Routing techniques?

[Will Goodwin]

I just fired up my router for the first time Sunday night after cleaning up all my scrap from the reindeer. I decided to just play around to get an idea of how this thing (Ryobi router mounted in the table it comes with) works. Well I made a few passes on the 1/2 inch pine scrap and it seemed to be going ok.
Then I actually tried to do something that resembled my first router project and failed miserably. For one I didn't measure anything correctly and secondly, I need some help with router technique (especially on small pieces of wood).
I found out that the router bit is exactly 1/2 inch and the plywood IS NOT! Big surprise to me, probably not to you. I have since found that this is very common...some metric sizing thing and imported wood. Oh well, I digress.
Anyway, I didn't tighten my adjustable fence down well enough and it moved while routing a dado in the plywood so I got a nice wave thing going. Then I have trouble getting the wood onto the second half of the fence (seems to pivot a little on the bit) and then when the back side of the piece clears the first half of the fence it pivots again. Finally, when I tried to route the dado to join the side to the front, I got some serious tear out. I think it may be that I tried to route that one too deep too fast. Any ideas? I am probably not doing anything the correct way with regards to safety as I don't have any idea what I am doing. :saw:
Speaking of that, I need to go back to Klingspor and find out why nobody has called me about the fact that I put my name on the waiting list for the "Basics of Woodworking" class. The guy I talked to the day I went in told me that if I put my name on the waiting list for the class, that the next month, they'd contact the people who didn't get in and have another class.

Oh well here are some pics from my botched attempt at making a box for my sharpening stone (tried to make it so that the stone rides above the box).



thanks for the input,
Will

 

[Trent Mason]

Will,

I have the exact same router and table and I just used it for the first time making my bed a few weeks ago. All I used the table for was making the trim, but I definitely had some tearout and got some "wavy gravy" going on. I did learn that there is a certain way to feed it toward the bit having to do with the grain. If you rout against the grain you will have more tearout. I remember looking at the endgrain and the sides to see how to feed it. I'm sure there are a few thousand people on here that will give you some great advice. Just wanted to say that I feel your pain. :icon_thum

Trent

 

[RayH]

Will,

Woodcraft carrys a set of "plywood grove" router bits that are undersized to fit the standard plywood "nominal" dimensions. Believe they include 1/4, 1/2, and 3/4 "nominal" sizes. I don't remember who makes the bits.

Hope this helps,
RayH

 

[Mike Gilley]

Will,

It looks like your taking the best approach (at least for me anyway) to learning how to use a new tool; play with it :icon_thum until you figure out its quirks.
Now about the tear-out, yes most of that will be caused by an attempt to remove too much material -too deep too fast. As a general rule of thumb you should limit your depth to no more then 1/3 (at the most) of your total cut, going with multiple pass's and increasing your depth with each pass. That will give you the cleanest cust.

Trent is correct about what he said on following the grain on solid lumber. If you go against the grain, it will tear.

Plywood is a bit different, and the surface layer tends to tear quite easily. I have found that I can minimize the tear out on plywood by pre-scoring my cut with a razor, or run the router bit across it, just deep enough to cut the top layer.

Hope this helps,
Mike

 

[Bas]

Hi Will,

Another case of the blind leading the blind here, but I've gone through many of the same issues.

MLCS makes a router bit set for plywood - see my gloat post. Plywood is always undersized, not sure it's a metric thing. The alternative is to use a smaller bit (1/4" or 3/8") and make the dado in two passes. Of course, you're setting the fence twice, so four times as many opportunities for things to go wrong (risk increases exponentially...).

Routing short boards can be tricky with such a wide gap between the two fence halves. Professional / home made fences usually have a much narrower gap, so that the piece is supported on both sides at all times. You may want to use a sacrificial fence instead. I have the same problem with my cheap router table.

As far as tearout goes, I doubt it's because you're taking off too much material at once. But feed rate may be an issue. Where exactly are you getting the tearout, at the beginning and end of the piece? If so, you may want to use a leading/ trailing scrap piece. A little masking tape to hold them together goes a long way.

 

[Joe Scharle]

Then I have trouble getting the wood onto the second half of the fence (seems to pivot a little on the bit) and then when the back side of the piece clears the first half of the fence it pivots again

Off hand, sounds like the bit is proud of the fence combined with too much gap between the fences.
Joe

 

[DavidF]

I am sure you are, but are you pushing the wood through the bit with the fence on your right and the bit rotating anticlockwise (sorry, counterclockwise:roll as you look from the top. When table routing the wood will always try and move the right and this is the side the fence needs to be.

If you are doing it correctly, then check the face alignment of the two halves of the fence. Unfortunately, tear out is a fact of routing life and the only cure is Bas' suggestion of a backup piece.

