Game on!

[Voicecoil]

I've found time to do a bit more on this in the last few days, firstly got the gantry extrusion fully end drilled and tapped..... it just fitted under the pillar drill with 15mm to spare

talking of tapping I soon realised that there were going to be A LOT of holes to tap and if I wanted to save a lot of time (and avoid w*****s cramp!) machine tapping was the way to go. Tapping machines looked a tad expensive for the moment, thought about changing the motor of the pillar drill to give a quick reverse function, but some bits were on a couple of weeks lead time.... then I tried one of the Europa tool interrupted-thread spiral point taps:

These seem to require a lot less tapping force than anything I've tried before and seemed hence offer up the option of tapping with a cordless drill (which convieniently has a torque limter to stop breaking taps, and a reverse to extract them). In order to keep things straight I added a circular level to the back of an old drill, using the pillar drill and a length of tool steel rod to get it properly level whilst the glue dried.

With this and a known flat surface I seem to be able to tap holes pretty straight and all for the outlay of a £1.80 level off the Bay of fleas; and you can do it in large pieces that wouldn't fit under a normal pillar drill.

[AndyUK]

In order to keep things straight I added a circular level to the back of an old drill

Nice bit of customisation! I've taken to using a guide for my taps to pass through; find a block of something (wood, aluminium) that is about as thick as your tap is long, minus 1cm and the length of the square drive section. Using the pillar drill, put a guide hole through the block - diameter to be as close fitting as to your tap as possible. Now you can place this block up against the surface you're going to tap, passing the tap through for the first bit of the hole - hey presto, nice and straight tapping every time.

[Voicecoil]

I've got most of the pieces machined up now and waiting for the dozy anodisers to do their stuff on some of the beams - whilst it's obviously a home built machine I wanted it too look vaguely OK and I don't really have the space for some 3ft long anodising batths at the mo. Today I finished off making the spindle clamp, I'd cut the outside profile and done the holes a few weeks back, but I've been waiting for a friend to have some free time so I could use his mighty steam-powered lathe to bore the hole. Here it is after putting a 30mm drill through to start things off: And yes, that's a 300mm chuck and it's a heavy lump!

Then it was something like 3 hours gentle boring out, with a few minor hiccups and several Km of swarf - here's the end result:

The internal finish wasn't quite as good as I'd hoped as he had a rather limited range of boring bars and with 80mm of tool sticking out from the toolpost there was a certain amount of resonance going on; never mind, no-one will ever see it, and as long as it grips the spindle I'll be happy.
The reason for making the spindle clamp was initially because I couldn't easily source an 85mm part OTS, then it kind of led to some lateral thinking about how to implement the Z axis with good strength and minimum width - all will be revealed soon when I start putting it together

[Voicecoil]

I've been cracking on with stuff the last few days, here's a pic of some of the parts:

From LHS clockwise we have Z axis slide with clamp sitting on top of the bed cross beams, front bed end plates, Z axis top plate, gantry end plates and the Z axis back plate. Just hit a bit of a snag though - the big bit of plate for the top of the bed has been cut well off square by the folk at Smiths - thus even with the 2mm tolerance oversize by the time it's trued up it will be 2mm short causing a few major headaches - I will be bending their ears on Tuesday

[Voicecoil]

Marking out the bed plate:



I need a bigger surface plate!!!

[AndyGuid]

Marking out the bed plate:



I need a bigger surface plate!!!

As a pen-pusher, I'm guessing that your method is a very accurate way of manually Marking Out Using a Surface Plate and Height Gauge ?

[Voicecoil]

Yes, I bought the height gauge and optical centre punch for this project and I've been suprised at how accurately you can do things - I reckon on smaller pieces the max error isn't much more than +/- 0.1mm and maybe twice that on longer bits: quite a novelty not to have to file out holes to get things to line up! Mind you, when you think about it people were making accurate stuff 60 to 70 years ago before CNC was even thought of, so it had to be possible.