pipe notching with a hole saw??

[brendan h]

reads around that you can notch pipe with a hole saw. i need to however not holes on angles how do the hole saws handle that? and what size hole saew do i use if my pipe is 42mm OD. would i use the closes holesaw below example 41mm or the closes above eg 43mm

the pipe is 3mm wall thickness

 

[piman]

Hello Brendan,

to do it satisfactorily it needs both the drill and the workpiece to be held securely. I think that it would be difficult using a portable drill for instance? The easiest machine to use would be a lathe with the hole saw in the chuck and the tube clamped to the cross slide, which can be rotated accurately to whatever angle you want.

For best fit then go smaller and file to size but for a quick job go larger.

Alec

 

[brendan h]

i will be using a milling machine with a vice. the machine will tilt to an angle

 

[piman]

Hello Brendan,

Should be no problem whatsoever, although an end mill would be more accurate. Possibly you could also use the hole cutters for magnetic drills?

By the way the hole saws do not need the pilot drill if the work is clamped hard, this could deflect at angles unless the pilot drill is removed.

Alec

 

[brendan h]

yes but my mill isnt rated for a 42m end mill. and it would probably be cheaper to use hole saw.

so i found out i can get a 41mm hole saw or a 43mm. i think i will go with the 43 because the pipe is 43.5 mm OD.

so 43mm hole saw, clamped tight, lots of coolant/lubrication. slow speeds

 

[piman]

Hello Brendan,

yes, should be fine, I have drilled tube with a hole saw in a pillar drill, no problem. As you say they are cheap enough.

Alec

 

[brendan h]

thanks

 

[Weldingartisan]

The problem with hole saws on milling machines is a secure mounting as most arbours have too much play in them and don't cut to size. Mag drill broaches are good and take far less power (and cost less) than an end mill. I bought a morse taper blank and machined it to suit broach bits which works well. W/A

 

[brendan h]

the notch doesnt have to be perfected. im making up a bull bar for my car

 

[Hitch]

We use rotabor bits in a mill normally.
Doesnt sound like its worth it for this job though.
Id go for the 43, its 3mm thick, so a mm or 2 gap will very easily be welded up.

Avoid the bosch powerchange holesaws/arbors though

A decent Bahco/starett will do nicely.

 

[brendan h]

ok i have a hole saw 44mm will this be close enough to do the job?

 

[piman]

Hello Brendan,

yes, I would say so, you can dress the tube once it's tacked in position to close the gap a bit but it should weld up fine for a bull ('Roo?) bar.

Alec

 

[brendan h]

by dressing you mean hitting with a hammer to close the gap a little. i went and tryed a notch to test it out and welded it.

notch cam out quiet good apart from stalling my drill a few times. the notch wasnt dead center of the pipe so it didnt trun out stright. any iders on getting the notch in dead center.
the weld came pritty good apart from all the smoke from the oil i couldnt be bother to clean off properly. i TIG welded it together and was using a 1.6 tungstem and 1.6 wire. seemed good nice flat weld