Adjustable mirror mount, The first.

 

This is the first one I'm making and it is for the gantry, which seems to dictate a few different heights on other parts of the machine.

I mostly copied this design from mirror mounts I saw for sale on Ebay. The plate with the mirror attached is pulled tight against the thumbscrews by a pair of springs. It all pivots on a ball bearing.

 

I decides to go with 25mm diameter mirrors because it allowed for the best chance of alignment to happen at all!

I started by using a 1" hole saw to cut the recess for the mirror to sit in. I just cut 2mm or so in to the 6mm thick aluminium.
Then I drilled out the rest of the material to a 22mm hole. It wandered all over the place as can be seen from the back view. Not too big a deal in this case, just looks poor.
For the ball bearing hole and thumb screw holes I used the cone of a centreing drill. it gives a chatter free conical hole, unlike a counter sink in my drill press.
Perhaps not the best cone angle.
I'm using a 6.5?mm dia ball bearing here. It was just one I had lying/rolling around. It seems okay.

The adjusting screws are M4 by .5, the fine version of the standard M4 thread. I did so because I read someone giving out about a similar set-up which was using a standard thread here and it was very difficult to get an accurate adjustment with it.(this was on a commercial, cheapo Chinese laser cutter.)

I cut the springs from a long spring I had and bent the loops up. They work well. 4mm dia with wire of .9mm I think.They are held in place with TIG filler rod pins.
I made the thumb screws on the lathe. Turned from 6mm brass rod, down to M4 by .5!(with a die). I should have faced off, then centre drilled the ends of the bar before I started, as I need to put a small ball bearing into the end of the thumb screw to stop it biting into the aluminium.

The mirror will be held in place with a ring held in with three M3 socket heads. To be cut on my router from 2mm aluminium sheet.

A lost camera, found again.

I have been working away the last few days without taking any pic's. So now, as I found my camera again, there is a bit of progress to be shown.
First here is a picture of the frame of the cutter itself. I was just laying it out to see the size and make a few decisions! Again the size being dictated by the belt length.(by the way, if you click any of the pictures, a larger sized slideshow should come up, nice!)

You can see the first of the X axis' supported rails here. The other is the gantry rail temporarily. I cut the box section with the bandsaw and finished it with the flycutter on the lathe. I really like the fly cutter, it such a lovely finish. Great for butt joints.

Below is the linear bearing and belt setup for the gantry. The "belt through the hole" idea is from the LightObject design. A nice space saving idea.

It allows gubbins to be directly above the bearing and belt. The clamping plate setup is the same as the gantry. One fixed and one adjustable.

In the picture above you can see the bolt holes for the motor mount and the access for the linear bearing bolts. Mine is off to the side a bit, due to the fact the I had to bolt the bearing and spacer on from above.
Here is a wide of the gantry minus the rail, motor etc.

Just tonight I finished drilling the 8, 22mm holes in the bearing blocks for the X axis belts. Each hole took 8  different sized drill bits. Spotter, centering bit, 4mm, 7mm 11mm 13mm 16mm 20mm 22mm. It makes it time consuming but the way the hole is still in the right place at the end makes worth while. More on that in the next post.

Leetro Machine Controller Arrival!

I splashed out when I saw a Leetro laser cutter machine controller for sale on eBay.
It's one of these!
I was origanally going to try to botch my way through it with Mach2/3. But I saw this and decided it was too good an opertunity to pass.

I have had some success in past using a diode laser on my CNC and using the 0.0016 as my cutting depth and using the direction pin as digital on/off for the laser. The process is detailed elsewhere on the web and a search will bring it up so I won't explain here. Worth looking into to play around with a diode laser on a cnc router.

Another View

This post is a continuation of yesterday's.

Another angle on the gantry slide.
This shot is to show the bearing that supports the slide, as the linear bearing doesn't do anything to stop the slide from rolling on the rail. I put in a 608 (skate)bearing to roll along the top of the box section.I'm relying on gravity to hold it down...
If you look closely, the vertical part of the L angle is not parallel to the box section. The 608 bearing is too high. Its out by a mm or so. Bummer. I'll have to mill out the hole and rely on the countersink to keep it in the right place.

 Here is a wide shot of the work so far. I'm off for 8 days, so no posts for a bit.

 

Clamping plates 15 3m.

In this post, clamping plates and gantry assembly and other very very interesting things.
Lets start with blurry picture.

 The point I was trying to illustrate was the bevelling of the edges of the slots. I wanted the belt to sit in as deeply as possible, so the corners had to go. The piece of Al. above 10x10x50mm with the slots being 1.6mm wide 1.5 deep and 19mm long. On 3mm centres to match the belt...
I cut it on my CNC. I cut at .6mm per pass 100mm/min with 3in1 as cutting fluid.
Once I was happy that it was working I went ahead and cut the other 5.

I'll chop them up with a slot saw on the lathe.
Here is the slide on the gantry. The linear bearing arrived! I did notice that you must tighten the two grub screws in them to fix the bearing into the mount.

