I am new to CNC and have been working for a few weeks to tune everything. I have a pro 4896. So far I have gone through one spoilboard trying to get things right. At this point, I am wondering if I have it as good as it can get.
This has been a real learning experience. I ran through the leveling and surfacing routine several times. Then I tried to flatten the spoilboard,3 times with attempting adjustments. I am using an amana 2+2 insert bit that is 1.5in wide. For testing the cut i am using a 90% stepover. But, I keep seeing tool markings. I even used a tramming indicator with a piece of glass and attempted doing the whole level the glass and test and redo. But, my glass isn't flat. So, i can't trust anything because I have no reference that I know is actually flat. Thought about getting a reference granite plate. But want to ask you people before doing anything else.
I can take pictures later of needed. The tool markings left are noticeable, but I think this is inevitable with any machining. I would always see the lines, right? Is it possible to get a surface flat with the bit without seeing any tool marks? I have looked online at so many videos and pictures. And I swear they look perfect.I know I'm using a big bit too. I will decrease my stepover in the final pass.
But what is the reasonable way it should look after surfacing? Should i always see the tooling lines and sighs the stepover have a fuzzy strip?
Any help on this would be greatly appreciated. I'm going nuts.
You are always going to see tool marks even with perfect tram. If you can feel pronounced ''ridges'' then you are probably out of tram. If you are getting light fuzz, try a light buff with a ScotchBrite pad. Maybe a different tool bit would help.
Here is how I tram my router. That is a welding rod with a 1/2 inch slug brazed to one end to fit in the collet. I use a piece of paper as a feeler gauge, most paper is about 0.003 thick. If it's within 0.003 in 30 inches, then that is close enough for a router (or my mill for that matter). You'll go nuts ''chasing zeros''. Just swing the stylus around and check at 4 quadrants. No, the stupid marks in the table are not mine, I bought the machine used.
Here is a picture of facing the spoil board. You can see the tool marks, but you can't feel ridges. Using 1 1/4 inch flat cutter with 70% stepover, about 0.015 DOC.
Thank you for the details. I feel much better about this now. I will make one of those for future use also. I'll try 70% step over as well. It is true, i keep chasing zeros.
Yep, I agree that you will always see the tool marks. I see them in mine but I can't feel or measure them. I use a dial indicator to tram cause I have one. You can REALLY drive yourself nuts with one of those! Heck, breathing on the darn thing makes it move! Ha! I did get mine within a few thousandths after some fiddling. It wasn't really that bad. I performed the measurement in the area where I cut the most. I have a Standard 2448, but most things I do fit within a square foot or so. I used a piece of glass I had laying around too. Old scanner beds are a nice source. I bought a better dial indicator (tenths), but I haven't worked up the nerve to mess with it. So far, "a few thou" has been fine for what I do.
Oh, I didn't have to remove but about 0.030" or so of material to get it flat. How much are you removing that you have gone through a board already?!? Also, I flattened the spoil board, but I use a sacrificial board on top of that. I screw it down (it is much smaller), then flatten it. I have to clean it up once in a while and it is starting to look like swiss cheese, so I'll replace it soon.
I first took .15 off, but i didn't have the offsets set correctly and took off far too much. Then i got offsets figured out and took the original .15. but before that all happened i drilled the bolt pattern and at the second to last row the Ethernet smooth stepper had one of those errors that loses position and tells you or probably didn't. I listens to the error and pressed go again and the bit buried itself and did an arc. Luckily I was able to stop it before it ran in to the supports.
I will try a .03 cut along with the other recommended stuff. I am using the file from cncrp for the spoilboard. Modified a bit. But with the bit size, i think I'm going to have to run it like Jim Dawson. The bit is too big to pass the edge enough to clear the whole path. I end up with half Moon shapes. Then pass around the edge at the end. I don't like it. Should have enough on the front and back to do the full pass without issue.
How flat should my spoilboatd be?
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