tubing notchers, angle protractor

[weezilco]

Dear framebuilders,

While puttering with my flyweight motorbike frame the other day, I was thinking how nice it would be to have a proper tubing notcher to fit to my drill press. Fishmouthing by hand with a round back file is pretty tedious and it's going to be much more so when I start on the frame for the 50cc lake bike, where I'll need to make dozens of tubing joints.

I was interested to note that the hole saws either provided or recommended for use with the notchers I've found have very coarse teeth (~12-14 teeth per inch) as though for use with wood.



Quietly, this doesn't seem right to me, but the salespeople insist that those are the right sorts of hole saws to use. Are there not any hole saws out there with something like 18 t.p.i., more resembling those on a bandsaw or hacksaw or will the recommended ones work OK?

I found a rather inexpensive notcher at Hare & Forbes ($140). Chinese made. Anyone have any experience with this or similar low-buck tools?

I'm also looking for a protractor with arms like this one:



Haven't had much luck finding one in Australia. Looks mighty handy.

Thanks again,

-Brian

[gnomester]

I have no experience with cheap tube notchers but I do need to notch pipe or drill holes into pipe on occasion and I've just used good quality hole saws.

Starret hole saws ( I think that is what is pictured in your post) come with a data sheet tucked neatly into the box with a list of cutting speeds for different hole saw sizes.

Just use a good cutting compound with them to prolong the saws life and provide a cleaner cut.

Chris

[weezilco]

I have no experience with cheap tube notchers but I do need to notch pipe or drill holes into pipe on occasion and I've just used good quality hole saws.

Starret hole saws ( I think that is what is pictured in your post) come with a data sheet tucked neatly into the box with a list of cutting speeds for different hole saw sizes.

Just use a good cutting compound with them to prolong the saws life and provide a cleaner cut.

Chris

Hey Chris, thanks much. Me being a self-taught mechanical engineer/constructor, I can use all the information, hints & tips I can get.

I'm just a hobbyist compared to most of the real racers around here. Even SE Asian junk tools seem get the job done for me once or twice. With luck, a cheapo notcher will get me through the 50cc bike project.

I'm having boatloads of fun working it all out, anyway.

seeya

-Brian

[gnomester]

I've never built a frame but I'd say the $150 Tube notcher that Hare and Forbes sell is aimed at buyers like you weezilco.

I've only needed to notch one piece of pipe for a job (at any one time) so I have not worried too much about the time needed to set the pipe up in a pedestal drill to make one cut.
I've also needed to use a round file to clean up on some jobs as the cut isn't always exactly round.

...and I've only ever cut round hollow steel and some rectangular section in steel with hole saws as well.
I can't help with how a hole saw would treat other materials ... except for aluminium..... and I would find a good engineering shop to cut and notch aluminium for me rather than butcher it with a hole saw.

Chris