router bit question...

[steveg]

Hmm...nice call, Loring. I see what you are saying...mpc mentioned that I might have a bit of trouble with doing the second cut on the other side of the board, given that I will be dealing with a bearing running along an edge that was just rounded off by the prior cut/pass with the router. SO -- combining that with what you are pointing out with the Skil bit...hmm. I can see where that bearing might be running "under the ridge," so to speak, on that second pass.

Hmm...I went to the mlcs site, and looked at their "non-premium" bits...not the Katana bits, and I'm not sure that one looks much different from the Skil, with what appears to be a similar gap above that bearing...

http://www.mlcswoodworking.com/shops...ound_over.html

I need to take a look at that bit of my dads, see if it's a 3/8" radius, see how sharp it is, run a piece of scrap, and see how it does. If it won't work, I may have to just spring for the premium bit...

I can also find some "full bullnose" bits, that would make the full rounded edge in one pass. Negatives are cost, and that all are 1/2" shank to get the 3/8" radius (3/4" diameter). I have not found a 1/4" shank bit that will do a radius larger than 1/4"...

Steve

[cabinetman]

Hmm...nice call, Loring. I see what you are saying...mpc mentioned that I might have a bit of trouble with doing the second cut on the other side of the board, given that I will be dealing with a bearing running along an edge that was just rounded off by the prior cut/pass with the router. SO -- combining that with what you are pointing out with the Skil bit...hmm. I can see where that bearing might be running "under the ridge," so to speak, on that second pass.

Hmm...I went to the mlcs site, and looked at their "non-premium" bits...not the Katana bits, and I'm not sure that one looks much different from the Skil, with what appears to be a similar gap above that bearing...

http://www.mlcswoodworking.com/shops...ound_over.html

I need to take a look at that bit of my dads, see if it's a 3/8" radius, see how sharp it is, run a piece of scrap, and see how it does. If it won't work, I may have to just spring for the premium bit...

I can also find some "full bullnose" bits, that would make the full rounded edge in one pass. Negatives are cost, and that all are 1/2" shank to get the 3/8" radius (3/4" diameter). I have not found a 1/4" shank bit that will do a radius larger than 1/4"...

Steve

The problem with the second pass was covered well by mpc's suggestion about using a fence. It's a simple thing to do to a table. It will register the depth of cut to the edge of the subject piece. It will also prevent you from accidentally running the bit off the long edge and turning the corner, if used handheld. Bits used with a fence don't depend on the use of a bearing.

My suggestion would be to do a test sample with a fence. With the board laying on the table that will allow the bit height adjustment to orient its cut to finish near flush with the face that's down...that won't change with whatever thickness the board is. The fence adjustment for in and out will be for how the outer edge finishes off.

If by chance you do the machining with a handheld, and the second pass leaves a small ridge, a block sander can shape it pretty quick.

If the bits you have for a radius cut are HSS (high speed steel) they will likely not be ones with a bearing. Roundover bits with carbide tips and ¼" shanks can go up to ½" radius in many brands. See this chart.


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[steveg]

The problem with the second pass was covered well by mpc's suggestion about using a fence. It's a simple thing to do to a table. It will register the depth of cut to the edge of the subject piece. It will also prevent you from accidentally running the bit off the long edge and turning the corner, if used handheld. Bits used with a fence don't depend on the use of a bearing.

True...as I think about this, no need for a bearing if you are using a fence...

...OK, fence/table is necessary for this cut.

My suggestion would be to do a test sample with a fence. With the board laying on the table that will allow the bit height adjustment to orient its cut to finish near flush with the face that's down...that won't change with whatever thickness the board is. The fence adjustment for in and out will be for how the outer edge finishes off.

Yes...as I'm picturing this, if I want my 3/4" thick stock to end up 12" wide (measured from the back "flat edge" of the board to the outermost point of the curved edge on the front of the board), then I'd set my router/table so that the bit is set to a depth such that the rounded portion of the bit is flush with the tabletop. Then, I would set my fence 11 5/8" from the "cutting tip" of the blade that is nearest the fence (which would put the "cove" portion of the blade 12" from the fence. Then, running the board through, flipping it, and running it through again would theoretically give me a perfect edge on the "long" side of the board.

If the bits you have for a radius cut are HSS (high speed steel) they will likely not be ones with a bearing.

