Router Bit Tear Out

[Ron Dudelston]

Folks, I’ve made and sold a ton of cutting boards and cheese slicers over the years but I’ve hit a snag.  I’m building stock for the 2026 Christmas sales and I decided to mix up my inventory of cutting boards  by buying some acrylic templates and make some with fancy smancy handles.  I’m having mixed results because of router bit grab and tearout particularly on the inside of the handles and it has to be the bit selection.  I’ve used 2 fluted flush trim bits, spiral up feed flush trim and even compression flush trim bits.  I’m ready to buy a new Whiteside 2 fluted 1/2” diameter, 1/2” shank but I thought I would reach and ask for your input.

 

 

[Fred W. Hargis Jr]

Maybe instead of the bit, it's that particular plastic??? Maybe a different kind would work better and still meet the requirements you have? just kind of thinking out loud. That said, I think the 2 flute would be better, but one with a shear cut instead of the straight up/down flutes (if that's what you tried).

[lew]

Don't shoot the messenger, but I guess you have trimmed away the waste on the inside of the handle hole and around the the perimeter. 

 

 

[PeteM]

I was doing curved surfaces some years back and noticed that tearout and even wood disintegration would occur.  I think it's the change of grain direction that throws me.  I found that very light cuts were necessary, and in particular a final "clean up" shave helped.

[Ron Dudelston]

Fred, I used 3 o 4 different styles of bits with marginal results.  The plastic template is 1/4” think and I nail it down with double backed carpet tape.   Lew and Pete have carnal knowledge of the process because you have to trim the openings back really close to the template line and take baby cuts.  Cutting with the grain is fine but the end grain makes your sphincter pucker.

[Fred W. Hargis Jr]

What about climb cutting???

[HandyDan]

Routers are my most hated tools.  I never could get a satisfactory finish either. I feel for you.  

[Danl]

My Opinion:  Use a 1-1/2" dia. compression bit with bearings on both ends.   Use double sided tape to adhere the template to the wood.  Read the grain direction and use both ends of the router bit (top & bottom).

The larger dia bit should result in a smoother finish and having two bearings will allow you to flip the board so that you are always cutting down hill.  

Infinity tools sells a bit(s).

Danl

[Danl]

18 minutes ago, Danl said:

My Opinion:  Use a 1-1/2" dia. compression bit with bearings on both ends.   Use double sided tape to adhere the template to the wood.  Read the grain direction and use both ends of the router bit (top & bottom).

The larger dia bit should result in a smoother finish and having two bearings will allow you to flip the board so that you are always cutting down hill.  

Infinity tools sells a bit(s).

Danl

Oops, I see the 1-1/2" dia is too large for the handle hole.  Suggest using the 3/4" dia bit for the handle hole.

Edited June 11 by Danl

[Ron Dudelston]

I thought about bumping up to 3/4.  That would increase the surface speed.

[Danl]

Good set-up does not remove the pucker factor.  Danl

[lew]

Picture of the problem??

[Wichman3]

I'm primarily a scrollsawer, so you know where my mind went first.   But, how are you roughing out the interior cut? Is that method tearing the grain of the wood so that when you go to finish the cut, the wood is already torn?

[Ron Dudelston]

4 hours ago, lew said:

Picture of the problem??

I wish I could.  Luckily, the boards were large and I could salvage them and the evidence is in the burn barrel.

[Ron Dudelston]

3 hours ago, Wichman3 said:

I'm primarily a scrollsawer, so you know where my mind went first.   But, how are you roughing out the interior cut? Is that method tearing the grain of the wood so that when you go to finish the cut, the wood is already torn?

Actually, I am cutting them out with a scroll saw.

[HandyDan]

I would then use oscillating spindle sander to finish them and cut sharp edges with sandpaper.

[Wichman3]

7 hours ago, Ron Dudelston said:

Actually, I am cutting them out with a scroll saw.

So... next question about the SS blades. Flat or spiral? Size and type?

[Fred W. Hargis Jr]

Did you decide to not get the 3/4" bit?

[Ron Dudelston]

55 minutes ago, Fred W. Hargis Jr said:

Did you decide to not get the 3/4" bit?

I have ordered the bit, Fred.  I think the key is to minimize the stock removal.  That is, trim close to the line. 

[Ron Dudelston]

5 hours ago, Wichman3 said:

So... next question about the SS blades. Flat or spiral? Size and type?

I will use a flat, very fine.