I got to spend some quality time with the CNC router today. The picture shows about half of the parts necessary to build Brian Law’s Clock 22. I finally have a working setup that is easy to use! This is mainly because of the new CAM-BAM software that somebody recommended. I highly recommed it for DXF to G-Code conversion. Especially for routers like this one that run LinuxCNC. It is super easy to use and easy to insert the holding taps that keep the part from lifting up after it is finished.
I hope you’ll keep postign as you build the clock! I too think Cam-Bam is great!
Very nice and such great detail. Except for the lack of burn marks, one might think this was laser cut.
I’ve been working with cambam and heekscad/cam, both of which offer a ton of nice features. I’m hoping the cam extensions for freecad develop into something similar.
Do you mind sharing the DXF files? =)
…Or could you please link to the design for that particular clock. It looks nice and well thought and my CNC needs something to do when its finished in a few months.
Sorry, I can’t share the DXF. They can be obtained at:
http://www.woodenclocks.co.uk/
I am a big fan of Brian’s escapements and Clayton Boyer’s vast array of designs. All of which are reasonably priced for all of the work that goes into designing these clocks.
Some parts on this clock needed a 2mm bit, so I decided to use a 1.58mm diameter bit for the whole thing. I cut at 800mm / minute and 1mm depth for each pass.
800mm/min with a 1.58mm bit, that’s pretty fast. Is the bit Carbide or plain HSS. What RPM, number of flutes etc…
When you say new cambam did you mean new to you or a new version? Love cambam but last new version was years ago I think…
Those are some nice cuts there.
Henrik, 800mm/min doesn’t seem so fast when it does 7 passes to cut the part. I typically don’t cut faster than about 1300mm/min with a 1/8" bit. The chips that are generated are micro-fine saw dust, so I actually need to turn down my RPM a little to get the right feed rate for maximum bit life. I don’t know what RPM it is running at. It is a 24V 400W motor running at 3/4 throttle. The bits are 2 flute carbide that I got from Ebay for about $2 each.
Brad, CamBam is new to me. I downloaded their latest a month ago and that is what I am using now. I was using BobCad since 2003 and it never seemed like things were harmonious until I started using CamBam. Right now I design in eMachineShop->DXF->CamBam->GCode->LinuxCNC.
Thanks @Daniel_Jones
I’m going to cut a lot of thin plywood in the near future and have natural interest in your parameters for this reason. If it’s OK with you, I would like to know more from your experience.
Just out of curiosity and interest, I have been looking up the parameters for your job, and with the parameters I have now, but guessing the remaining tool sizes and just using Modelling board (under plastics), i get a feed of approx. 335 on optimal conditions and 20000 RPM. Setting feed to 240% is 800 mm/min, still within tool safety.
The interesting thing is that even at 300% feed, the torgue is still near 0 Newton, which is good.
You could try calculate yourself using http://zero-divide.net/?page=fswizard
Experimenting with the values, shows that you should be able to cut at full depth but slower, but still overall faster than current job conditions. But thats up to you to try. If you do try, please let me know how it turns out. It’s also important how the cut item finish is.
Btw. It should be possible for you to construct a RPM meter using an arduino with some lightsensitive sensor. I did that myself as I had the same problem with not knowing the spindle speed. I think I once made an entry on my G+ on that topic.
Good work though on your clock.
I also tried CamBam, and liked it’s versatility, until it crashed on me. I also feel that CamBam is difficult to use, having an older UI.
I’ve tried an older version of Aspire, which is also an excellent CAD CAM 2.5D package.
Is the clock ticking 
Hi Henrik,
The clock is still at the same point as what I posted in the picture. It seems I spend too much time at my day job.
With a small bit like this one, I prefer not to load it too much for fear of breaking it. Cutting the 7mm depth in one pass is tempting, but I prefer to take it more conservatively. The problem I had in the past with moving slower during a cut is that the wood tends to warm up and discolor due to the friction. Cutting wood is not as predictable as plastic. With ABS all the chips are identical to each other and the bits seem to go through it like butter. With wood there is different densities and if I load the tool too much, it could bounce around. Having a super accurate machine should keep that from happening but for most of us that is unrealistic. That is why I prefer to move fast and keep the load down by doing shallow passes (1mm). So far I have had good luck with not having very much of the top layer of ply lift up. There are a couple places where some gear teeth lost a little on the edge, but overall I am pleased with the results.
I went ahead and ordered a $15 ebay tachometer. I can’t fathom starting yet another project just to read the speed.
Excellent @Daniel_Jones . I agree on the density of wood, and if the wood discolors due to heat, then something is wrong with the feed and speed.
Great getting the tachometer. I think you will get a better view on the CNC job conditions in the long run.
I have a little Max NC10 where the spindle is controlled from mach3 with PWM, but the speed was reduced when the spindle (1/10HP) was even slightly loaded. So i built a arduino to give feedback on the actual sped to mach3. Now Mach3 tries to keep the spindle speed, as long as the load is not to high.
When the tach gets here I will post the results of a test with different feed rates. I would like to finish cutting the clock parts this weekend. After that, it may be worth sacrificing a bit in the name of science determining the physical speed limits. Are you going to cut ply or solid hardwood on your next project?
I’ll be cutting plywood in 6.3mm mostly, but other thicknesses also depending on project.
Good luck with everything CNC, I’ll be looking forward to read more from you…