I'm not sure if they are carbide, or not. BUT -- the roundover bits, for example, are strange. They consist of a shank that is threaded on the bottom of the "blade" -- and then there is a screw-in bearing you can use IF YOU WANT. Never seen this before, except with this bit set (Craftsman, I believe).

Roundover bits with carbide tips and ¼" shanks can go up to ½" radius in many brands. See this chart.

Yes, I can find roundover bits that do go up to 1/2" radius with 1/4" shank; I was referring to the FULL "bullnose," or "180-degree semi-circle edge" bits -- the ones that are made to do the entire "rounding off" with one pass, not the "1/2 rounding off" that a normal roundover bit will do. BUT, since I wrote that, I do think I found one that will do a 3/8" radius (3/4" diameter), here...

http://www.mlcswoodworking.com/shops...s/bt_bull.html

It would be bit #5464 on that top chart...

Would this be an easier bit to use for my application, or is it kind of a "six of one, half dozen of the other" scenario, when comparing this bit to a roundover bit?

Steve

[LCHIEN]

you can use a bullnose bit as well, its kind of more a specialty bit... a roundover bit can be used for many things, including bullnose, the bullnose can only be used for that. If you don't plan on buying a lot of bits, a roundover is much more useful to have.

A bullnose must be used with a fence. - again, several passes would be my recommendation. The bearings on a rondover are removable if you want...

Actually you can use a roundover or any bit with a bearing with a fence, for full cut depth you use a thin straightedge and set the fence and bit so that the bearing just contacts the straightedge when laid across the face of the fence.

As for saving work, an equal amount of wood in the end is removed in both bits. For a bullnose you would take shallower, but more passes since each pass takes some off the bottom and the top.

[cabinetman]

A full bullnose bit can be used in a handheld router if necessary if you use a straight edge clamped to the stock, and the stock is clamped to the bench. Depending on the species, a few inboard adjustments should be made instead of a full cut. A problem with that bit design, is that the stock has to be thicknessed or be the correct thickness to allow for cleanly machined faces.

If the stock is slightly thicker, it will leave a reveal. If it's thinner it will not produce a proper bullnose.

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[LCHIEN]

A full bullnose bit can be used in a handheld router if necessary if you use a straight edge clamped to the stock, and the stock is clamped to the bench. Depending on the species, a few inboard adjustments should be made instead of a full cut. A problem with that bit design, is that the stock has to be thicknessed or be the correct thickness to allow for cleanly machined faces.

If the stock is slightly thicker, it will leave a reveal. If it's thinner it will not produce a proper bullnose.

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good points

[cabinetman]

good points

Thanks.

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[LCHIEN]

This is controversial but I might point out for a beginning router user the offering of these router bit sets:

Here's the 15-piece set from MLCS in a nice storage box for $40 (free shipping, no tax). and it includes the 3/8" roundover bit you want. plus an assortment of roundover, coves, straight (grooving bits) and other useful profiles. Works out to $2.66 per bit as they say which means even if you use three of them in its lifetime you are probably ahead. THese are not rejects or lower quality bits but from their main line of bits. http://www.mlcswoodworking.com/shops...et15piece.html

As I said many love these sets and many hate them, I am a fan but I'll try and list the arguments fairly:

Pros
selection of many bits saves a lot of money so even if you use a few you are ahead
selection of bits promotes trying different profiles to see which looks the best rather than buying a bit to do the job sight unseen - encourages experimentation.
From their standard line of bits, the quality is very good (so called premium bits may last longer because of better carbide and make cleaner cuts for a longer time)-good enough for casual use, limited use
If you find you use a bit a lot, replace it with a premium bit.
Nice organized storage box
saves time not having to wait for an ordered bit to come.

Cons
Too many bits you'll never use them all, a waste buying those you don't use
not the prime quality bits
large outlay of money, prefer to buy as you go


I've had the MLCS 30-piece set for $100 (free shipping, no tax) for many years and used perhaps half or more of them (I can tell by the ones that still have the protective rubber coating). If you figure the average cost per bit bought individually is around $10 then I've gotten $150 value from the box and still have more bits as a bonus.
http://www.mlcswoodworking.com/shops...et30piece.html

others sell similar sets but I've come to appreciate the relative quality, service and convenience and free shipping/no tax of MLCS. If you have any problems even your fault, I've come to expect they'll ship a free replacement with no questions. I think you can also order MLCS sets thru Amazon.

