# Using a pattern bit?



## tvman44 (Jun 25, 2013)

Tried using a pattern bit for the first time today and the results were horrible. Do you trim the wood so it is close in size to the pattern or just cut away with the pattern bit? I 1st tried to cut away with the pattern bit but ended up splitting the wood. Then tried trimming the wood on the band saw close to the shape desired and that was better but still not good. How do you guys do it?
Bob


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## oughtsix (Feb 13, 2015)

What kind of wood are you using? Some woods are worse for splintering than others.

What does your pattern profile look like? If the pattern is profiled so you have to cut against the grain that makes it difficult to control splintering.

Is the bit a new sharp bit or an older bit?

Pre-cutting the pattern on a band saw generally makes the routing go easier and faster with less splintering.


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## tvman44 (Jun 25, 2013)

It is a brand new bit 1st time used, 1st piece of wood was Western Red Cedar, 2nd was Red Oak.







This is what I was trying to make. I ended up cutting this on my scrollsaw.


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## Stick486 (Jan 4, 2013)

splitting the wood ya say...

look to a dull bit or too fast of a feed rate....
or both...
single flute... not so good...
two flutes.. they aren't cutting equally...

note:...
economy bits are known to have all of these issues right out of the package...


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## Quillman (Aug 16, 2010)

Time to switch from carpet tape to clamps, stops and crowders.
Moreover, if the work is breaking, it's time to switch to collars.
With collars the stress/pass can be so low that that there are no substantial forces trying to rip the work apart. E.g. dividing the work thickness into ten equal thickness passes renders very little tearout and rarely a busted part. If the cutter pathway is tortuous (cutting back on itself, e.g.), it may be the only way to rout it (in stages).


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## Cherryville Chuck (Sep 28, 2010)

Western red cedar is the worst wood I know of for splitting grain. I work with it lots because it's one of our native woods here and plentiful. Saw close to the line, try what Quillman suggested, and maybe try reversing feed direction (climb cut). If you are only nibbling away at it and not taking much wood off you may be able to get away it.


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## oughtsix (Feb 13, 2015)

I can see how that pattern would be problematic for splintering. Oak also has a tendancy to splinter.

My best guess would be to try a spiral cutting bit instead of a straight flute bit to get more of a shearing action. I have never tried a spiral flush trim bit so I am just guessing that one might help.

How many pieces do you have to cut?


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## tvman44 (Jun 25, 2013)

Ok, I was using a bearing guided 2 flute pattern bit, but started wondering before getting on here this morning if using a guide bushing and a straight or spiral bit would be easier. I have a couple of straight bits I can try but could get a spiral bit if I decide to try that. What would be better, a straight bit or a up cut or down cut spiral bit for hand held router?
I want to make about a dozen of these for now, may may more later, either way it is time to learn to use a pattern now. I ended up cutting the desired piece on the scroll saw and sanding the edges, but think a pattern ,might be easier and faster.
Bob


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## Quillman (Aug 16, 2010)

Cutter design doesn't matter much for the short run, sharpness counts, however. And the largest safest, most practical (can get into the tighest radius) should be selected. Moreover, it should be as short fluted as the work is thick. Long cutters are risky, deflect and chatter the work.


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## GregLittleWoodworks (Dec 9, 2014)

Bob, I do a lot of pattern routing and have tried many different pattern bits. The spiral compression bit made by Whiteside has produced the best results by far. Before getting this bit I had the same problems you mention but this bit has solved most all of them. I also like the upper/lower bearing feature because I can flip the pattern and piece over and rout from either top or bottom...and this helps a lot based on grain direction and wood type.


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## tvman44 (Jun 25, 2013)

#1 Do you have to trim close to the line before using this bit?
#2 Is that a up cut or down cut?



GregLittleWoodworks said:


> Bob, I do a lot of pattern routing and have tried many different pattern bits. The spiral compression bit made by Whiteside has produced the best results by far. Before getting this bit I had the same problems you mention but this bit has solved most all of them. I also like the upper/lower bearing feature because I can flip the pattern and piece over and rout from either top or bottom...and this helps a lot based on grain direction and wood type.


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## oughtsix (Feb 13, 2015)

tvman44 said:


> #2 Is that a up cut or down cut?



I am not sure but it looks like that Whiteside bit is both up cut and down cut. Looks intriguing! It looks like it will shear towards the center of the stock on both the upper and lower sides of the stock to minimize splintering. Pretty cool!


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## tvman44 (Jun 25, 2013)

Yes it looks nice, but the price tag is a little to rich for me. $130.00 for 1 router bit?


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## oughtsix (Feb 13, 2015)

$130... Ouch!!!


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## Phil P (Jul 25, 2010)

tvman44 said:


> #1 Do you have to trim close to the line before using this bit?
> #2 Is that a up cut or down cut?


Hi Bob

You have to trim close to the line before using ANY trimmer bit, not just this one. That bit is what we call a compression bit - bits like that are designed to minimise the surface spelching you get with _veneer faced boards_ on the top surface (with an upcut only spiral) or on the bottom surface (with a downcut only spiral) or on. It can't and won't cure splintering caused by short/opposed grain although it _might_ reduce it somewhat. There are only two ways to tackle this - read the grain and climb cut (in progressively deeper stages) in the affected areas or make the edge trim cuts in multiple passes as mentioned by others and also consider moving to a guide bush/cutter set-up. The only other thing I can say is that cutter sharpness is also a factor

Regards

Phil


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## GregLittleWoodworks (Dec 9, 2014)

tvman44 said:


> #1 Do you have to trim close to the line before using this bit?
> #2 Is that a up cut or down cut?


It is important to trim as close as possible to the line. I always try to get at least 1/16" max. The bit is a compression bit and is a combination of an up-cut and down-cut bit. Yeah, it's expensive and I had to think about it for a while before buying it...but I am glad I did and I would buy it again.


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## tvman44 (Jun 25, 2013)

That is what I needed to know. If I need to trim, I think I will just do like I ended up doing on my first one, cut it on the scroll saw and sand and be done with it.


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