a Steel Box Section Build with SBR20 & Ballscrews Plus a few questions

[EddyCurrent]

Take a look at this diagram, you can see that in your design the spindle would hang out from the gantry well past the bearing blocks.

http://www.cncroutersource.com/do-it...NC-router.html

It's usually regarded as X being the rails mounted on the frame, Y being the rails mounted on the gantry, Z where the spindle mounts.
Two motors on X works fine, just remember you would then need to, rate your power supply accordingly, purchase another stepper driver, add 2 home switches. It's generally regarded as advantagous to connect the motor to the ball screws using timing belts, the pulley sizes can also be selected to increase or decrease speed so that your stepper motor is working in it's optimum range while the cutting speeds are also optimum.
You might need this as you indicate 1605 screws all round, I'm using 1610 on X and Y which seems right using 1:1 ratio of pulley

[Clive S]

Rob Welcome to the forum. Please don't buy anymore kit until you have your design finished its the biggest mistake people make. Ask as many questions as you can (a few at a time is better) and expect a bit of leg pulling but you will get all the advise you need on here.
There are generally two ways to drive the x screws either with one motor and a belt going to the other screw or using two motors one for each screw, there are for's and against both system. But they both function ok.
You will need more bracing of the frame that what you have. ..Clive

[grain_r]

Thanks guys for that, I have put the spindle so that it will go past the frame so that I can cut on the end of material for letting on the sides of work, Although I suppose I am stopping me from being able to cut sheet as long as I would otherwise be able too. I have thought about moving the rails back a little and then making a clamp so that I could lamp it to the internal 'Y' support beam.

I thought I might be under building on the supports. Because I am going through the centre vertical beam I will have to have a change to get the support in. would it be best to brace from corner to corner or is it as strong if I triangle off the corners

I seem to buy the stuff and then learn and I have after many years started to come out of that routine things always work out but always a more difficult path and more stuff for the spares box.

[grain_r]

Hello I have been doing a spot of re-design for the bracing Hopefully I haven't gone the other way with it now. I was trying to use a little less steel to keep the cost down but I would certainly rather have a stronger machine.