time to gather parts for new machine

[MikeyC38]

Hi Deano.
I thorughly agree with JazzCNC and Jonathan about drawing out your design with a CAD package. You can see this from my thread here http://www.mycncuk.com/forums/showth...gn-Build/page4 and it allowed me to get good advice from the guys here on the forum who have learnt the hard way! A picture tells a thousand words!! A 300 mm ballscrew does not have a thread length of 300mm - it is about 200 once you take into account the end machining to fit the bearings at either end. On my Y axis, this clearly showed up when I did the drawing. I use TurboCAD Platinum Pro 15 which I got from Paul Tracey http://paulthecad.co.uk/ at the Model Engineer exhibition some years ago for a fantastic price (very much less than retail!!). It does solid modelling which means when you draw the ballscrew, bearings etc, you can "assemble" them together just like real objects. Some of the stuff like the BF/BK bearing blocks, stepper motor couplings I got off the internet already drawn as 3d objects, so it was easy just to use them. Also as CAD is / will be part of my workflow to use the machine i.e. CAD draw object send to CAM software to produce toolpaths and tool selection then to CNC, then for me it is time well spent.

There is quite a step learning curve in using these programs (Google Sketchup is easier to get to grips with) so unless you are in a hurry, it makes you think through every stage. My mantra is "measure twice cut once" so doing the drawings etc will hopefully help me avoid some expensive mistakes.

All the best with you new project!

Mike

PS Also got my rails, ballscrews, bearings couplings from Chai at Linearmotionbearings2008 on ebay. Fantastic price and great service. Everything turned up within 10 days and was straight.

[deannos]

Hi Mike,

I have been playing with sketchup and i can just about get a square on there at the moment. I'm in no real rush for a build as my work shop is basically out side. I'm thinking its best to start with the ballscrews and then design form those, i.e use the set lengths, or is that the wrong way

[MikeyC38]

Hi Mike,

I have been playing with sketchup and i can just about get a square on there at the moment. I'm in no real rush for a build as my work shop is basically out side. I'm thinking its best to start with the ballscrews and then design form those, i.e use the set lengths, or is that the wrong way

Hi deano
This is what I ended up doing, as buying the ballscrews, ball nuts, bearings and couplings from Chai's standard offerings seemed the cheapest way. I had a rough idea of the cut area I wanted - had to cut guitar bodies and guitar necks which are approx 575 - 660mm long and then estimate how much is lost from the X and Yaxis due to the gantry.

The guys on this forum were great in advising on suppliers they had used with success and on material sizes. On my x axis (longest) they are 20mm dia supported round rail and 16mm dia rails on the other axes.

BTW I've started playing with Sketchup and found a great set of tutorials here http://sketchupforwoodworkers.com/

Regards
Mike