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jrob3rts
11-10-2010, 10:51 PM
Hi,

Not much of a build log for now as I have no pictures. These will follow shortly.
I asked a few weeks back for some advice, however responses were slow so I did the usual thing and tinkered on a few ideas. I finally decided to build a machine from scratch, primarily using a method described on buildyourcnc.com. Why? It's cheaper, and means I can configure it a little bit more for my needs.

I ordered a load of MDF, loads of skate bearings bearings, bolts, alloy angle and so on. My contraption started to take form 2 weekends ago.

My X axis bearings went like a dream, sadly Y and Z were somewhat different, these ended up being rebuild as I was not happy with the results.

The design is fixed bed, with a moving gantry. I originally had a 900X600 bed, but this curved and I have changed this for a 550x600 bed, which is moisture proof MDF, hoping it'll last a bit longer. Sadly however the change in size has meant that although I have approx. 400mm X axis travel, the way in which the machine is designed means that I am limited to approx. 200-250mm cutting. That will change as I start to play a bit more but for now is ample.

I am using an eBay bought set of steppers, controller and PSU. The 1st controller fried, I actually had a hole in the X Axis chip so that has been replaced. Initial thoughts were bad, however with some tuning and careful re-allignment, I have made these work as expected.

Drive is via M8 threaded rod, I am using a combination of delrin and long nuts for the drive nuts, backlash will be evident, however some of my initial cuts will utilise the accuracy of said machine (well as accurate as it is) to recreate some parts.

Initial thoughts are that skate bearings and alloy angle are not an efficient method. There is too much stress on the supports, and in time I expect wear to kick in. Sadly with British Weather, MDF doesn't stay straight without extensive re-inforcement for long.

My router is a Rotozip, well I have left that for now, and am using a B&Q Branded Rotozip, which is useful because it came with a spare mounting so the mount, albeit basic was easy to build.

I'll get some pics up, I started to make my 1st cut tonight using a template from the internet. It is very slow, a few steps a sec I think, so will need to look to speed that up.

For now, it will fit my requirement.

James

jrob3rts
12-05-2011, 05:44 PM
Well, it's been a while. So here is my update.
During a move, I dismantled my machine and decided to decimission it. I have since bought an off the shelf CNC from
Marchant Dice. Desperate to use it but it's been moved to France where I shall be moving to in the next 2 months.
So, I have a machine called "A3" which is one of Kevin's larger hobby machines.
Will update when I next see the machine, and for now will be looking out for some suitably mills for learning and practicing so expect a few question floating around soon.
James