Arbors and Hole Saws for Tube Notching?

[erikmannie]

One of the main reasons that I bought my benchtop mill is to notch tubing. The first tubing that I have to notch is 1 1/4” inch diameter with .050” wall. You may know it as muffler tubing.

I am new to milling, and I imagine that I will buy an 1 1/4” holesaw. I have R8 collets for my PM-25MV milling machine. I haven’t bought a chuck yet because PM was out of stock for the chuck I wanted.

When I was in school, the instructor used a hole saw that he attached to an arbor. At school, they used a Bridgeport. It was a bicycle frame building school, and the students were not allowed to touch the mill.

All of the hole saws that I see online are for use with a hand drill (3/8” shank). Many hole saws online are bi-metal HSS.

Does anybody know of a product that could notch thin wall tubing with a mill? What kind of arbor will I use? I want it to be thicker than 3/8”.

 

[erikmannie]

It looks like I will have to tilt the head 60 degrees because the clamp in the V-block would interfere with the cutting tool if I put the workpiece at a 60 degree angle in the vise. At the school, they were constantly tilting the head back and forth to different angles.

It is painful to see that rusty tubing clamped onto the new V-blocks. When I make the cuts, I will clean the tubing.

 

[erikmannie]

Here is the hole saw which uses a 3/8" arbor. I am not sure if 3/8" is rigid enough.

 

[benmychree]

I have seen an R-8 arbor that screws directly into the hole saw; it may have been home made.

 

[eugene13]

I use hole saws in my mill doing the same thing. Lennox saws seem to hold up better than the other brands and offer the best concentricity. If you're looking for a dedicated tubing notching fixture check out the Old Joint Jigger. You can build your own mandrel out of round stock by drilling and tapping a 5/8 18 or 1/2 20 hole in one end and using a short grade 8 stud. I have some pictures of the ones I built, I will post when I find them.

 

[ErichKeane]

I've generally had terrible experiences with hole saws. I might suggest going with an annular cutter. They are significantly more expensive, but are much less likely to walk out on you, and will cut significantly more 'round' than a hole saw.

As far as tiling the head, you seem to have a rotary base on your mill vise. Could you just use that to set the 60 degrees?

 

[RapidTransit440]

I'm using Blair/Hougen Holcutters, the result with these things are amazing. AFAIK there is no visible wobble from runout that isn't related to my current "quality" chuck. No visible wobble on my hand drill (Has an upgraded aftermarket Jacobs chuck)

I've been eyeballing the Keyless Llambrich JK chucks Just an idea to look at, although depending on your machine and how much you want to spend you may want to look at Albrecht

 

[erikmannie]

Here is a picture of the Ol' Joint Jigger in use. Thanks for that tip.

 

[erikmannie]

I can't figure a way to get my rotating bench vise to get the 60 degree angle unless the head of the mill is tilted 90 degrees (as in photo above of the Ol' Joint Jigger).

I just bought a PM keyless chuck with an R8 shank. It accepts 1/8"-5/8" shanks.

I will check out Lennox and Blair/Hougen Holcutters along with annular cutters.

I will be making these which are used for practicing TIG welding on acute and obtuse angles in bicycle-sized tubing. At bike school (UBI), they called these "gruelons" because the students find the acute angles grueling to weld.

 

[erikmannie]

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.