Notching tubing

[Jason280]

I am building a table using 2.5" schedule 40 steel tubing and a 30x72" 1/4" thick top. Planning to notch the ends where the frame will **** up to the legs, but my first go at it with a 2.5" Lenox bimetal hole saw failed miserably.

I have the tubing secured in a pipe vise, bolted to another steel table....I'm running the hole saw bit in a Milwaukee mag drill, so the set up is stable. Problem is, first go stripped the arbor. I centered the arbor back up, then welded it in place, and results were not good. Cut was erratic, and ended up eating most of the teeth off the bit. I'm hoping it was simply an older, dull bit that was the culprit....but I'm not sure.

I just picked up a new Lenox hole saw bit, any suggestions?

 

[Flail]

Do it without a hole saw:

 

[Mohawk Dave]

Too fast even with Mag Drill. IIRC my Hougens are around 600rpm. A hole saw like that on DOM or Chromoly I turn around 20-50 rpm with cutting oil.

If your holesaw arbor has the 2 locating pins, don't use them...that's for wood stuff. They allow too much play, just let the holesaw screw all the way down the threads.

Are you sure your setup is totally rigid? Uber important for hole saws.

Or do it by hand like Flail said.

 

[Flail]

I’ve used hole saws to do this but like you’re experienced, things get tore up. Drill bits in the center of the arbor will typically snap and I replace them with a grade 5 or better bolt shaft that extends all the way through both walls of the pipe in a pre-drilled hole. Also don’t use just “spin on” hole saws, use the type that have additional pins to drive the hole saw. Like this: https://www.homedepot.com/p/Milwauk...-Arbor-W-Pilot-Drill-Bit-49-56-7250/202256264.

While your nag drill setup maybe rigid, it is likely spinning to fast. It might be better to use a drill press or mill if you can dial the rpm down.

When all is said and done, I find with large tubing, like you are using, it’s just easier to wack off the opposing edges off the tube with a chop or band saw like in the YouTube example.

 

[zmotorsports]

What are you planning to use for welding it together?

If TIG then yes, get a very tight fitup with either a hole saw or use emery rolls to sneak up on the cope. If you plan on using a MIG welder the gap is a little more forgiving and you can cut a 45* angle on either side creating an upside down V (^), then put a slight radius on the point and it will fit against the other tubing in the node well enough for a solid weld. I've used either a chop saw to create the cuts or even a disc sander with 50-grit to knock the corners off if in a hurry. Both will create a tight enough joint for MIG welding.

 

[sberry]

There is a huge fascination with tube and benches and miters here. I have built over 200, never once cut anything other than 90, almost never cut 45, chop saw hasn't moved in decades and if I need to zip it with a plasma or Sawzall.

 

[ez-duzit]

Use an extra-heavy-duty arbor and turn it slowly using cutting fluid. Bi-metal hole saw should be OK, but might need to use carbide-toothed hole saw. Make certain entire setup is rigid.

 

[Bigblue&Goldie]

I'm not sure that I've ever seen tubing over 2" notched with a hole saw. I will say, I use an abundance of cutting fluid when I notch with a hole saw.

Just to verify, you are just notching the end of a piece of tube and not trying to plug a whole hole through the tube?

If you are having issues with standard arbors, check out Paragon Machine Works for some beefier arbors. They make bicycle frame building tools, but I find a lot of their stuff is great for general fab work. I forget how much they cost, but they are pretty darn reasonable.

 

[ez-duzit]

...check out Paragon Machine Works for some beefier arbors...I forget how much they cost, but they are pretty darn reasonable.

WAY reasonable!

 

[Jason280]

I may have been turning the bit too fast, my mag drill will slow down enough to tap so I'll turn the speed waaaay down. I didn't particularly want to use tubing, but this stuff was cheap....$5 per 8' stick. Plus, I want it to be heavy as possible.

Yes, I am just notching the end of the tubing to MIG weld. it doesn't have to be a perfect notch, but it will make welding easier.

 

[MJD1]

Cutting wheel. Make a test notch, grind to fit. Once your satisfied with the fit wrap it with paper and trace. With practice you can cut them amazingly close freehand then a little grinding gives a good fit.

 

[sberry]

If it's welded out I am in the make a pattern, plasma cut camp.

 

[jubilee]

2.5” tube needs to be saddled with torch. Wrap around patterns readily available. If you don’t care what it looks like ,but want a good non filler weld, heat it and mash end flat.

 

[Doug Arthurs]

I have used a free program for this when I didnt have a mill. You entered the two pipe sizes and the angle they meet at then print and cut out the pattern. Trace it on the tube and grind to the lines.