So I cut this out tonight, thickest wood I’ve done so far (only done 1/4" or thinner until this 1" piece) but on the final cutout the machine shut off and disconnected (literally at 99.8%) but it was easy enough to finish it with my Dremel and some sanding. I think the 1/4" bit was rubbing the walls inside the outside cutout. So, the question is, what is the proper fix so this does not happen in the future?
My thoughts are either a bit with longer flues (mine was only 3/4" while the cut depth was just a hair over 1") or somehow make it cut wider (pocket) so there it does not get pinched between the 2 walls??
In other words I believe it over powered the spindle motor due to friction though it did not sound bad or anything and did not burn the wood. And I was keeping it vacuumed out well so the fact I ran out of flute is my (NOOB) best guess. Oh, and the settings were all the default for the bit that CC decided to use.
I still don’t know how to calculate best settings so maybe someone can give me a clue (or just tell me what to change to what).
These were both hardwoods and the dark one is walnut but I don’t actually know the other one but it’s a quite a bit softer than the walnut.
Only other mistake I made was the gap between the lid inside lip. Gave a little to much so the lid wiggles. I want to make and sell these so I need to get educated on proper cutting for this stuff (the lid I can figure out) but the settings for cutting I need help with.
BTW I found a DIY food safe oil/beeswax recipe I really love for food contact wood. If anybody wants it let me know.
Oh, and yes I know the grain in the lid is going the wrong way but I used a scrap I had and it was just slightly larger than the lid so I had no choice.
Hey! My first impression was “he’s running the grain the wrong way”. Then I thought about it. If structural integrity was an issue, indeed you should run the grain long-ways. But the thickenss and size of your piece suggests this is not so. So run it however you want.
When we had wood floors installed a couple years ago, the decision was whether to run N-S or E-W. I thought of making a joke about running at 45°. Before I could crack it, the installer suggested the very same plan. We did it and are thrilled.
Looks great! I think you already answered your question - the Nomad spindle motor does not have a pile of power and spinning the (relatively large) 0.250 end mill puts it even further into the red. If you have a long deep slot, particularly towards the bottom when the walls start to deform in ever so slightly you will be using a lot of power just to overcome the friction/cutting area and probably your piece slowly pushed it over the edge into shutdown. The answer is indeed to make that slot a bit wider with some stepover such that the friction/cutting area is reduced at any one point in time. Havent used CC for quite a while but suspect pocket is indeed the way to deal with it.
And whilst I think about it cutting past the flutes tends to block the chips from exiting the flutes (particulalry in slotting) so if you are thinking about doing a large number of these an end mill with longer flutes is probably a good idea from a cut quality/tool lifetime point of view.
I think I will switch back to an 1/8" endmill (just for the outside cut) and make a pocket cut for this but I still need an 1/8" endmill with 1" flutes I guess. Any recommendations?
BTW the whole reason I got the 1/4 endmills was to use a ball endmill on the inside edge to have a radius bottom around the edge and it did work perfectly for that. And the rest of the inside was a 1/4 flat to pocket out the rest and that also went without any issues.
Or, is it OK to use the 1/4" endmill (.75" flute) if I do a pocket on the outside edge? Or will it still rub abd cause too much friction?
I still have lots to learn and am greatful for this forum and it’s members for helping me.
Thought I would post an update for anybody interested.
I thought I had the issue licked as I mad the outside cut a pocket and on the first one it finished without any issues. But the next 3 tries it failed again and again, I tried slower feeds and such to no avail and I was watching it closely one of the times when it stopped and it was moving in a straight line and just bit into the wood and stopped dead, it really didn’t seem like it was struggling, no slow downs on 90% and not even touching the walls when it happened. I could easily move the spindle motor with 1 finger where it stopped.
I came to the conclusion that the 1/4" bit was just too much for the machine period.
The only reason I used the 1/4" bits was to get a 1/4" radius at the bottom inside edge (which it did beautifully) and I just figured why not use a 1/4 flat end mill for the rest at the same time. Turns out that was a mistake.
So, for now I am switching back to my trusty 1/8" and I will do without the fancy inside radius. BTW I cut 2 with the 1/8" last night and both worked flawlessly.
The 1/4" endmills are supposed to only be used in softer materials such as Renshape.
You could use a 1/8" endmill and leave a set of steps on the inside, then make a finishing pass w/ a 1/4", or just model the whole shape and use a ball-nosed 1/8"
There are a couple of endmill sizes in-between 1/8" and 1/4" — 3/16" obviously, but also 4, 5, and 6mm — perhaps one of them would make a suitable compromise?
How many flutes are your cutters? Switching to single flutes will minimize load per revolution while still keeping chipload up.
For a 10,000 rpm machine I would think its better to have the higher sfm a 1/4 will be running. Datron makes some really nice single flute ball mills that work beautifully.
In my experience with a similar wattage spindle is that large endmills are very possible to use if load is adjusted accordingly. Adaptive load cam really helps with this. I was able to run a 6mm in aluminum so don’t give up!
