heck of a time getting it back out. Just picked up a larger bit and a brake hone to give those a try. Will post pics if I can get it to work.




-Brian
 
die grinder with a sanding drum may get it done for you then.
 
I'm thinking a curved file / rasp would be easier to stick down a 4" length than, say, a sanding drum... :thinking:

-- A
 
I would suggest you somehow make the OD of the 1.25" tube slightly smaller (lathe is best).
 
I'm with 4x4 high, instead of trying to remove some material from the id of the larger tube, it would be quicker and a lot easier to chuck up the inside tube and take .0025" off at a time and see how much you need. If you don't have a lathe available then you can use a grinder on the od of the inside tube and slowly roll it and grind it at the same time. Probably be best to use a sanding disk not a grinding disk that way a smaller amount of material is removed each time
 
I managed to find a metal hole saw that did ok along with a brake hone. It's still tighter than I'd like but it's ok for now.

Here's the bracket assembled for testing. The smaller center pin is removable and allows the larger section of tube to come out.
seat brackets 005.jpg

1.25" Pin removed.
seat brackets 007.jpg

That section removed will have a couple bars going to the other side of the bed to make a frame for my seat to mount on. Then I can remove the seat simply by pulling out the two long pins. Not sure about seatbelts yet.
seat brackets 008.jpg

You can see why I was trying to remove material from the inside of the 4" sections of large tube rather than trying to remove material from the entire length of the pin. After some testing with different tools, a sanding drum on a die grinder seems like it works ok. I just need to find a courser grit that's closer to 1.25". The ones I have are only 1" and aren't agressive enough. The brake hone also works ok, but it just smoothes out the bore after it's cut with the hole saw and doesn't remove much material itself.

Spent two solid days so far on a project that was supposed to take a couple hours...

seat brackets 005.jpg

seat brackets 007.jpg

seat brackets 008.jpg
 
Last edited:
bp71k5 said:
Spent two solid days so far on a project that was supposed to take a couple hours...
Click to expand...

Project, noun: An activity to occupy time, generally at least twice the allotted time, even when taking this fact into account. :haha:

At work we say "The first half of the project takes the first 90% of the time.

The other half of the project takes the other 90% of the time."

-- A
 
Brian,

Same thing happened to me on my tire swing gate.

Its a lot easier to turn down the sleeve than it is to bore out the receiving tube.... I ran the sleeve on my 20" disc grinder (just kind of lightly rolled it around to bring down the O.D.) you could accomplish the same thing with a flap wheel disc and grinder if you are careful and do a lot of test fitting.

:usaflag:
 
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