Strength wise, not sure. I use v-rail to help keep dust and debris from fouling the track where the wheels run and effecting the quality of the cut. Plus since the v-rail is mounted more towards the outside of the extrusion less spacers are required to get the necessary clearance for the gear rack which equals better rigidity. I tried the original Ox design with the belt and wheels in the groove, it required a constant effort to keep it clear.

Gerald

 

Thank you for the kind words. The V-wheels do contribute to flexing quite a bit. I will probably redesign it at some point to use HiWin or THK linear rails. I wanted to keep this machine more affordable for the average user, linear rails add a lot of money to the build. I push this machine hard a lot just to see where the weak points are and what improvements could and should be made.

So far i'll be satisfied just changing out the racks and steppers on the Y axis and installing new wheels. But I do see linear rails in the future for this machine and my Joes Evo.

You should check out the build Steve Spenceley was working on, very rigid design.

Linear Rail OX

Again thanks,

Gerald

 

Sorry about the absence. To be honest I never really became proficient cutting 6061. I was able to get to a point where it was working pretty well but I still wasn't happy with the results. The bit I finally settled on a .125 O-flute chinese bit. They seemed to work as well as the Toolstoday bits and Onsrud bits. Dry cutting didn't work as near as well as a mist. I'll have to pull up some old files for you and see what the feeds and speeds were that I was using.

I am prepping to do a full tear down and rebuild of this machine, I have numerous wheels on the X cracked and/or split that need replaced and i'm also swapping out the Y gear racks to 20/20 1/2" wide racks with more powerful steppers. After I do the rebuild i'll be more then happy to check that for you. My machines a bit wore right now so i'm sure the numbers wouldn't be good. Just send a photo of exactly how you would like to check it and i'll do my best to accommodate..

Thanks

Gerald

 

Actually i'm looking forward to the tear down. I haven't had to do anything major except change all the Y axis wheels at one time, other than that it's been pretty solid.. The tear down is really to just do some routine maintenance and upgrades..

I'll test mine when I get it back together and see what the results are. I was just thinking, isn't 5 lb's a bit much though for a side load, i'm not sure what your running for DOC but it's usually pretty shallow right, shouldn't be much side load on the bit I would think. Or am I missing something, just curious? Are you running the extreme wheels or the delrin? Also what size bit's are you running, O-flute or 3 flute?

If you put the dial indicator on top of the gantry above your hand facing the carriage does it show deflection going the opposite way? Just wondering if the carriage is twisting/rotating due to wheel flex..

I might just redesign the plates on mine for THK or HiWin linear rails, eliminate the plastic wheels all together, not sure yet, it's a pretty big expense for a machine that does nothing but cut wood...

Send some photos over of your machine if you don't mind, looks like a great build i'd like to take a look..

Thanks

Gerald

 

You're most likely right about the deflection on a standard mill, but this stuff is no where near that quality. But I understand where your coming from, the more rigid the machine the better cut quality, tool life, etc.... Honestly with the wheels, I've never been a huge fan. I have always found deflection no matter what in amounts more than what I would like. I think switching to all hardened V-wheels would help immensely, but without hardened v-rails they would wear out way too fast. My other machine uses hardened V-wheels running on angle iron for rails, very rigid machine.

I will find a way to measure the springs for strength when I disassemble the machine, I just picked them up from the local Home Depot if I remember correctly. I tighten mine down until all the backlash is gone then go about 1.5 turns more to pre-load the spring.

Just wondering but how many wheels do you have on the X gantry carriage? Are you running the Ox style Z-slide, with wheels and such?

I'll be more than happy to help out in anyway I can. I found another supplier for spur gears so hopefully all my parts will arrive shortly and i'll get started on the tear down next week..

Thanks

Gerald