chipping (tear out)

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tptbum
Posts: 29
Joined: Sat Jun 09, 2007 9:17 am
Location: Ann Arbor, MI area

chipping (tear out)

Post by tptbum »

Hi all,


I am trying to route the WRC that I stripped about three years ago (long story) I made some dummy strips out of a scrap 2 x 4 to test my set-up and they worked perfectly, then I tried the real strips and it was a minor disaster! lots of chipping.

I tried to read some archive threads that might be helpful and caught some reference to "climb cutting" but don't know what that means.

could it be that my strips are brittle after three years in the garage? Or am I doing something wrong?

Thanks,

John
Ann Arbor
AlanWS
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Joined: Thu Mar 17, 2005 4:30 pm
Location: Shorewood, WI

Post by AlanWS »

Climb cutting means running the stock past the router in what is usually considered the wrong direction, so the cutter pushes the stock in the same direction you are moving it, rather than opposing that motion. It is usually considered quite dangerous, particularly on a router table because the stock can be thrown and your hands might be pulled into the cutter. With very long strips and adequate restriction of the stock, it is said to be safe by some, but I've not tried it. In any case you need to know exactly what you are doing.

But it is very resistant to tearout because the cutter cuts on its way into the work rather than on the way out, as in usual routing. But that also means it can push the stock away from the fence, if that's not well controlled.

I think John Michne's webpage (michneboat.com ) hs some discussion of this procedure. Look here: http://michneboat.com/Making%20Strips.htm

I don't know if the age of the strips is a factor.
Alan
firefightered
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Location: NW Alabama

Post by firefightered »

I agree with Alan. Just make sure you use feather boards to hold you strips in place. this will help with kick-back and keep you strips uniform. Another thing that works is zero clearance under your strips. This keeps your stock from flexing. And sharp cutter blades is a must.
Herby
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Larry in Champaign
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Post by Larry in Champaign »

If you are not using a climbing cut, make sure you are cutting with the grain. I have not had a problem routing, but I do make certain I'm running with the grain when planing or I'll get tearout. As Herby pointed out, any movement (vertical or side to side) can cuase the grain to catch. I have to push/pull my strips through the multiple featherbords controlling the strips when routing the bead and cove.

Larry
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Davesbuild
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Post by Davesbuild »

Hi John,

I did have the same problem as you have stated. I tries several methods to resolve it, but wasn't successful.

I ended up turning up the speed on my router and reversing the direction of the cut. (routed the strips with a "climbing cut).

After doing this, I would suggest the following:
-wear good leather gloves and hang onto the strips tight!
-place a sheet of plywood or something else in-front of the router table in case one gets away from you (I had this happen a few times and the strip went shooting down my driveway - make sure the dogs and kids are well away from this area)
-when you get close to the table, work from the side and ALWAYS keep one hand on the strip. This means pulling the last foot or so of strip through the router.
-use a relatively fast speed on the router and feed slowly.
-use feather boards to hold the strips firmly against the fence and the surface of the router table.

Good Luck,'
Davesbuild
tptbum
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Joined: Sat Jun 09, 2007 9:17 am
Location: Ann Arbor, MI area

Post by tptbum »

Given all the caveats I have read regarding climb cutting I think I will try some of your other suggestions first.

I was using only one feather board (before the bit) perhaps I will make a couple new feather boards and put one after the bit and one on the fence to hold the strip down.

Let me just mention a few more details and see if it changes any of your advice:

I don't have much experience woodworking - this isn't my first project, but I've never done anything this ambitious before! Also, I've never worked with cedar before.

My friend, who has much more woodworking experience than I, but has never built a canoe or worked with cedar, said that my strips are pretty dry and brittle and I should lay them all in the driveway and pour water on them and let them soak it up overnight.

Both my router and my router table are pretty cheap, I cannot adjust the speed of the bit on the router, but I have managed to build 8 foot infeed and outfeed tables and attach them pretty well to my table and the table seems fine to me. I tried to borrow a better router and router table, but the router bit that I bought is one of those with the cove cutting bit on the bottom and the bead cutting bit on the top and it wont fit through the hole in my friend's table, but it fit's through my sears router table.

