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Avoiding Tearout On A Router... From Wayne Guitars


bigdguitars
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Ok so now that my router is running I am getting some tear out on my wood...

I saw this movie on wanyne guitars and I am trying to figure out why that bushing makes a difference?

http://www.wayneguitars.com/movies/clip379.mov

Does it pull less wood off? But if you cut close to the orginal line wouldn't that work too?

I know that going slow and taking less off reduces the tear out but he is feeding sooooo fast in this video?

Thanks!!!

-Derek

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Gemleggat is right. The bushing simply slips over the pin in the table and allows you to shape the body just slightly oversized. You then remove the bushing and make a final pass with just the pin. This way the final pass only takes off a very small amount of wood.

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I have two suggestions to avoid tearout. One is use a shear bit (or a spiral bit). This type of bit slices and does not tear out as much. I cut the full 2" in one pass with these without problems. The second suggestion is cut as close to your final size as possible. If you have a good bandsaw cut 1/16" oversize and no more. The less your router has to remove the smoother the cut will be.

~David

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My opinion would be to stop looking for shortcut answers and learn how to use your tools.

I just think you need to learn how to use YOUR router and don't worry about what some company is doing, you're not a company, and any router in the right hands will do a superb job. The emphasis being on the right pair of hands that have experience using tools.

Stop trying to hurry the process, get 'organic' with your router, i.e., work -with- it, don't try to force it to do things it can't do, and practice, something I don't think you like to do a lot of. Think of your router as another hand. You wouldn't stick your hand on an open burner, would you? Stop mis-using your router and you'll be fine, but you need time and practice to find out it's limits and maturity to learn not to force it past it's limits.

Sorry to be direct, but I've seen a lot of your work, and it doesn't look like you do much practicing on scrap, you just bore right into the guitar whether you know what you're doing or not, and you want it to come out perfect the first time, the hallmark signs of a lack of patience. I suffer from this dreaded affliction also, and it has bitten me in the ass more times than I care to admit, but I learned, just like you're doing, but when you're in the middle of learning something, you can't really 'see' it, you see it much more clearly in hindsight.

I use -many- techniques and methods with my router. Sometimes I go forwards, sometimes backwards (actually, I go backwards more often than forwards for some things), sometimes full-bore cuts, sometimes many small cuts, sometimes thick passes, sometimes light passes. it's the voice of experience talking to me that tells me how to approach certain functions, but it's the same router, same bits, different day.

And I got a lot of tearout too when I was first starting out, but I didn't look for a magic bullet, I figured I just needed to learn what the hell I was doing, which was true.

So stop looking elsewhere for an answer, the answer is right inside of Y.O.U.

You need to learn to settle down, gain some patience, and take some time out to practice on some scrap pieces before you approach the guitar.

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Tearout is caused by asking the bit to do to much regardless of how deep a pass you taking. Its a combination of the bit, depth, how much per pass ,router power and care and attention!! If you take your time taking a little off per pass you wont get tear out. I spend the whole time while routing listening the to motor, you can learn whats happening/gonna happen by doing that.

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Tearout is caused by asking the bit to do to much regardless of how deep a pass you taking. Its a combination of the bit, depth, how much per pass ,router power and care and attention!! If you take your time taking a little off per pass you wont get tear out. I spend the whole time while routing listening the to motor, you can learn whats happening/gonna happen by doing that.

Exactly, but not exclusively.

You could relate a router's performance against the wood you present it by comparing it to a scraper when you're scraping a carved top.

Sometimes when scraping, you have to change your 'attack' angle in order not to 'tear out' wood roughly, ...depending on where you are on the top and the orientation of the grain at that point... to get a nice clean shaving.

And so it is with a router. Sometimes I have to go 'backwards' when approaching certain parts of the body/grain, usually this is in the middle of the body, it seems tearout happens most frequently to me in that area. I will travel the router in reverse, taking a -lot of light passes-, until I get to the -very- -last- -pass-, then I go forward, and I have eliminated a large amount of tearout problems doing it this way.

But that's because I've done a ton of them, and the voice of experience is talking to me, and it is not telling me to find a different bit, but to instead, work on -myself- and my expertise...to gain 'tactics', 'tricks', and 'methods' to achieve my goals, which I gained by Practicing. :D

Over, and over, and over, and over, and over again.

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And so it is with a router. Sometimes I have to go 'backwards' when approaching certain parts of the body/grain, usually this is in the middle of the body, it seems tearout happens most frequently to me in that area. I will travel the router in reverse, taking a -lot of light passes-, until I get to the -very- -last- -pass-, then I go forward, and I have eliminated a large amount of tearout problems doing it this way.

I was sooo pissed when I tore the hell out of the tele neck I was trying to rout out. I had the right tool, the right bit, the right template, everything. What I didnt have was experience, none. This was the first time I tried this. So, I read up on climb cutting and thought, "sweet, I got this". Neck #2, what happens? I screw this one up too but now I KNOW how to climb cut. Nothing that you read or see or are told holds a candle to really actually doing somthing. Sure, you can get some direction from instruction but you cant expect to attack somthing with only the things you have read. You have to practice. I am now on my 3rd and 4th necks and while I now have the routering :D down, I am still figuring out other aspects of neck construction. I realize that probably seems pretty obvious, but I still have to remind myself that doing is much more valuable than thinking about how to do it.