HTH

 

[McRabbet]

The tearout that you are experiencing in the 3rd photo is caused by several things that you will learn to avoid with experience. This cut is made very close to the end of you box side and the small amount of plywood that is not being cut is not very sturdy. Even in solid wood, this narrow section is vulnerable. Since a router bit is a rotary tool, it applies more side stress than a dado (or tablesaw) blade. Now look at your first picture and you'll see that the fence faces have a wide gap each side of the bit. These gaps need to be minimized by moving each fence face until each is no more than 1/16" from the bit (unplug the router and rotate the bit to insure clearance during setup), while they stay in proper alignment. This will minimize any shifting of the workpiece against the fence (your wavy dado issue) and will reduce added side stress during the cut. (Hold the piece at right angles to the fence is tough anyway and a coping sled may help steady this type of cut). Scribing the cut lines on each side of the dado with a sharp utility knife against a straight edge (e.g., a combination square) will help reduce tearout, and a shallower cut will as well.

In this case, design of your box can be improved by eliminating the dado. Design the box so each side has a rabbet across each end of the piece - make it the width of the thickness of plywood end board and that piece will nestle in between the two sides and you won't have tearout! Keep trying, you'll get it!

BTW -- I generally do this type of cut on a tablesaw with a dado blade (more of a shear cut) and if it is on a router table, then I use a coping sled to hold the piece very steady.

 

[Will Goodwin]

It looks like your taking the best approach (at least for me anyway) to learning how to use a new tool; play with it :icon_thum until you figure out its quirks.
Mike

That's the way I learn...never be afraid to try new things, what's the worst thing that could happen? (Impale myself with flying wood?).

Routing short boards can be tricky with such a wide gap between the two fence halves. Professional / home made fences usually have a much narrower gap, so that the piece is supported on both sides at all times. You may want to use a sacrificial fence instead. I have the same problem with my cheap router table.

Ahem .. what's a sacrificial fence? I am thinking about building my own fence if this one doesn't work for me. The plastic tube at the top for a vaccuum hose leaves a lot to be desired. I found that the dust was being thrown out the leading edge of the dado....there was sawdust everywhere on that wall :rolf:!

Just wanted to say that I feel your pain. :icon_thum

Thanks Trent for the sypathy!

I would do that on my table saw.

If I only had that option...still putting together a shopping list. I don't have a table saw yet. The wife said she is fully prepared for me to come back from the shop crawl with a list of tools that I want to buy and the basic prices.

I am sure you are, but are you pushing the wood through the bit with the fence on your right and the bit rotating anticlockwise (sorry, counterclockwise:roll as you look from the top. When table routing the wood will always try and move the right and this is the side the fence needs to be.

If you are doing it correctly, then check the face alignment of the two halves of the fence. Unfortunately, tear out is a fact of routing life and the only cure is Bas' suggestion of a backup piece.

HTH

Actually, I was standing facing the router table as you see in the picture and feeding the wood from right to left across the fence. Is that correct? I put some slight downward pressure on the work piece and pushed it forward against the fence and fed it to the left.

The tearout that you are experiencing in the 3rd photo is caused by several things that you will learn to avoid with experience. This cut is made very close to the end of you box side and the small amount of plywood that is not being cut is not very sturdy. Even in solid wood, this narrow section is vulnerable. Since a router bit is a rotary tool, it applies more side stress than a dado (or tablesaw) blade. Now look at your first picture and you'll see that the fence faces have a wide gap each side of the bit. These gaps need to be minimized by moving each fence face until each is no more than 1/16" from the bit (unplug the router and rotate the bit to insure clearance during setup), while they stay in proper alignment. This will minimize any shifting of the workpiece against the fence (your wavy dado issue) and will reduce added side stress during the cut. (Hold the piece at right angles to the fence is tough anyway and a coping sled may help steady this type of cut). Scribing the cut lines on each side of the dado with a sharp utility knife against a straight edge (e.g., a combination square) will help reduce tearout, and a shallower cut will as well.

In this case, design of your box can be improved by eliminating the dado. Design the box so each side has a rabbet across each end of the piece - make it the width of the thickness of plywood end board and that piece will nestle in between the two sides and you won't have tearout! Keep trying, you'll get it!

BTW -- I generally do this type of cut on a tablesaw with a dado blade (more of a shear cut) and if it is on a router table, then I use a coping sled to hold the piece very steady.

Thanks McRabbet .. I'll try your suggestions. I'll also try making my box using the rabbeting bit. I also need to try out my dovetail bit...anybody have any suggestions on how to cut dovetails on a table? I suppose I can take the router out of the table and try to free hand it, but I'd like to try with the table.

thanks,
Will

 

[Bas]

Ahem .. what's a sacrificial fence?

It's a fence you sacrifice to the Tool Gods, in the hope that your Skil tools are transformed into Festool

The problem with your router fence is that the two halves are too far apart. This is because it needs to accommodate lots of different bits, from the small 1/4" straight bit to the big honkin' panel raisers (well, in theory anyway - I doubt anyone would use this kind of table for serious panel raising work).

You need an adjustable fence to solve this. Basically you want to set the opening just wide enough for the bit you're using. But, those fences are expensive, or somewhat complicated to make.

A simpler option is a sacrificial fence. This is nothing but a straight board. Clamp it to your existing fence, start the router with the desired bit, and push the fence into it (slowly!). Or pre-cut/ drill/ saw the opening. This will give you a space for the bit to sit, but with the smallest possible distance between the two fence "halves".

