[4]

Arbors and Hole Saws for Tube Notching?

erikmannie

Active Member
Registered
Joined
Sep 8, 2019
Messages
94
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

Active Member
Registered
Joined
Sep 8, 2019
Messages
94
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.

IMG_6798.JPGIMG_6799.JPG
 

erikmannie

Active Member
Registered
Joined
Sep 8, 2019
Messages
94
Here is the hole saw which uses a 3/8" arbor. I am not sure if 3/8" is rigid enough.
IMG_6800.JPG
 

benmychree

John York
H-M Supporter - Gold Member ($25)
Joined
Jun 7, 2013
Messages
3,749
I have seen an R-8 arbor that screws directly into the hole saw; it may have been home made.
 

eugene13

H-M Supporter - Gold Member
H-M Supporter - Gold Member ($25)
Joined
Nov 19, 2014
Messages
469
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

Active Member
Registered
Joined
Aug 3, 2017
Messages
205
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

Newbie
Registered
Joined
Sep 16, 2019
Messages
2
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

Active Member
Registered
Joined
Sep 8, 2019
Messages
94
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.

IMG_6801.JPGIMG_6802.JPG
 

erikmannie

Active Member
Registered
Joined
Sep 8, 2019
Messages
94
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.

hougen.PNG
 
Last edited:

erikmannie

Active Member
Registered
Joined
Sep 8, 2019
Messages
94
And a Lenox that I will try. Looks like a standard 3/8" shank.

lenox.PNG
 
Last edited:

RJSakowski

H-M Supporter - Gold Member
H-M Supporter - Gold Member ($25)
Joined
Feb 1, 2015
Messages
4,410
If you want to cut holes at other than 90º, you will need to make a jug/fixture to do so. Angle iron would form a suitable cradle and a hginge and an adjustable brace would allow setting the desired angle. It should be well secured to minimize shifting and vibration. Cutting a hole at that angle will require a very rigid hole saw setup due to the extreme side forces at play.
 

mikey

Active User
H-M Platinum Supporter ($50)
Joined
Dec 20, 2012
Messages
5,840
You might consider a fine pitch roughing end mill and a swivel base for your vise if you plan to use the mill. An even faster way is a custom small wheel attachment on a belt sander - it will notch tubing in seconds.
 

erikmannie

Active Member
Registered
Joined
Sep 8, 2019
Messages
94
If you want to cut holes at other than 90º, you will need to make a jug/fixture to do so. Angle iron would form a suitable cradle and a hginge and an adjustable brace would allow setting the desired angle. It should be well secured to minimize shifting and vibration. Cutting a hole at that angle will require a very rigid hole saw setup due to the extreme side forces at play.
This required rigidity is probably why the school used a Bridgeport knee type mill.

I will be making so many of these that it would be worth my time to make a fixture. That would be great if I didn't need to tilt the mill head so often.
 

erikmannie

Active Member
Registered
Joined
Sep 8, 2019
Messages
94
You might consider a fine pitch roughing end mill and a swivel base for your vise if you plan to use the mill. An even faster way is a custom small wheel attachment on a belt sander - it will notch tubing in seconds.
My vise does have a swivel base, but I am not seeing how to use the swivel base to cut a 60 degree notch.

The benefit of a mill for mitering tubing for bicycle frames is that you end up with such a great fit up. The goal is a 0.1mm gap.
 

erikmannie

Active Member
Registered
Joined
Sep 8, 2019
Messages
94
Here is a 1 1/4" roughing end mill. I would have to see if I have an R8 collet large enough for that.

snip3.PNG
 

erikmannie

Active Member
Registered
Joined
Sep 8, 2019
Messages
94
This muffler tubing is CREW (Cold Rolled Electronically Welded). I will also be mitering 4130 chromoly between .020" and .050", Grade 2 Ti no thicker than .040", and aluminum (alloy and wall thickness TBD).

Definitely need to have the feeds and speeds dialed with as much rigidity as possible.
 

mikey

Active User
H-M Platinum Supporter ($50)
Joined
Dec 20, 2012
Messages
5,840
If you plan to do a lot of cuts at odd angles then a 3-way tilting vise might be worth buying. They are expensive but will hold the work very securely for use with a milling cutter. Wilton makes one and I'm sure there is a cheaper import out there, too.

At these prices, I would seriously consider a 2 X 72 belt sander with small wheel attachment. It would be an extremely useful tool for a fabricator to own. This will give you and idea of what I mean.
 

erikmannie

Active Member
Registered
Joined
Sep 8, 2019
Messages
94
If you plan to do a lot of cuts at odd angles then a 3-way tilting vise might be worth buying. They are expensive but will hold the work very securely for use with a milling cutter. Wilton makes one and I'm sure there is a cheaper import out there, too.

At these prices, I would seriously consider a 2 X 72 belt sander with small wheel attachment. It would be an extremely useful tool for a fabricator to own. This will give you and idea of what I mean.
Wow, that tube notching belt sander in the video was making quick work of that tubing!

I had not even realized that they made tilting vises. After buying the mill and lathe and paying for school, I will be out of money for the next year; also, my garage is stuffed.

What is the argument against tilting the mill head? Maybe a PM-25MV isn't rigid enough? I am about to find out.

vise.PNG
 

ErichKeane

Active Member
Registered
Joined
Aug 3, 2017
Messages
205

benmychree

John York
H-M Supporter - Gold Member ($25)
Joined
Jun 7, 2013
Messages
3,749
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
That cutter would not work on tube as required, it is too shallow.
 

erikmannie

Active Member
Registered
Joined
Sep 8, 2019
Messages
94
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.
 

erikmannie

Active Member
Registered
Joined
Sep 8, 2019
Messages
94
That cutter would not work on tube as required, it is too shallow.
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.
 

C-Bag

Ned Ludd's bro
H-M Supporter - Gold Member ($25)
Joined
Feb 9, 2017
Messages
1,071
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.
 

mikey

Active User
H-M Platinum Supporter ($50)
Joined
Dec 20, 2012
Messages
5,840
What is the argument against tilting the mill head? Maybe a PM-25MV isn't rigid enough? I am about to find out.
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.
 

whitmore

Active Member
Registered
Joined
Mar 3, 2017
Messages
427
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).
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.
 

pontiac428

Mo-Max
H-M Supporter - Gold Member ($25)
Joined
Apr 23, 2018
Messages
827
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.
 

ErichKeane

Active Member
Registered
Joined
Aug 3, 2017
Messages
205
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.
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.
 
[5] [7]
Top