Thanks for all the advice, I think today I will make a few more feather boards and give that a go.

John
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Denis
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Joined: Tue May 11, 2004 8:11 am
Location: Lakefield, Ontario

chipping

Post by Denis »

I would suggest it is likely the direction of the grain in your strips that is causing the chipping. I often have to reverse a strip to cove it if i see the grain runs out the wrong way.

Age of strips I find very unlikely as I have worked with cedar strips 30 plus years old that were stacked in a barn and had little difficulty doing the bead and cove as long as I watched the grain on the strip and fed it carefully into the router bit.

The following link may be of some help or interest to you

http://www.bearmountainboats.com/phpbb2 ... sc&start=0

This pic may also be of some help

Image

Denis
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Jim Dodd
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Post by Jim Dodd »

Nice set up Denis !

The only thing I do different, is I run my strips "Between" the bit and the fence.

If I want, say 3/4" strips, and my planks vary from 3/4" to 1", my setup will insure that all strips, from end to end are 3/4".

Now for John, are your strips quartersawn ? The planks you start with should be "Slash cut", that means when you look at the end grain, it should run from left to right, not up and down.

Your strips could very well be brittle ! I have always cut, and beaded and coved, the same day I would'nt pour water on my strips. Maybe put them in a room with a humidifier for a few days.

Good luck !

Jim
Keep your paddle wet and your seat dry!
tptbum
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Joined: Sat Jun 09, 2007 9:17 am
Location: Ann Arbor, MI area

Post by tptbum »

I have to admit some confusion about grain.

I know that I paid attention to grain when I picked out the planks three years ago, I did my best to pick out whatever kind of grain the books suggested, I will re-read everything I can find about grain and check my strips.

As for cutting against the grain or with the grain, If the bead cut is with the grain would the cove cut not be against?

john
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Larry in Champaign
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Post by Larry in Champaign »

You can turn the strip over to run with the grain.

Don't be afraid of the climbing cut, just use multiple holddowns to secure the strip. If the strips slide through your setup the holdowns are not tight enough. If they are tight enough you have to push/pull the strips through and then they won't get away from you.

Image
tptbum
Posts: 29
Joined: Sat Jun 09, 2007 9:17 am
Location: Ann Arbor, MI area

Post by tptbum »

Wow Larry,

I am impressed,
Four feather boards vertical and four horizontal.
I guess I am under restrained!

OK, so tomorrow I make some more feather boards and maybe improve my router table set up - I bet I can make a fence better than the plastic one that came with the table.

Thanks for all the advice guys,

I'll let you know how things go.

john
tptbum
Posts: 29
Joined: Sat Jun 09, 2007 9:17 am
Location: Ann Arbor, MI area

quick update

Post by tptbum »

Hi all,

Thanks again for all the suggestions,

I spent a solid day making a new fence and feather boards for my crappy little router table. I considered shelling out some dollars for a nice router table, but I managed to get something that works pretty well with what I built.

Then, after some trial and error (':sad') I finally figured out what Dennis was saying about routing with the grain! After I figured it out I still read the grain wrong a couple of times. Also, I had glued some of my strips together with opposing grains. Oh well, a busted strip or two is a good lesson learned, and I already have some ideas of what to use the "waste" strips for.

Today I need to replace the strips that didn't make the cut (so to speak) I am going back to the lumber yard for some more cedar and starting the process over again. I think I only need two or three more strips to do my project - I think I'll make 15.

Good news is only one of my scarf joints didn't survive the process (so far).

John
James Hanrahan
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Joined: Thu Sep 13, 2007 6:48 pm
Location: Wiarton Ontario

Post by James Hanrahan »

Hi John,
Maybe a little late now, but see the One Ocean Kayak site for a neat setup to rout B&C on your strips. It,s a simple jig and works great as I can attest to it.
Good luck
James
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