I'm building an English garden bench out of redwood. To cut the
curved pieces (legs and arms) I do the following:

1. created clean templates of curved pieces out of 1/4" tempered
hardboard,
2. traced the pattern outline on the piece,
3. rough cut to within 1/8" of the outline using a jigsaw (do not own a
BS)
4. attach template using double face tape to top of rough cut piece.
5. Use 2" flush trim bit (top pilot) on router table to trim to
pattern.

The problem I am having is that when I do the flush trimming, it trims
95% of the time OK but occasionally, I get chipout and chunks are taken
out of the piece along the edge I am routing flush to the template.

The lumber is kiln dried clear all heart (CAH) redwood that is
dimensioned lumber (1 1/2" thick). It is beautiful wood (but
expensive), very soft, and seems very dry and splinters easily.

I take the trimming operation very slowly but still get the problem.
The bit is a 1/2" shank, dual flute, 2" flush trim bit Rockler house
brand. I've even tried climb cutting but the operation is very
difficult.

Either it is my technique or just a result of this wood species.
Maybe kiln dried redwood heartwood is just too frail for this type of
operation. The plans called for using a bandsaw to cut to shape --
using the pattern and flush trim bit is my idea.

Any suggestions?

Jerry, is there anything about the design that necessitates
pattern-routed precision? Could you just cut to the line, sand the
edges smooth, and call it done? Sounds like the routing is more trouble
that it's worth.

You could also use the RoboSander - a bearing guided sanding drum.
Woodcraft sells them.

That is one of the problems with curved pieces. One one side of the
curve the cutter is cutting into the grain. On the back side of the
curve it's opposite. Several ways to do it. Look at the grain, when you
get to an area where the cutter will lift the grain. Hold the work firm
and take small cuts like your nibbling away the wood. Once the bulk is
gone then make one final pass. You could also do a climb cut but it's
not recommended. The best way is to look at the grain. Then mark your
template where the cutter will lift the grain. Use a flush trim bit on
all the curves with the cutter cutting into the grain. With them done
chuck up a pattern bit with the barring on the bottom flip the work and
finish the cuts. With the work flipped and a pattern bit the cutters
will be cutting into the grain.

..
Jerry wrote:
I'm building an English garden bench out of redwood. To cut the
curved pieces (legs and arms) I do the following:

1. created clean templates of curved pieces out of 1/4" tempered
hardboard,
2. traced the pattern outline on the piece,
3. rough cut to within 1/8" of the outline using a jigsaw (do not own a
BS)
4. attach template using double face tape to top of rough cut piece.
5. Use 2" flush trim bit (top pilot) on router table to trim to
pattern.

The problem I am having is that when I do the flush trimming, it trims
95% of the time OK but occasionally, I get chipout and chunks are taken
out of the piece along the edge I am routing flush to the template.

The lumber is kiln dried clear all heart (CAH) redwood that is
dimensioned lumber (1 1/2" thick). It is beautiful wood (but
expensive), very soft, and seems very dry and splinters easily.

I take the trimming operation very slowly but still get the problem.
The bit is a 1/2" shank, dual flute, 2" flush trim bit Rockler house
brand. I've even tried climb cutting but the operation is very
difficult.

Either it is my technique or just a result of this wood species.
Maybe kiln dried redwood heartwood is just too frail for this type of
operation. The plans called for using a bandsaw to cut to shape --
using the pattern and flush trim bit is my idea.

Any suggestions?

Jerry wrote:

I'm building an English garden bench out of redwood. To cut the
curved pieces (legs and arms) I do the following:

1. created clean templates of curved pieces out of 1/4" tempered
hardboard,
2. traced the pattern outline on the piece,
3. rough cut to within 1/8" of the outline using a jigsaw (do not
own a BS)
4. attach template using double face tape to top of rough cut
piece. 5. Use 2" flush trim bit (top pilot) on router table to
trim to pattern.

The problem I am having is that when I do the flush trimming, it
trims 95% of the time OK but occasionally, I get chipout and
chunks are taken out of the piece along the edge I am routing
flush to the template.

The lumber is kiln dried clear all heart (CAH) redwood that is
dimensioned lumber (1 1/2" thick). It is beautiful wood (but
expensive), very soft, and seems very dry and splinters easily.

I take the trimming operation very slowly but still get the
problem. The bit is a 1/2" shank, dual flute, 2" flush trim bit
Rockler house brand. I've even tried climb cutting but the
operation is very difficult.

Either it is my technique or just a result of this wood species.
Maybe kiln dried redwood heartwood is just too frail for this type
of operation. The plans called for using a bandsaw to cut to
shape -- using the pattern and flush trim bit is my idea.

Any suggestions?



I do a lot of pattern routing, but not with the setup you describe.
I've never had much luck with it. I use a 1/2" bit with a bushing in a
router table...
____
| | _______________
1/2" straight bit - | ||
| || - wood
|____||_______________
________bushing----__| ||______________- pattern

I don't rough trim with a bandsaw... I cut entirely with the router.

First difficulty is cutting the entire 3/4" thickness. It works best
if I cut 3/16" or so and then raise the bit incrementally. The end
result is pretty good.

Second difficulty is that the finished piece is approx 1/16" larger
than the pattern. I take that into account when I make the pattern so
it's not a problem.

Based on my experience, to address your particular difficulty, I would
first suggest that your biggest problem is trying to trim 1/8" of wood
in one pass. It may not seem like much, but it would seem to be
causing problems. The wood is not getting cut cleanly. A sharp bit
spinning effortlessly through the wood makes a nice clean cut with
minimal tearing.