Here's a picture from onlinetoolreviews.com, that might help. Just imagine this is one board, no two halves:

You can do something similar with the table saw. Let's say you have a 1/2" dado blade set up, and you want to make a 3/8" dado. Clamp a straight board to your fence, start the saw, and push the fence into the blade. By partially burying (that's the term...) the dado blade, you can now make narrower dado's.

UHMW is a popular material for making sacrifical fences. It's the white high-density plastic that's often used for cutting boards.

 

[Will Goodwin]

Ouch Mike that looks painful. What happened? Freak typing accident?

 

[DavidF]

Actually, I was standing facing the router table as you see in the picture and feeding the wood from right to left across the fence. Is that correct? I put some slight downward pressure on the work piece and pushed it forward against the fence and fed it to the left.

Sounds right; not very ergonomic, but at least the correct direction.

 

[DavidF]

It's a fence you sacrifice to the Tool Gods, in the hope that your Skil tools are transformed into Festool

The problem with your router fence is that the two halves are too far apart. This is because it needs to accommodate lots of different bits, from the small 1/4" straight bit to the big honkin' panel raisers (well, in theory anyway - I doubt anyone would use this kind of table for serious panel raising work).

You need an adjustable fence to solve this. Basically you want to set the opening just wide enough for the bit you're using. But, those fences are expensive, or somewhat complicated to make.

A simpler option is a sacrificial fence. This is nothing but a straight board. Clamp it to your existing fence, start the router with the desired bit, and push the fence into it (slowly!). Or pre-cut/ drill/ saw the opening. This will give you a space for the bit to sit, but with the smallest possible distance between the two fence "halves".

Here's a picture from onlinetoolreviews.com, that might help. Just imagine this is one board, no two halves:

You can do something similar with the table saw. Let's say you have a 1/2" dado blade set up, and you want to make a 3/8" dado. Clamp a straight board to your fence, start the saw, and push the fence into the blade. By partially burying (that's the term...) the dado blade, you can now make narrower dado's.

UHMW is a popular material for making sacrifical fences. It's the white high-density plastic that's often used for cutting boards.

He has an adjustable fence, maybe those slots can be extended to allow the fence halves to come closer together

 

[cpowell]

Will, most importantly, get in the habit of using push blocks and featherboards. I use them. A router bit can eat fingers, as Mike has demonstrated so graphically.

I have had 2 experiences routing dados where a straight router bit grabbed the stock and slung it VERY quickly from right-to-left. So long as the stock is held to the fence (with featherboards) the likelihood is very low.

Let's say you're routing a dado in multiple passes, adjusting the depth each pass, and want to end up with a 1/2 inch deep dado. On your final pass the stock comes away from the fence slightly. The bit will grab the side wall of the dado nearest the fence, almost like a trapped cut, and it will accelerate the stock and sling it very fast. As I mentioned before, I have had that happen twice. The first time I was pushing the stock by hand. My hand came very close to the bit. Scared the crap out of me (not literally).

I love using the RT but I use hold downs, featherboards and push blocks/push sticks...all the time.

I have never had this happen when hand routing. Only cutting dados on the router table "with the grain". Just be very aware of the fact that that bit has very little trouble eating into hardwood.

I personally think that most WWers have a lot of respect for that spinning blade above the TS and are conscious of where there hands and body are with respect to the blade and the stock

Routing right-to-left with normal edge-shaping bits do not have this same risk but I still use featherboards and push blocks.

'nuff said about safety.


One thing to add - good quality bits make a big difference when routing. I bought a few cheap bits and a cheap "set" starting out. As I wore them out I replaced the commonly used (by me) bits with Freud/Whiteside bits.

And practice makes [STRIKE]scrap[/STRIKE] perfect.


Chuck

 

[DavidF]

One thing to watch when routing dados wider than the bit and taking two passes is to route to the right hand line first and then move the fence to the right by the appropiate amout to route to the final width. This way the wood is still being pushed against the fence. If you do it the other way round you are climb cutting the right hand side with no support from the left and the wood will try and move away from the fence, giving at best a bad dado and at worst shoot off the back of the RT.

 

[Will Goodwin]

Point taken guys....sorry about your finger Mike, but I'm glad they were able to get you patched up. Anyone got any templates for featherboards and pushblocks/sticks?

And Bas - where do you get UHMW?

Will

 

[Canuck]

And Bas - where do you get UHMW?

Will

Here ya go Will........

http://www.woodcraft.com/family.aspx?familyid=897

There are other sources too ... MLCS, Rockler, Hartville etc..

Wayne

 

[Bas]

Haven't had to purchase any yet (free is always better ), but McMaster-Carr has a good selection of UHMW products in a variety of widths, thicknesses and lengths. You can also get it at the usual lineup of WW stores (e.g. Rockler)

 

[LeeNC]

Time for my $0.0002 (at today’s $ value). I would recommend one of the router how to books. Lonie Bird, Pat Warner, and Bill Hylton all have good books in this category. My first was Bill’s "Woodworking With The Router". Pat Warner has a lot of info on his website at www.patwarner.com.

LeeNC