The belt clamp on the left is fixed and on the right is adjustable to tighten the belt.

A Hard Case to Crack

Good progress today. Linear rail for gantry drilled and tapped and gantry motor mount made!
I'll start with the motor mount as its very straight forward and need little explaining.
Here is a pic!

Its 6mm thick. I had to put it in the 4 jaw chuck on the lathe to cut the big hole.Drilled the 4 holes to 4.2mm and tapped M5. I've yet to drill the holes to mount on the gantry. I need to get the linear bearing first...

But the big thing today was the supported rail for the gantry.

 I'm going to go into a bit of detail here because

 it was a pain to get this done untill I got the knack!

 (and this might help someone trying the same thing)

In this project I'm using 16mm linear rails. They are case hardened, which means no drilling into the surface.
But...below the surface is normal mild steel! So I can work that easily if I can just get to it!
If your drills or taps touch the hardened steel the will snap.
So follow the steps below and your laughing!

1. Mark your drilling points with a permanent marker (don't bother trying to scribe a mark at this stage).

2. With an angle grinder, grind the spots you've marked. Be careful, try to stay inside your support width, 8mm in my case. The point here is to get the centre of the cut to be through the case hardening.

Here is the first cut

3. Remeasure, scribe and centre punch your drilling points.

 4. Get a tile drill at least 2mm larger that the thread diameter of your tie down bolts. M6 in my case so I'm drilling with an 8mm here. Naturally you want to use lubericant of some type here... an interesting side note, normally these drills are used for tiles and glass and water is the lubericant. But I have a suspition that the water is a coolant not a lubericant.

I noticed that it wasn't untill the oil I was using was pushed out of the drills path did it start cutting properly.

5. Drill with the tile drill untill you are at least 1mm larger than you tap diameter. So I drilled in to 7mm or so!
Now you can go ahead with a nornal tapping drill size as you are throught he case hardening...

 6. Once you've done one hole, go and tap it!
      You see the gap between the tap and the case hardened steel.

 Now scew in a short length of threaded bar. This will help ensure all the other holes are on the same axis!

7. Go ahead and drill the other holes. Tile drill then tapping drill always using the threaded bar as a guide to the alignment.

When you have all that done mark and drill the U channel. It will all line up... and you get:

Lovely.

Good money for scrap metal

Here are some photos of progress!
Below is how the bottom frame will be held together. I am dubious about how good this method can be as there is no triangulation. The Aluminium here is box 50x50x3 and angle 80x80x8

 I'm not sure exactly how long the Y axis will be it is dictated by the length of the belts, plus whatever they are tied to, ie: the gantry.

 This is in no particular order, I'm kind of working on the whole thing at the same time. Its the way this has to happen as far as I can see. Every part has an effect on the other parts. Its messy!
Below is the gantry toothed pulley. 15 3m 24 size. That is to suit 15mm wide belt, 3mm pitch, 24 teeth.(thats a mouthful)

 I was out on a film shoot and I spotted the camera dolly was on round tracks, supported on a U channel, not a solid block. It must be stronger that I guessed. I used solid bar on my last supported rail effort for my CNC router.

 Here is the 1800 3m 15 belt from Polybelt in th US of all things this is dictating the size of my cutting area.

Its probably going to be under 900x900mm

Thats not the end of the world. Its also a floor space issue!

 There is the Y axis motor. Salvaged from an old photocopier, years ago! I drilled out the pully and pushed it on. It was drilled out on the lathe. I'll eventually put a grub screw into it.

 I'm really waiting for the linear bearings to arrive now. I don't want to do any work assuming they will match their description regarding tapped hole positions. C'mon China Post!

Not another project!

I have been thinking about making a CNC laser cutter for a while now and was inspired to start when I saw this laser cutter XY set up.
Its simplicity of design is what struck me and the fact that its made of fairly standard components.
So thats the design I'm going to follow morealess.
I'm keeping this blog as a record for myself as much as for anyone else who might want to look in!

On my shopping list so far are:

3X16mm open linear bearings (Ebay, china.)
3m 16mm round rod/shaft to suit above.( Reliance bearings JFK Ind Est, Dublin.)
4m 50X50X3mm Aluminium box section. (Miko Metals, Cork)
500mm 80X80X8 L angle.(Miko Metals, Cork)
2m 25X50X3mm Aluminium box section.(Healey's JFK Ind Est, Dublin)
6 3m24-15 timing pulleys (Rotate Ltd, Dublin Ind Est)
3 1800mm 3m-15 Timing belts (Poly-belt, USA, Internet)
4 flexable shaft couplers (Ebay, China)
2 Steppers(1 I have from a photocopier, 1 probably from Hobbycnc, USA)
Misc bolts!
Laser 40watt plus power supply (Ebay no doubt)
Mirrors (Dont know yet)
Mirror mounts (Dont know yet)
Cutter head (Dont know yet)

There will be plenty of photos along the way too...