So if you are spending $15 on one bit, you might consider spending $40 on 15 bits... if there's a chance you might ever need two more common bits...

[cabinetman]

This is controversial but I might point out for a beginning router user the offering of these router bit sets:

Here's the 15-piece set from MLCS in a nice storage box for $40 (free shipping, no tax). and it includes the 3/8" roundover bit you want. plus an assortment of roundover, coves, straight (grooving bits) and other useful profiles. Works out to $2.66 per bit as they say which means even if you use three of them in its lifetime you are probably ahead. THese are not rejects or lower quality bits but from their main line of bits. http://www.mlcswoodworking.com/shops...et15piece.html

As I said many love these sets and many hate them, I am a fan but I'll try and list the arguments fairly:

Pros
selection of many bits saves a lot of money so even if you use a few you are ahead
selection of bits promotes trying different profiles to see which looks the best rather than buying a bit to do the job sight unseen - encourages experimentation.
From their standard line of bits, the quality is very good (so called premium bits may last longer because of better carbide and make cleaner cuts for a longer time)-good enough for casual use, limited use
If you find you use a bit a lot, replace it with a premium bit.
Nice organized storage box
saves time not having to wait for an ordered bit to come.

Cons
Too many bits you'll never use them all, a waste buying those you don't use
not the prime quality bits
large outlay of money, prefer to buy as you go


I've had the MLCS 30-piece set for $100 (free shipping, no tax) for many years and used perhaps half or more of them (I can tell by the ones that still have the protective rubber coating). If you figure the average cost per bit bought individually is around $10 then I've gotten $150 value from the box and still have more bits as a bonus.
http://www.mlcswoodworking.com/shops...et30piece.html

others sell similar sets but I've come to appreciate the relative quality, service and convenience and free shipping/no tax of MLCS. If you have any problems even your fault, I've come to expect they'll ship a free replacement with no questions. I think you can also order MLCS sets thru Amazon.

So if you are spending $15 on one bit, you might consider spending $40 on 15 bits... if there's a chance you might ever need two more common bits...

Money wise the small sets make sense. But it gets me thinking how good is a bit worth $2.66 each, when spinning at 20K - 30K RPM's?

Like most that have kits, some bits never get used.

.

[mpc]

Yes...as I'm picturing this, if I want my 3/4" thick stock to end up 12" wide (measured from the back "flat edge" of the board to the outermost point of the curved edge on the front of the board), then I'd set my router/table so that the bit is set to a depth such that the rounded portion of the bit is flush with the tabletop. Then, I would set my fence 11 5/8" from the "cutting tip" of the blade that is nearest the fence (which would put the "cove" portion of the blade 12" from the fence. Then, running the board through, flipping it, and running it through again would theoretically give me a perfect edge on the "long" side of the board.

The bold-faced highlighted portion of your post concerns me. What you are describing is the following order:
router bit - workpiece - table fence
That means the workpiece is trapped which is a recipe for kickback and other problems. Imagine the workpiece being slightly fatter (say 12.1 inches) at its midpoint and a proper 12.0 inches at the start end end... that means you'll be pushing outwards on the router bit during the cut. If the bit has a bearing, you will be FORCING the bit sideways (further from the fence) bending and likely breaking the bit. At 20,000 RPM. If the bit doesn't have a bearing you'd still be shoving against the bit. Any operation where the workpiece is "trapped" between a cutter & fence is often a bad idea. It's possible the bit can snag on the workpiece and try to force it backwards too. With the bit half-buried in a mouse hole style fence, there is nothing on the opposite side of the workpiece to forcefully jam it against the bit other than your hands. If the bit does snag something the workpiece can still move away from the bit (assuming your hands are applying nominal force levels - you don't gorilla-shove the piece into the fence!). See Loring's (LCHIEN) reply #9 earlier in this thread for similar warnings.

This trapped issue is just like the bad idea of using a table saw's miter fence to push a workpiece while the main fence guides the far end on the other side of the blade. Once that far end is cut off there is nothing preventing it from vibrating into the blade and getting launched back at you. That's why you see folks clamp a small wood block to just the beginning of the fence: this registers the end of the workpiece (for repeatable length) but by the time the workpiece gets to the blade there is now a gap between the workpiece end and the fence so there are no "trapped" issues and the cutoff just sits there.

