Intro and dumb questions about Desktop Max

[jerry_stanek]

I agree if you surface in the circular method you will see if your z is plumb then if you surface back and forth either in the x or y and not get any ridges then your board is smooth but your z is still not plumb

[WaltzWorks]

Thanks for the help, everyone! I was able to get the spindle back in line.

Now I've got another problem: doing the classic pocketed letter sign, I'm finding that I have weird little raised and depressed circles in places. In some spots it looks like the 1/2" bit dug just a touch too deep and in other places it looks like it was a bit too high and the 1/4" cut around the high spot.

I made sure to zero the Z in the same X-Y location for each bit and I've got a hold down on all 4 sides of the sign. When I took the sign off, I held it to a level and it doesn't seem to be warped or cupped.

Does anyone have any other ideas for possible solutions?Circle-E.jpgCircleSpots.jpg

[steve_g]

Tom…
To me it looks like classic material movement due to stress relieving or movement due to moisture content of the board reducing deep in the board after its guts were exposed. The small amount of movement we’re talking about here wouldn’t be noticeable with a level.

Solutions…

1. You might try some double stick tape under the interior of the sign as well as your perimeter hold down.
2. Complete the project as quickly as possible before it can dry out from the newly exposed wood. If you’re cutting with a router, its down blast of hot air can dry out wood with a high MC, try to deflect it.
3. Try a more stable substrate.
4. What bit are you using? A down cut bit wouldn’t try to suck the material up…

This is where I’d start… hope it helps! Let us know!
SG

[WaltzWorks]

Thanks, Steve!

1) You're right, I'm only holding down at the perimeter.
2) I was using a 1/2" bit to try to get it done faster. I don't know how to move it faster than that :-)
3) I've got an MDF spoil board. Would I be better off holding down straight to the aluminum deck?
3) It's a 1/2" spiral up and a 1/4" spiral up. Should I use a down for both instead?

[steve_g]

Tom…
By “as quickly as possible” I was suggesting that you don’t cut one path today and another tomorrow! Sometimes on very large signs, that’s not entirely unreasonable…
My preference is to cut on MDF… it’s only a matter of time until you (me) do something brain dead and cause the bit to dive through the project into the spoilboard!
I don’t know how large your total project is, often the time you save doing a bit change is inconsequential. Personally, I hate doing a bit chance and will design around it!
I’d certainly have down cut bits in my arsenal… it might even help with the chip-out you’re having on some letters.
SG

[scottp55]

Tom,
Did you get the starter bit set? May want to try using the .25" Onsrud down for everything just once for comparison?
Then maybe buy something like the Centurion .25 and .5" FEM downcut if you like the .25"downcut results.
http://www.centuriontools.com/router...&pid=767&sat=1
Personally found best pocket surface was with less than .02" cut as a last pass and use a center cutting downcut with conventional toolpath.
Under "edit passes" look at last pass.
I see Steve has mentioned some of the same things
scott

[WaltzWorks]

Thanks, Steve. I thought you meant like I needed to speed up the process somehow :-) Most of what I'm doing are in the 9x23 to 11x28 size range. Nothing big. I'm assuming that the 1/2" bit is quite a bit faster... and I have to correct something I said earlier. My detail bit is 1/8", not 1/4".

I was a bit paranoid about removing the spoilboard, so I'm glad to hear you say that!

[WaltzWorks]

Scott,

I did get the starter kit. I just realized I said I was using 1/2" and 1/4". My smaller bit is 1/8".

I'm still too new to know what I do and don't like yet as far as bits go.

Random question: would a vacuum table help with the movement/stress relief issue at all?

[scottp55]

Try using the 1/4" down AFTER running the 1/8" super O 61-040 for less tearout(not really the best bit for good pocket finish)
For a very good pocket finish with a .125" bit , I've had very good luck with this one, but you need an 1/8" collet(you should have one anyways).
If you can get away with .5" LOC.....Says soft plastic but used with Bloodwood/Purpleheart and Teak no problem.
http://www.ebay.com/itm/1-8-1250-CAR...5RaQbYIqs2btnw

I like his 16'th downs also and do all our buttonholes with them....pretty happy with all his stuff, and Very reasonably priced and fast shipping.
I might try his engraving bit selection(enter them as VBits even though they have a .012" flat) only one I had problems with was his 30 degree "Sharp" which has a .006" flat on it which myself and a friend had tips breaking off..otherwise my go-to's for tiny stuff and fairly painless for "Oopsies"
http://www.ebay.com/itm/SET-OF-10-MI...7gJ0iPQPUDHvEg
No idea on Vac.
scott

[steve_g]

Tom…
The FEM bits that Scott has recommended are bottom cutting bits, they will generally give you a better finish in the bottom of a pocket. Regular (non FEM) bits have a swallow tail look on the end and cut on their perimeter while moving, but leave swirl marks. Typically a FEM bit wants to be ramped into its cut.
SG