HB2 Ramblin’ Update

I have been spending some more time with my HB1 (Home Brew) engraving machine. I have been taking careful measurements of the movement of all the axis. In an earlier post I reported that there was a problem in the Z axis “dead-band”. As I have observed and measured yesterday, the backlash in the other two axis although not horrible are nothing to brag about either. This drives me to thinking about why I built the machine in the first place.

I was influenced by John Kleinbauer’s web site on building low cost CNC machines. I ordered and built his controller and bought a set of drawings. I was influenced by his concepts but not so much as to duplicate his designs. John is just a bit of a weird duck but he is sincere. Appearing public on the web is quite a challenge in time management. I believe the HB1 is every bit as accurate as John’s designs. I believe John has provided a path for a lot of folks to do more than as he calls it “spin motors”. His web site is a good place to check out low cost CNC.

That said, Having HB1 operational within a few hundred dollars budget is a great introduction to machine design and construction. It is a good operating machine but can not be used where 0.001″ accuracy is required. I won’t be carving jewelry designs, but that was never the intention. Simple wood carvings come out well.

The key to the new design for the HB2 is intention. Just what do I want the machine to be able to do for me? The wrong answer is “everything.” I have spent a lot of time deciding on “purpose”. I have invested in Vectric software as that product has led me to discover my purpose. Accurate relief carving, small signs, 2D cutouts, panel engraving are my targets for the new design. All this requires a large working area for the cutting tool to access.

Size and sound levels are a big consideration for this machine. I do have a limited space and I live in a nice residential  area. I do not want to be running a screaming router for hours on end cutting a large project. That work belongs in a commercial area or inside a sound proof enclosure, probably both. I am able to run 10,000+ rpm on a Taig spindle with very little noise, so that is one solution.

The Taig mill is a very good tool for small engravings. It has all the speed and accuracy required. It provides a bit more usable area than the HB1. Therefor the Taig actually makes refining the HB1 unnecessary. I plan on adding a surface plate on the bed of the Taig mill for easy holding of wider materials. The difference is the investment in the Taig in it’s present state is 10X that of the HB1.

So HB2 is being designed to provide the accuracy of the Taig with a lot more surface area available for the work. It will not be so big that I lose a lot of shop space. However, it won’t fit here in the picture where the other machines are located. My sketches are showing a 24×24 to 24×30 working base size. Z height is currently plotted at 6 inches. The spindle will be the Taig with ER16 collets and also the smaller size routers. The plan is to experiment with various spindles. Dual drive Y axis is being considered because of the width and the off center Y axis center type screw loading when the spindle is full left or right, a lot of details to consider. Stay tuned. ~ Dan’l