Tube notching ?

[dobbslc]

I'm preparing to make a seat sub frame for my bike out of ERW pipe, I've had a go at notching it on my lathe/ mill but I'm having trouble holding it and getting it centred correctly. It's 21mm OD x 3mm wall ERW pipe. I'm thinking about getting a tube notcher off ebay as it self centres and has a proper pipe clamp on it,
I'm assuming I need a 20mm hole saw for 20ish mm tube as the fit up isn't great so far.
any thoughts or advice welcome.
Rob

 

[rory1]

If it's a one off Half round file and a hacksaw will make short work of that sized material

 

[addjunkie]

Thats what i use too........cut two 45 degree angles then file....

 

[Jim Davey]

Flap disc, file, anything that works if there aren't too many joints to do.

 

[chevy2]

I've got this one, but then i do a fair bit of tube work on chassis's and cages so its worth it to me,
this is a mid priced one,
i've used the cheaper ones and they're... Cheap

 

[chevy2]

To add, if you've got a chop or cold saw you can do tube tube notches on them,
Works out well on 3mm tube if its gonna be migged as it leaves a vee for welding,
i found that on 42mm tube if doing a notch that goes at 90 deg to the other tube then set your coldsaw at about 42 deg,
do two cuts to form the notch and leave about 10-15mm of the square cut if this makes sense?
very minor filing or sanding will get a real nice fit for welding.

 

[Jim Davey]

There are some good online guides for tube notching, the guy is a bit irritating but he gives some handy tips.

 

[chevy2]

Only had a quick brouse of the vid and noticed he's using those magnets when he adds the first tack,
i only use them for setting up as them buggers are great at sucking the weld arc towards them, arrrrgh.

 

[Jim Davey]

Yes, arc blow is a big downside of magnetic clamps.

 

[Kent]

Mag clamps are fine for getting a tack or two on. Once tacked you font need the mag clamp anyhow

The video is quite good I think and he didnt get up my nose personally
The only thing I would say like so many younger guys does he not realise how much easier things are with hand operated tools

Erw is easy peasy to work with files. Hacksaws etc and your far less likely to take too much out in one go

 

[Ton-up]

I'm preparing to make a seat sub frame for my bike out of ERW pipe, I've had a go at notching it on my lathe/ mill but I'm having trouble holding it and getting it centred correctly. It's 21mm OD x 3mm wall ERW pipe. I'm thinking about getting a tube notcher off ebay as it self centres and has a proper pipe clamp on it,
I'm assuming I need a 20mm hole saw for 20ish mm tube as the fit up isn't great so far.
any thoughts or advice welcome.
Rob

l

Two ways that I have notched jobs are either - use a normal hole saw in a pillar drill. The trick is to put a piece of MDF or simular each side of the tube in the vice to centre the saw. Bit harder with angles as you need a tilting vice or machine table.
I dont know what lathe you have but the other way, which the largest I have done was on some 1" dia, 3/8" wall stainless tube, meeting1 1/4" dia. I did this on my lathe by using a 1 1/4" end mill held in the chuck and made a holder for the tube to be notched on the toolpost. Obviously, centre heights and angles can be changed on the toolpost.
The lathe ran on the lowest speed/feed and it didn't even know it was doing it!