Arbors and Hole Saws for Tube Notching?

erikmannie said:
Here is a Hougen that looks like it fits the bill. The picture shows the hole saw on its arbor. I would be surprised if the arbor is included for $14.85.

The arbor has three flat sides, so it would almost certainly fit in a drill chuck.

View attachment 303179
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That cutter would not work on tube as required, it is too shallow.
 
At one of my jobs, I used annular cutters in a mag drill for holes in up to 2” plate. The pits are very sharp, and they do a great job.
 
benmychree said:
That cutter would not work on tube as required, it is too shallow.
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The cutter should be every bit of 1 3/4” long.

Due to budgetary limitations, my first plan will be to tilt the head of the mill and use a long HSS hole saw with a 3/8” shank.
 
My experience with tube notching was making a frame for my powdercoat enclosure out of 3/4" EMT. I used a HF notcher that of course needed quite a bit of beefing up and modding. I also used my benchtop drill press and what the whole process taught me was verticle is not the proper direction even with a tilting head. Something like the Ol' Joint Jigger or others like it is the ticket IMHO. I saw quite a few in race car shops. If I was thinking machine tool I'd go with a horizontal mill because then it would be easier to make an adjustable tubing vise. Or best of all build a really heavy duty joint Jigger style.
 
erikmannie said:
What is the argument against tilting the mill head? Maybe a PM-25MV isn't rigid enough? I am about to find out.
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Other than the tedium of having to realign it afterwards, nothing. A tilting vise just makes things simpler and the index marks make it easy to reproduce angles. It isn't necessary and you can make jigs instead.

There is no doubt in my mind that if tubing work was a key focus for me, I would use a belt sander.
 
erikmannie said:
One of the main reasons that I bought my benchtop mill is to notch tubing.
All of the hole saws that I see online are for use with a hand drill (3/8” shank).
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You can get 1.25" endmills (roughing would be OK), even indexable carbide ones. And an R8 shank 1.25" holder
shows up on eBay for not much money. It's likely that a three-jaw chuck and floppy arbor (like for a hand drill
operation) won't be as effective as just... a big hunk of cutter.

The tubes will come out better-looking if you put some aluminum soft jaws on the vise, and cut them into
C-blocks, then just mill your cuts through them (holding the tube with lower pressure over
a large area). rather than extending out from the vise.
 
I use hole saws for racecar/rock crawler stuff. They do the job. But if you're talking about notching a set of Tange Prestige triple-butted CrMo, you're gonna want better than 1/8" of precision. For that, you'll want to buy annular cutters for the sizes of tubing that you will be joining. You want those TIG welds to look even and straight? (practice practice) you'll need to hand fit that joint together within a hair's width. You can hide welds from your customers with bondo, but it would be better if you had perfect fishmouths to start with. That's why annular cutters.
 
whitmore said:
You can get 1.25" endmills (roughing would be OK), even indexable carbide ones. And an R8 shank 1.25" holder
shows up on eBay for not much money. It's likely that a three-jaw chuck and floppy arbor (like for a hand drill
operation) won't be as effective as just... a big hunk of cutter.

The tubes will come out better-looking if you put some aluminum soft jaws on the vise, and cut them into
C-blocks, then just mill your cuts through them (holding the tube with lower pressure over
a large area). rather than extending out from the vise.
Click to expand...
Fwiw: I made the mistake of buying one of those R8 1" endmills holders in eBay when I first started. 3/4" into my cut, it shattered and threw my endmills on the floor. I've still got a bunch of unused 1" endmills I'll probably never use unless I need them in my lathe.
 
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