Because you are using a bit with a bearing, you don't have the option
to incrementally raise the bit as I do so another solution must be
found.

The most obvious solution is to trim a little closer with the bandsaw
so that the bit doesn't have to work as hard.

Another possible solution (in conjunction with the suggestion above)
is to use a 1/2" spiral bit. I believe someone makes one with a
bearing. Exactly what you're using now, but a with a spiral cutter.

Hopefully you'll find some use in my comments.

Joe Barta

Or buy one of these
http://www.leevalley.com/wood/page.aspx?c=2&p=51851&cat=1,46168,46171&ap=1

"Jerry" wrote in message
oups.com...
I'm building an English garden bench out of redwood. To cut the
curved pieces (legs and arms) I do the following:

1. created clean templates of curved pieces out of 1/4" tempered
hardboard,
2. traced the pattern outline on the piece,
3. rough cut to within 1/8" of the outline using a jigsaw (do not own a
BS)
4. attach template using double face tape to top of rough cut piece.
5. Use 2" flush trim bit (top pilot) on router table to trim to
pattern.

The problem I am having is that when I do the flush trimming, it trims
95% of the time OK but occasionally, I get chipout and chunks are taken
out of the piece along the edge I am routing flush to the template.

The lumber is kiln dried clear all heart (CAH) redwood that is
dimensioned lumber (1 1/2" thick). It is beautiful wood (but
expensive), very soft, and seems very dry and splinters easily.

I take the trimming operation very slowly but still get the problem.
The bit is a 1/2" shank, dual flute, 2" flush trim bit Rockler house
brand. I've even tried climb cutting but the operation is very
difficult.

Either it is my technique or just a result of this wood species.
Maybe kiln dried redwood heartwood is just too frail for this type of
operation. The plans called for using a bandsaw to cut to shape --
using the pattern and flush trim bit is my idea.

Any suggestions?

http://www.woodcraft.com/family.aspx?familyid=8016

Works great for me.
Dave





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Thanks for all of your replies. I see my problem as trying to cut into
the grain with a wood that is already prone to chip-out.

Excellent ideas. Flipping the pattern to the other side to continue to
cut with the grain is probably the easiest. I like the robosander on
my DP idea. With 50 grit on redwood, it would cut like a router bit.

Whiteside as a spiral flush cut bit but at $70, an expensive solution
and would probably still cause tearout unless a backer board was used.


Thanks again for your suggestions.

"Jerry" wrote in message
ups.com...
Thanks for all of your replies. I see my problem as trying to cut into
the grain with a wood that is already prone to chip-out.

Excellent ideas. Flipping the pattern to the other side to continue to
cut with the grain is probably the easiest. I like the robosander on
my DP idea. With 50 grit on redwood, it would cut like a router bit.

Whiteside as a spiral flush cut bit but at $70, an expensive solution
and would probably still cause tearout unless a backer board was used.


Consider also simply back cutting in the areas that the grain is prone to
chip out. This is standard procedure when routing end grain on drawer
fronts.

I am not the original poster, but I thank you for the link.
That is a fantastic idea.

Frank

wrote in message
oups.com...
Or buy one of these
http://www.leevalley.com/wood/page.aspx?c=2&p=51851&cat=1,46168,46171&ap=1

wrote in message
oups.com...
Or buy one of these
http://www.leevalley.com/wood/page.aspx?c=2&p=51851&cat=1,46168,46171&ap=1

Even better is to use a shaper. Reverse the motor and the cutter.

Toller wrote:
wrote in message
oups.com...
Or buy one of these
http://www.leevalley.com/wood/page.aspx?c=2&p=51851&cat=1,46168,46171&ap=1
Even better is to use a shaper. Reverse the motor and the cutter.


I am not a shaper user and am curious why this is better. This bit I
linked, own and use a lot couldn't be simpler to use just raise and
lower with my router lift.

I do this a lot. You generally go around the piece counterclockwise. When I
get to a place where the grain is ending, such as at a curve, I feed
backwards in small bites. When it is very close to flush I feed the proper
direction. I think feeding back wards is called climb cutting. The blade has
to be very sharp to cut end grain and you have to have a very steady hand
and take small bites.
max

I'm building an English garden bench out of redwood. To cut the
curved pieces (legs and arms) I do the following:

1. created clean templates of curved pieces out of 1/4" tempered
hardboard,
2. traced the pattern outline on the piece,
3. rough cut to within 1/8" of the outline using a jigsaw (do not own a
BS)
4. attach template using double face tape to top of rough cut piece.
5. Use 2" flush trim bit (top pilot) on router table to trim to
pattern.

The problem I am having is that when I do the flush trimming, it trims
95% of the time OK but occasionally, I get chipout and chunks are taken
out of the piece along the edge I am routing flush to the template.

The lumber is kiln dried clear all heart (CAH) redwood that is
dimensioned lumber (1 1/2" thick). It is beautiful wood (but
expensive), very soft, and seems very dry and splinters easily.

I take the trimming operation very slowly but still get the problem.
The bit is a 1/2" shank, dual flute, 2" flush trim bit Rockler house
brand. I've even tried climb cutting but the operation is very
difficult.

Either it is my technique or just a result of this wood species.
Maybe kiln dried redwood heartwood is just too frail for this type of
operation. The plans called for using a bandsaw to cut to shape --
using the pattern and flush trim bit is my idea.

Any suggestions?