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masinecc
06-02-2016, 10:57 PM
Do u thing i nessecerly need to do a face milling of my 80x80x5mm steel tube to mount the helical rack M1.25?! If i mill it lets say 1.5mm the wall thickness will be 3.5mm which is not enough to screw the rack on the tube. I plan to weld a steel piece on the top of the tube and than face mill it and mount the rails, but i really dont know what to do with rack.The gear and the linear rail are fixed, and i can not move them and i only can play with the steel tube
1752717528 Looking forward for some advices.

routercnc
06-02-2016, 11:29 PM
I've not used rack and pinion myself but guess the surface for the rack needs to be fairly flat. If you machine a flat section then you could always add a piece of flat bar on the inside of the box section to compensate. Go for 5-6mm thick and you will have plenty to thread into and it will give extra support

masinecc
06-02-2016, 11:39 PM
Thats what i was thinking about, that was one of my options. Thanks a lot anyway.

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masinecc
16-02-2016, 03:57 PM
I found machinist who ask for 200 Euro for face milling on steel plates for mounting rails and rack. Its kinda too much. Any cheaper but good working17607 solution ?

mekanik
16-02-2016, 04:52 PM
I found machinist who ask for 200 Euro for face milling on steel plates for mounting rails and rack. Its kinda too much. Any cheaper but good working17607 solution ?

Just a note but i think you would be better having the rack the other way round (ie flat face to top) as you have it shown the gear and rack are going to get contaminated with all sorts of crap.
Perhaps you could fix the rack direct and adjust with spacers @ each fixing point, you could clock it in using a fixture on the support rails(gantry would be ideal)
Regards
Mike

JAZZCNC
16-02-2016, 05:04 PM
You don't need a ground or even machined surface just so long as it's resoanble flat and stright.

Mekanik is correct that you don't want the Rack facing upwards as it will soon fill with debris and you'll have allsorts of trouble. Idealy you want it facing downwards and the Pinion spring loaded into it. This way if your surface isn't perfectly flat the pinion is still fully engaged.

Could have it on it's side but still you'll want some form of guard above to stop debris falling into the rack

masinecc
16-02-2016, 05:54 PM
I had it already fix, but havent post it here. Here how it looks now :) 17608