First try cutting big leaf maple....

[Doug Rasmussen]

As the title says, a first try at big leaf, western maple (or as we used to call it "firewood'). Back in the day little did we know about how valuable figured western maple would become.

Very soft, light and punky type wood needing sharp tools. The pictures show test cuts on highly figured air dried pieces using the CNC with carbide cutters. My intention is to make some elliptical shaped bowls with concave fluted exteriors.

The first cut ended up with what looked like a ball of fuzz. The wood doesn't seem to chip out, more like it just pushes fuzz rather than severing it cleanly. Discouraging results until i thought about sanding sealer. Closest thing I have on hand is a spray can of semi gloss Deft. A couple heavy coats using the heat gun to dry between coats.

The first picture shows after a cutter pass with about .01" depth of cut on the heavily
Deft saturated fuzz surface. Light surface fuzz is still there. Second picture shows the same situation after another heavy coating and and a skim pass with no additional depth setting on the cutter. The wood seems to swell a bit with each coating so the final skim of the second piece gave an acceptable surface that should buff out nicely. (I'll have to do some researching on buffing.)

My guess is, once you've used a lacquer based sanding sealer you're limited in being able to use any penetration oil type finishes. I don't know that for sure though.

Anybody hand turn BL maple? I bet it's not fun, huh?




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[john lucas]

I'm still doing tests on some metal and how sharp they get but the rule of thumb on older tools was that carbide would never get as sharp as HSS or HC steel. I know that has changed because my Hunter carbide cutters come from the factory very sharp. I winder if you can get HSS cutters for your CNC that may have a keener edge than the Carbide. Is it possible to get cutters with different edge angles that might cut wood cleaner. Very interesting piece your working on.
One other thought. Sometimes taking extremely light cuts in wood is not as efficient as slightly deeper cuts. The wood will sometimes actually cut better when you remove a little bit larger curl. I'm not talking big here just 5 or 10 thous. vs ;001".

 

[Glenn Lefley]

What type of cnc machine do you have?

 

[robo hippy]

I don't turn much of it, but when I do, it seems that I always start sanding at coarser grits than I do when turning madrone or myrtle. Just the way that stuff cuts. The tear out is far worse when the wood is a bit punky, and that can take a month or three when it is cut and on the ground. I don't think I had my 600 grit CBN wheel the last time I turned some.

robo hippy

 

[Doug Rasmussen]

What type of cnc machine do you have?

The machine this work is done on is a large metal working milling machine with a Centroid 4 axis control. The programming software is Bobcad. This is more of an industrial grade machine than the small CNC routers you see at Woodcraft and Rockler.

Everything I've shown "could" be done on the CNC routers. It's easier on my machine though with its graphical user interface. I think the sellers of the routers are missing the boat with their emphasis on routing signs. Signs are fine, but how many signs or embossed wall hangings does a person need? They are beginning to offer option rotary axis attachments more suited to solid wood workpieces than sheet goods which is a step in the right direction IMO.

The two arguments I hear most against CNC wood working are cost and the learning curve. The costs have come down so much in recent years a decent CNC setup is about the same as hand turning equipment or less. Compare the costs to a new 3502 Powermatic. Mostly I find it's the older guys who are hesitant to try CNC'ing. Young guys who grew up in the digital age "get" it real fast. The learning curve is about comparable to that of hand turning I would guess.

If anybody wants a recommendation on a CNC machine, I'd say forget the routers and buy a Tormach milling machine. The Tormach is about the closest thing to a heavy duty industrial grade machine you'll find that's well supported and versatile.at a good price.

 

[Bill Boehme]

I must be one of the "young guys". I started writing computer programs in 1967 ... fifty years ago. The company that I worked for had massive Cincinnati-Millacron milling machines that were "programmed" although the coding process was painstakingly slow and cumbersome.

 

[olaf Vogel]

The first cut ended up with what looked like a ball of fuzz. The wood doesn't seem to chip out, more like it just pushes fuzz rather than severing it cleanly. Discouraging results until i thought about sanding sealer. Closest thing I have on hand is a spray can of semi gloss Deft. A couple heavy coats using the heat gun to dry between coats.

.

Hi Doug.

My favourite solution for this is epoxy resin, thinned with alcohol.
For really soft wood like this, it soaks in pretty nicely. It also really strengthens the wood structure, since its still pretty thick.

Not sure how deep your cuts are. So you might to tin it a lot.

Of course, this rules out any staining afterwards.

Interesting work.
Do you have any pics of the machine?

Olaf

 

[JeffSmith]

I've turned a fair amount of Big Leaf maple - found it to be a joy to turn for the most part. While not as hard as harder maples, and certainly no where near as dense as madrone. it responds quite well to very sharp tools and good tool presentation. It does tend to tearout when scraped. Could it be that the milling tools are doing more scraping than shearing?

 

[Bill Boehme]

I've turned a fair amount of Big Leaf maple - found it to be a joy to turn for the most part. While not as hard as harder maples, and certainly no where near as dense as madrone. it responds quite well to very sharp tools and good tool presentation. It does tend to tearout when scraped. Could it be that the milling tools are doing more scraping than shearing?

I wonder if the high speed of the cutter might not be allowing sufficient time for the cut fibers to clear the cutting edge. If there is a wad of fibers stuck to the cutting edge, even if it is sharp, it wouldn't be able to make a clean cut.

 

[JeffSmith]

I'm having a hard time getting visually oriented from one photo to the next, but it looks like you're cutting end grain for the most part. If it's an older chunk of pre-spalted BLM, going punky on you, that's a good share of your problen. try turning some that'ts a little fresher. I wouldn't characterize BLM as particularly light or prone to getting the fuzzies - that sounds more like the cottonwood we've got around here.
Can you cut the wood cleanly with a very sharp carving knife?

 

[Bill Boehme]

I'm having a hard time getting visually oriented from one photo to the next, but it looks like you're cutting end grain for the most part...

So, I'm not the only one trying to figure out what I am looking at.

The orientation of the piece and the direction of the shadows seems visually conflicting. Sometimes I think that I see a beaded pattern and then other times it looks scalloped.

I agree that hat BLM isn't exactly a light wood. I've only turned dry BLM and haven't thought of it as being difficult to cut cleanly.

 

[olaf Vogel]

The machine this work is done on is a large metal working milling machine with a Centroid 4 axis control. The programming software is Bobcad. This is more of an industrial grade machine than the small CNC routers you see at Woodcraft and Rockler.

Doug, you mention this is on a metal mill. From the speeds I know, thats often around 1000 rpm.
While my routers are often over 20,000 rpm.

Could that be an issue?