Re-Building Suregrave CNC

[PeterC]

Hi All

Many thanks for the heads up on the gantry strength.

I’m going to be setting up the cnc on it’s stand over the next few days. I might get a dial indicator setup on it and see just how much flex it has. I’ll also look to see if their is any way to beef up the gantry / z axis if it flexes too much.

The old mount for the dead 240v spindle is only about 20mm high and held onto it by the collar only. I was already thinking I’d have to try and make a new mount somehow as the old spindle seems a weird size and I’d think I’d struggle to find another one the same.

Luckily I have a friend with a milling machine, who likes a challenge and accepts beer tokens!!!

Either way, I do like the idea of using a vfd/spindle setup rather than a regular router. Not so much for the cutting ability, but more for the noise.

I’ve seen some 800w air cooled spindles with fans on the top. YouTube gives mixed messages about these, so i’m not sure which way to go.

My eventual goal is to be able to cut up to 18mm mdf and ply, up to 5mm Perspex and polycarbonate. In an ideal world I’d love to be able to cut 6mm aluminium plate but it’s not the end of the world if this is a step too far.

I will post some photos when I can.

Many thanks

Peter


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[PeterC]

Hello All,

Made good progress today. I built an additional bench to hold the CNC. I had to cut into my outfeed table / workbench but I think it's turned out well. When not in use I can fit a board over part of the CNC so I can use the table saw outfeed, I simply have to lift the board out to expose the whole CNC.



Looking at the strength of the X axis. I agree that the axis looks weak, there is nothing support the linear rail against any deflection. I have had an idea to strengthen it up. I'm going to get a length of 28mm square steel tube. My plan will be to bolt this to the back of the linear rail and tie it back into the gantry supports (which are ironically very well built). I'll have to cut a little bit of the thin black plate away t(but this is just cosmetic) to allow the tube and linear rail to bolt into the supports. In one of the attached photos I'm holding a piece of section to give you an idea. Would like to know what you think?

I didn't get time to look at the spindle, that's for another day!

Thoughts, comments or suggestions always welcome!

Peter

[JAZZCNC]

My honest opinion is that you are wasting your time with this gantry setup if you want to use it for a router as it's just not strong enough and certainly would be wasting your money trying to fit a 1.5 or 2.2kw spindle to it. The Single narrow beam just doesn't offer enough support for the Z-axis, really you need another above the lead screw so it offers support for the Z-axis backplate.