Best Bit For Pattern Cutting

[Keith Starosta]

I'm finally going to start making my long-awaited Adirondack Chairs. I'm making patterns for all of the components, because I'm sure I'll be making more than just one pair. This will be my first time using a router with a pattern, and just want to get opinions on what would be the best bit to buy for this application. I know that I'm probably supposed to use a flush trim bit with a bearing, but what diameter, cut length, etc.

I'm going to be using cypress, with the largest thickness being 1.25".

Thanks!!

- Keith

[glenn bradley]

Larger diameter bits seem to yield less tearout for me. I find a 1" flush trim or pattern bit to cut cleaner than my 3/8" spiral bit. What is the tightest radius you will have to cut? Standard Adirondacks don't have many curyques so I would look for a 1" dia. by 1 1/2" cutting height, 1/2" shank if that will work.

[Keith Starosta]

You're right, Glenn...the Adirondak doens't have any tight curves at all.

I appreciate the feedback. Anyone else with any opinions? :confused:

- Keith

[Gary Keedwell]

I have made a few of them and I just jig sawed them to the line and do a little sanding. The secret is to get a great jig saw. My first great tool was my Bosch and that was 18 years ago and it still cuts great. Also a good round over bit in a router.;) Gary K.

[Jim Nardi]

Both have bottom bearing's. One's a CMT and the other is a Dinmar bit. The bigger heavier One's large and the other is fairly slim about a 1/2". Both work equally as well.

[Doug Shepard]

If you have to go through 1.25" you might have to go with a 3/4" template or go with 2 different length bits. You'll have to look at the measurements to make sure the bearing will still ride on the template at the top cuts.

[Keith Starosta]

If you have to go through 1.25" you might have to go with a 3/4" template or go with 2 different length bits. You'll have to look at the measurements to make sure the bearing will still ride on the template at the top cuts.

It might be a bit of overkill, as far as the templates are concerned, but I am planning on using 3/4" MDF. Pretty much the only reason I'm doing this is because I have a lot of it on hand, and it's sturdy enough to take a beating. The longest cutting length I've been able to find on a 3/4" diameter flush trim bit it 2". I think this might do the trick....maybe?

- Keith

[Charles McCracken]

Keith,

Try a bit like this 50-509:
http://routerbitworld.com/v/vspfiles/v4_backup/product_images/freud_50-509.jpg

These are available from a handful of manufacturers and allow you to always rout with the grain by flipping work piece and template together so you can effectively reverse feed direction without climb cutting.

[Keith Starosta]

That's a nice bit! It would get the job done, for sure. Looks like the standard price for it is $40.99. Ouch...:eek:

Thanks for the info, Charles!! :)

- Keith

[Matt Meiser]

I used a Bosch I bought at Lowes and it worked fine. Watch your fingers though. You need to use a starting pin and based on my bad experience, I believe you need to be able to put the pin on either side of the bit depending on what you are doing at the moment.

[Keith Starosta]

I used a Bosch I bought at Lowes and it worked fine. Watch your fingers though. You need to use a starting pin and based on my bad experience, I believe you need to be able to put the pin on either side of the bit depending on what you are doing at the moment.

Thanks for the tip, Matt. But in my case, I'm going to be using a hand-held router to go around the templates.

[Doug Shepard]

It might be a bit of overkill, as far as the templates are concerned, but I am planning on using 3/4" MDF. Pretty much the only reason I'm doing this is because I have a lot of it on hand, and it's sturdy enough to take a beating. The longest cutting length I've been able to find on a 3/4" diameter flush trim bit it 2". I think this might do the trick....maybe?

- Keith

In hindsight, this might not be an issue with cypress anyway. I've never used it but I think it's one of the softer woods? My thinking was coming from some past experience with some really hard stuff (Ipe in particular) that I needed to do in 2-3 passes to get to depth or I just got too much tearout. Climb cutting, praying, and cursing didn't help with that stuff. If you can enter from the side and do the full thickness, the template thickness wouldn't matter much anyway.

[Steve Clardy]

#2457 or 2458

http://www.routerbits.com/cgi-routerbits/sr.cgi?1186669970_31872+34

[Keith Starosta]

#2457 or 2458

http://www.routerbits.com/cgi-routerbits/sr.cgi?1186669970_31872+34

Thanks, Steve. Those were the two that I was thinking about before Charles led me to that Freud bit. We shall see...

- Keith

[pat warner]

Least amount of tearout and insult?
Use a plunger, collar and new straight bit at least 3/4" in diameter.
Waste at ~1/8 - 3/16/pass. Expect professional results.


Routers (http://www.patwarner.com)

[glenn bradley]

That's a nice bit! It would get the job done, for sure. Looks like the standard price for it is $40.99. Ouch...:eek:

Thanks for the info, Charles!! :)

- Keith

I'd shop for a good price but still, from my experience the Freud will justify its price when it outlasts the $24 bits 3 to 1. I find this with Whiteside too.

