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Off Topic Hobbies => Mechanical Engineering => Topic started by: beanflying on April 08, 2021, 07:35:29 am

Title: Rack and Pinion solution for V-Slot Aluminium
Post by: beanflying on April 08, 2021, 07:35:29 am
No home for this in particular and it is a new product to me. There has been bolt on Metal options for a while but this is now a lost cost alternate for lighter duty applications. So if you dislike long belts on your CNC projects look it up.

Precision plastic and inserts into V-Slot Aluminium https://www.makerstore.com.au/product/gear-m1-int-500-d/ (https://www.makerstore.com.au/product/gear-m1-int-500-d/) should be available elsewhere too. Downside is locally they only have 1/4" Pinions to suit NEMA 23 Steppers but I would most likely be running a reduction drive to this so adapting to NEMA X would be easy. Possibly ok for lighter duty routers too but generally there are better options with Ball Screws.

Redesign on my Foam Cutter project is a bit of a no brainer as it simplifies the design a lot and removes 3m Belt runs and the stretch issues that go with it. Seriously now considering a re design of my 1200x800 Laser cutter even though I have all the bits in stock for it.  :-//

(https://www.makerstore.com.au/wp-content/uploads/2020/08/GEAR-M1-INT-500-03.jpg)
Title: Re: Rack and Pinion solution for V-Slot Aluminium
Post by: AmnevaR on April 08, 2021, 07:24:39 pm
An interesting product indeed. But I can't figure out how to avoid backlash without some ''tension'' spring.
There is of course  a "driven nut" design (https://www.linearmotiontips.com/whats-the-difference-between-a-ball-screw-spline-and-a-traditional-ball-screw/ (https://www.linearmotiontips.com/whats-the-difference-between-a-ball-screw-spline-and-a-traditional-ball-screw/)), really small backlash with it,  but the cost for a long screw will go through the roof :)
Title: Re: Rack and Pinion solution for V-Slot Aluminium
Post by: jpanhalt on April 08, 2021, 09:02:55 pm
Wonder whether made for a worm gear to minimize backlash and improve holding?

https://www.youtube.com/watch?v=FTKTd3EfORo (https://www.youtube.com/watch?v=FTKTd3EfORo)
Title: Re: Rack and Pinion solution for V-Slot Aluminium
Post by: beanflying on April 09, 2021, 12:21:05 am
Backlash can be controlled by the depth you insert the pinion into the rack. The Pinion teeth are not flat cut as per below so adjusted properly are on the back and front face of a rack tooth at the same time.

Side note Module 1 like this stuff it actually Pi (3.1415926.......) Pitch so drawing it 'accurately' in CAD kind of sucks due to rounding issues. The drawing and dimensions on Makerstore are poor approximations of the maths if you try and use them in a model so tweak as needed.

(https://www.sdp-si.com/resources/elements-of-metric-gear-technology/images/Fig2-7.jpg)


Title: Re: Rack and Pinion solution for V-Slot Aluminium
Post by: beanflying on April 09, 2021, 03:41:07 am
Possible solution/idea for a Maker Rail/Plate build. Two 6mm high spacers above the wheels and a 3D printed Housing containing the pinion and two 1/2 x 1/4 R188zz Bearings sitting on a 1/4" shaft. In my case I am going with a 3mm Stainless plate or if you go with Aluminium with a cutout then 5-6mm might be needed to keep the rigidity across the cutout. M3 screws and knurl nuts for fasteners.

Quick check of the housing it will print fine without supports due to tweaking a few faces internally.