Confusion over carbon tubes

Hi,

First of all I apologize if this is a stupid question.

I need help clearing up some confusion I have regarding carbon fibre tubes with traxxas rod ends. Basically I am building my first delta printer based on the Griffin printer, I have purchased some carbon fibre tube (6mm OD x 4mm ID) and Traxxas 5347 Rod Ends. I have tapped some threads into the rod ends and purchased some m4 threaded and inserted it into the newly threaded rod ends. Up until this point everything was running smoothly, I watched several videos on how to thread the tubing only to discover that there wouldn’t be any point threading the tube as I can insert the threaded rod (with the rod end) into the tube without any pre tapping. Here is where I am stuck, with the tube having an ID of 4mm and the threaded rod in the ends being 4mm the rod was never going to be bigger enough to require me to tap the tube. Have I made a mistake somewhere along the line? How am I supposed to attach the rods ends to the tube? I don’t like the idea of just using glue as I will be using a heated bed and wouldn’t want the glue to soften / melt due to the heat?


Thanks

Quote
Make_3D
Hi,

First of all I apologize if this is a stupid question.

I need help clearing up some confusion I have regarding carbon fibre tubes with traxxas rod ends. Basically I am building my first delta printer based on the Griffin printer, I have purchased some carbon fibre tube (6mm OD x 4mm ID) and Traxxas 5347 Rod Ends. I have tapped some threads into the rod ends and purchased some m4 threaded and inserted it into the newly threaded rod ends. Up until this point everything was running smoothly, I watched several videos on how to thread the tubing only to discover that there wouldn’t be any point threading the tube as I can insert the threaded rod (with the rod end) into the tube without any pre tapping. Here is where I am stuck, with the tube having an ID of 4mm and the threaded rod in the ends being 4mm the rod was never going to be bigger enough to require me to tap the tube. Have I made a mistake somewhere along the line? How am I supposed to attach the rods ends to the tube? I don’t like the idea of just using glue as I will be using a heated bed and wouldn’t want the glue to soften / melt due to the heat?


Thanks

Usual method is to thread the screwed rod into the Traxas joint (it is easier to use socket grub screws (Setscrews) for this and then you glue them into the CF tube using a Good Epoxy resin (try to use a slow set one rather then a very rapid one) you could get away with a 5 minute one but leave each rod on the jig for at least an hour to cure (full strength is normally acheived after 24 hours) which should not melt/loosen at the temps we are talking about.

You would be well advised to make up a jig and then do one rod at a time to ensure you get them all exactly the same length.

Several ways to do this

a) if you already have access to a working printer you can print 2 of Delta rod Jigs and mount them to one of your extrusion whilst you make them off

b) Mount 2 M3 screws/setscrews into something solid so that you can slide the ball joints over them.

HTH

Doug

Doug

I second Doug's advice, that's how I assembled the rods for my delta. I used slow set epoxy (Araldite Standard), and left each newly-assembled rod in the airing cupboard for 8 hours, before removing it from the jig and assembling the next one.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

Thanks for the reply guys,

So it doesnt matter that the CF tube isnt threaded, the epoxy is enough to hold it all in place? I will get some strong slow set epoxy, I was abit concerned about relying on epoxy alone to hold the arms together as I had used epoxy on the X axis of my i3 and during long prints it would soften and end up detaching itself from the part.

I do have access to some 3D printers and will print the jigs off and see how it goes, I am finding it abit difficult to cut the CF tubes so that they are all identical.

You don't need the cf tubes to be cut identically, just close. Adjust the jig length so that there is about 1mm gap between the Traxxas ends and the cf tube ends.

Edited 1 time(s). Last edit at 05/08/2015 03:22AM by dc42.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].