For random hogging out I use whatever I have or is on sale but for bits I use a lot (chamfer, 3/8" straight, flush trim) or for those special cuts that have to be right (rail and stile), I spend the money and enjoy the cutters.

[Art Allen]

II know that I'm probably supposed to use a flush trim bit with a bearing, but what diameter, cut length, etc.

I'm going to be using cypress, with the largest thickness being 1.25".

Thanks!!

- Keith

To avoid tearout, you will want to cut WITH the grain. Depending on the grain direction, sometimes you will want the router to ride on the pattern and sometimes on the stock. You will either a bit with both a top and bottom breaking or two bits; one with the top and one with the bottom bearing. The bits with two bearings allow you to avoid changing bits, but if you get the bit with the top and bottom bearing, you will need a cutter length that is greater than the total thickness of the stock and the pattern. The bits with only one bearing require only a cutter length equal to the thickness of the stock. Some cutters have three or even four flutes. The more flutes the finer the cut, but they are more prone to burning. Remove waste as close to the pattern as possible because the less material the cutter has to remove, the better the cut quality.

[Keith Starosta]

To avoid tearout, you will want to cut WITH the grain. Depending on the grain direction, sometimes you will want the router to ride on the pattern and sometimes on the stock. You will either a bit with both a top and bottom breaking or two bits; one with the top and one with the bottom bearing. The bits with two bearings allow you to avoid changing bits, but if you get the bit with the top and bottom bearing, you will need a cutter length that is greater than the total thickness of the stock and the pattern. The bits with only one bearing require only a cutter length equal to the thickness of the stock. Some cutters have three or even four flutes. The more flutes the finer the cut, but they are more prone to burning. Remove waste as close to the pattern as possible because the less material the cutter has to remove, the better the cut quality.

Forgive me here, Art, but is that bolded statement correct? Why would the total cutting length need to be greater than the total thickness of the stock and pattern? If using a double-bearing bit, utilizing the bottom bit (pattern on bottom), wouldn't I only need a cutter whose length is greater than the stock? And when using the top bearing (pattern on top), couldn't I just place some scrap under the stock, raising it off the work surface, so the bottom bearing didn't touch anything?

I hope I didn't muddy these waters...

- Keith

[Noah Katz]

"The bits with only one bearing require only a cutter length equal to the thickness of the stock."

Or not even, if you make multiple passes with different depth settings.

[Charles McCracken]

And when using the top bearing (pattern on top), couldn't I just place some scrap under the stock, raising it off the work surface, so the bottom bearing didn't touch anything?

- Keith

Actually, you would just need to lower the bit when using the end bearing against the pattern on top. Art is correct that with a top bearing bit you could get by with a shorter cut length but you would have to make multiple passes.

[Art Allen]

Forgive me here, Art, but is that bolded statement correct? Why would the total cutting length need to be greater than the total thickness of the stock and pattern? If using a double-bearing bit, utilizing the bottom bit (pattern on bottom), wouldn't I only need a cutter whose length is greater than the stock? And when using the top bearing (pattern on top), couldn't I just place some scrap under the stock, raising it off the work surface, so the bottom bearing didn't touch anything?

I hope I didn't muddy these waters...

- Keith

Keith: You are right. You would only need a cutter length equal to the stock thickness. I am not sure what I was thinking. Sorry.

[Grant Lasson]

Keith,

I made Adirondacks out of cypress and I also used templates (1/4" tempered hardboard I think). Anyway, I had significant trouble on the end grain using a straight flush trim bit. I think a double bearing pattern bit with the carbide set at an angle is your best bet. Here's an example: http://www.infinitytools.com/products.asp?dept=1336

[Keith Starosta]

Thanks for the tip, Grant!!

- Keith

[Cliff Rohrabacher]

I have made a few of them and I just jig sawed them to the line and do a little sanding. The secret is to get a great jig saw. My first great tool was my Bosch and that was 18 years ago and it still cuts great. Also a good round over bit in a router.;) Gary K.

Thasss wot I dun too

[Eddie Darby]

This site has a nice set of instructions for the double-bearing flush trim bit.


http://www.leevalley.com/shopping/Instructions.aspx?p=53401

They also sell them.

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

I like to use my router bits for removing fine cuts, and not for hogging off material, so I either bandsaw the pieces with a bandsaw pattern guide such as this one:

http://www.leevalley.com/wood/page.aspx?c=2&p=30053&cat=1,41036

I set the guide so that it cuts a little bit ( 1/16" or so ) to the outside of the template. If you do this, just remeber to do all your cutting on the same side of the bandsaw blade that is set-up for the extra off-set.

Sometimes I also use masking tape on my bearings for the initial cut, which when the tape is removed, leaves me with a nice thin clean-up cut to finish off with.

[James Biddle]

Nobody recommending a spiral bearing bit? I've had much better luck across end grain with them. Expensive, but nice bits.