I too think that being direct is much more valuable in most cases than tip toeing around the issue and surgar coating things. When I was saturating all the woodworking forums asking about climb cutting with my router I honestly think that if someone would have told me to shut the hell up and just try it, I would have had a neck about three weeks sooner. Your just wasting your time talking about it after a certain point.

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I agree that practice is valuable.

Proper learning has to be a combination of both, and jay5 has it right on the money He read up about a technique, then tried it-- failed once, but learned as he went. At some point in time he probably had a tearout, but 'felt' what he was doing wrong, and continued with the rest of the rout just to keep practicing the technique. By the end of it, he probably went, "AHA! Now I see what you need to do."

It was a combination of having read up on something and THEN trying it out in practice. You can't JUST practice and expect to progress at anything more than a snail's pace (though of course you WILL progress... that's the nature of practice!). If Drak only wants to learn by practice, that's his prerogative. It's a valid way to learn. But it's not the quickest, and nor is it the ONLY way to learn. By the same token, and even moreso, you can't JUST read something and expect to be able to do it right out of the gate.

There are those of us who simply don't have scraps to practice on a million times. I don't know if Big D is one of them, but I sure am.

In the interest of both demonstrating my point AND contributing to the thread--

I have only worked on one project so far. No "practice practice practice" for me, and no scrap wood (other than construction lumber, which hardly counts) to practice on anyhow. BUT, because I'm very deliberate, ask a lot of questions, and try to apply what I've read as I go, I've had successes so far. Any small tearouts I've had have been from ignoring advice and (one of Drak's well-taken points!) being impatient. Techniques learned and then applied:

1. roughing as close to final shape as possible

2. 'back'-routing sensitive areas in tiny tiny passes

3. listening to and feeling for the router's motor's performance

----

I'm sure it goes without saying that you need a sharp bit, too. Otherwise you just have a thin "not so sharp" bit of metal banging into the wood and removing it by brute force.

Greg

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Sometimes when scraping, you have to change your 'attack' angle in order not to 'tear out' wood roughly, ...depending on where you are on the top and the orientation of the grain at that point... to get a nice clean shaving.

And so it is with a router. Sometimes I have to go 'backwards' when approaching certain parts of the body/grain, usually this is in the middle of the body, it seems tearout happens most frequently to me in that area. I will travel the router in reverse, taking a -lot of light passes-, until I get to the -very- -last- -pass-, then I go forward, and I have eliminated a large amount of tearout problems doing it this way.

I've noticed the scraper thing while doing my violin.

The thing about going backwards with a router, isn't that common sense? I learned that LONG ago. It's pretty noticable when you are rounding over egdes to go backwards in some areas. Basically, look at the direction of the grain along the shaping of the body's edges/sides, and how it relates to the router bit. The router bit is no different that any other cutting tool, such as a chisel, and if you cut against the grain, you will most likely get tearout. Obviously with a router you can't re-orientate the piece to cut with the grain (unless you want to flip over the body and reset your temps), so you must go backwards.

When you do go backwards, however, and especially when doing sides, make sure you have GOOD control of your router, or body, depending on how you are cutting it, because the bit will 'grab' when going backwards.

Myka's tip is very good. I think the 'shear' bit he's refering to is also known as a 'rake'. The cutters have a positive 'rake', or angle of a few degrees (I've seen some with 4 degree rakes) to them.

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Also, I believe that the direction of the 'rake' / 'spiral' is important. You want to make sure you get one that will pull your wood toward the collet, not push it away. That's just something I'm going on from memory, though, and it might be a poor memory. Someone can correct me if I'm wrong and there's no way to get one that spirals in different directions. :D

Here's one I found at Grizzly:

Example of shear cutting bit on this page

Greg

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Does it pull less wood off? I know that going slow and taking less off reduces the tear out but he is feeding sooooo fast in this video? 

Yes, he says in the video it reduces tearout in the critical areas. I actually don't think he's feeding terribly fast, you could see on the close-up near the end he's taking light cuts.

My opinion would be to stop looking for shortcut answers and learn how to use your tools.

The fact of the matter is, BigD bought a rediculously large, expensive and IMO, excessive machine and he doesnt really know how to use it. You NEED to practice with the tools you have.

I agree with both these quotes. It seems like you're looking for short cuts to pump out bodies to stick on ebay, yet you haven't fully mastered actually building a high quality instrument, from what I've read in your threads in the progress section.

It's like like you haven't even got your licence, yet you plan on racing in the indy 500. My advice would be to slow down. Master the use of 'home workshop' tools, and you will have a much easier time with industrial sized equiptment, if/when that time comes.

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I have been reading here and asking questions and it has made my first attempts very easy and they came out very well, I haven't got too much in the way of the router experience but that is my next objective.

I know there are a lot of places that sell router bits and I've read that a few people don't like the Home Depot ones, and I also read that Lowes sells some but I haven't heard if they were any good. Any opinions on these? I would like to be able to go down to a store to pick them up if possible, rather than buy from the web. The web is a great resource but I like to be able to pick it up and check it out before I buy and be able to make returns and exchanges easily and without paying for shipping, return shipping, and restocking fees when they apply. I do buy from the web when necessary though.

Also another router question is what would be better for keeping tear out to a minimum a 1/4 collet or a 1/2 collet, my router came with both and I was unsure of what would be better. I see more 1/4 at the stores but I know 1/2 is very common as well and more expensive. Would the wider collet be more stable or would it cause bigger tearout? I don't have the money to buy both to compare to find out so any help would be much appreciated!

Jason

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I don't know for a fact, but I suspect that the bits at Lowe's will be from the exact same factory as those from Home Depot. Home Depot (and probably Lowe's!) also carry Freud bits, though, which have a pretty solid reputation. One of my template bits is a Freud that's been working fine (though I haven't compared it to anything else yet) and the other one (bearing at the bottom instead of top) is a Lee Valley jobbie, so I'll at least have some sort of basis for comparison if/when I ever get around to using it.

Surely the 1/2" collet will be more stable, no?

Greg

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One more question, I will be routing on some purpleheart soon after a little practice, and I am worried about the hardness of this wood. I know there are bits with different amounts of flutes which I think are the blades, so for this hard wood what would be best? I've seen single flutes, 2 flutes, and some new ones with three flutes. I just don't know if more or less will help with harder woods. So if anyone has some ideas let me know. Thanks for the help! Jason

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One of our submarines is missing tonight

Seems she ran aground on manoeuvres

One of our submarines

A hungry heart

To regulate their breathing

One more night

the Winter Boys are freezing in their spam time

The Baltic moon

Along the northern seaboard

And down below

The Winter Boys are waiting for the storm

Bye-bye empire, empire bye-bye

Shallow water - channel and tide

And I can trace my history

Down one generation to my home

In one of our submarines

One of our submarines

The red light flicker, sonar weak

Air valves hissing open

Half her pressure blown away

Flounder in the ocean

See the Winter Boys

Drinking heavy water from a stone

Bye-bye empire, empire bye-bye

Shallow water - channel and tide

Bye-bye empire, empire bye-bye

Tired illusion drown in the night

And I can trace my history

Down one generation to my home

In one of our submarines

One of our submarines

One of our submarines

One of our submarines is mis

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One of our submarines is missing tonight

Seems she ran aground on manoeuvres

One of our submarines

A hungry heart

To regulate their breathing

One more night

the Winter Boys are freezing in their spam time

The Baltic moon

Along the northern seaboard

And down below

The Winter Boys are waiting for the storm

Bye-bye empire, empire bye-bye

Shallow water - channel and tide

And I can trace my history

Down one generation to my home

In one of our submarines

One of our submarines

The red light flicker, sonar weak

Air valves hissing open

Half her pressure blown away

Flounder in the ocean

See the Winter Boys

Drinking heavy water from a stone

Bye-bye empire, empire bye-bye

Shallow water - channel and tide

Bye-bye empire, empire bye-bye

Tired illusion drown in the night

And I can trace my history

Down one generation to my home

In one of our submarines

One of our submarines

One of our submarines

One of our submarines is mis

Thomas Dolby - great track :D

Back on topic, there is a huge difference in the router bits and techniques required when using a pin router compared to a hand held or table router.

Derek, this is how I do it and it works for me but as Drak sez practising the tecnique on scraps (it won't take long) is the way to go.

1. Bandsaw as close to outline as you dare, Just as David suggests.

2. Use solid carbide spiral end mills - available from any good engineering supply house ( J&L industrial, even grizzly keep them). With a true spiral cutter there is always an edge in contact with the wood rather than the chunk by chunk approach of a conventional router bit. My personal preference when router the perimeter is for a four flute cutter but these generally are not centre cutting so you can't plunge cut with them. I then change to a shorter three flute centre cutting end mill to route the cavities.

here's a four flute

f7098032.jpg

3. I use a 1mm oversize pin first time around and this cleans up the areas where I'm not quite close enough with the bandsaw. I also take this cut in three steps increasing the depth each time around - if the maple top is very thick I may take four cuts.

4. I then replace the pin to one the same size as the cutter, if the body is all mahogany I'll take the final cut in one pass but if there's a lot of maple again I'll make several passes. Also you may want to practise climb cutting (reversing the direction) on the four areas prone to tear out - the tips of the horns and the corresponding positions on the upper and lower bouts.

A pin router is a very powerfull tool, especially a large one such as yours, use it to work with the wood not overpower it.

These two are as routed (the upper one still needs final thicknessing) with zero tearout even around the horns and as you can see the tops are both thick and highly quilted.

P1010005_1.jpg

just my 0.02

Neil

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