Are you making roundovers on just the front edge of these stair treads or along one/both sides too? Your post leads to believe you only need to roundover the fronts. If that's the case, I'd rough-cut the stock to over 12 inches wide, make the roundovers along the just-cut (and hopefully straight) edge using a router table + simple mouse hole fence (don't need the router bearing other than to use as a reference for positioning the fence), then make a final cut on the stair's back edge at the table saw to set the final 12 inch dimension. This way, if the routing operation tears out or has issues, you can simply table saw it off and try again. Once the roundover is complete, the final pass at the table saw is far more likely to be a problem-free cut so make that your final 12.0 inch dimensioning cut. If you start with a 12.0 inch wide workpiece and the router tears out a chunk... you've got firewood.

mpc

[mpc]

To add a bit more:
To set your router fence - assuming a mouse hole fence like Cabinetman's lower one - I'd do a two-step procedure:
1: Have the bearing completely inside the mouse hole initially... so that only a portion of the bit actually makes a cut. Make one pass of all your workpieces this way, plus a few scrap/practice workpieces made from the same thickness stock. Flip the workpiece & practice ones over and make the second pass. You'll have rounded edges with a flat area between them.

2: With the router off & unplugged, use a straight edge to bridge the mouse hole. Slowly move the fence until that straight edge just kisses the bit's bearing. Lock the fence down. Run one scrap/practice work piece past the bit, turn it over, and make the second pass. Examine the final shape and tweak the bit height if needed (little ridge cuts left at the ends of the roundovers means the bit is too high out of the table, lousy tangents to the faces of the treads means the bit is too low, etc.) And, if the cuts tried to tear out, repeat step 1 again with more of the bit exposed. Several shallow cuts will make a cleaner cut than trying to hog out the entire roundover in 1 or 2 cuts. Step #2 should basically be a "skim" cut to get the cleanest finish.

Notice no ruler/tape measure is needed to set the bit this way. Typical for router setups. Sometimes bit height is set by measurements (like setting how high the bit pokes up from the tabletop when making a dado or rabbet cut) but most of the time fences and bit heights are set based on aligning key points (bit edge, bearings, etc) with a straight edge to the table and/or fence.

mpc

[mpc]

Do you have an "edge guide" attachment for your router? Most routers have an accessory that is basically an add-on fence attached to the router via two metal rods. These add-on fences often resemble the "mouse hole" table fence and work the same way. With a little practice, such a fence could make both sides of your cut (with or without a bearing guided bit) since the fence can ride on the rounded-over face unlike the bearing.

If you don't already have this... I'd spend the time & money making a router table instead of buying an edge guide. Probably easier & cheaper in the long run. I hardly ever use the edge guide for my router... and then only on pieces waaaaayyy to big to handle on a router table. In fact, I don't think I've yet opened the plastic wrapping for the edge guide of my newer router.

mpc

[LCHIEN]

MOst dangerous setup!

SteveG wrote "
Yes...as I'm picturing this, if I want my 3/4" thick stock to end up 12" wide (measured from the back "flat edge" of the board to the outermost point of the curved edge on the front of the board), then I'd set my router/table so that the bit is set to a depth such that the rounded portion of the bit is flush with the tabletop. Then, I would set my fence 11 5/8" from the "cutting tip" of the blade that is nearest the fence (which would put the "cove" portion of the blade 12" from the fence. Then, running the board through, flipping it, and running it through again would theoretically give me a perfect edge on the "long" side of the board."

MPC commented on it and I did not catch it first toime but this is a very dangerous setup. Never run the work between the fence and bit, it will grab the work, pinch it between the fence and router running at 23000 RPM and shoot that sucker out like a spear.

You can only do a bit separated from the fence for grooving where the bit is fully into the workpiece so that the pulling and pushing loads are balanced. Otherwise the bit has to be partly buried in the fence. Never have the wood fully between fence and BiT!

The cutting edge of a bit should always be rotating into the oncoming wood feed. Never have the bit so that it will grab and pull the wood forward making it uncontrollable.

This is so important a concept I'm ending the post here.

[steveg]

OK, guys, I got it. Make sense. The way I laid out my thoughts was the wrong way to do it; I was picturing doing this on my saw table, but apparently I need to use my router table.

This is essentially the table I have.

http://www.sears.com/shc/s/p_10153_12605_00926460000P

Not sure if this has a "mouse hole fence" or not, as I don't know what that is. But, I think I can accomplish what you are describing, mpc, using this fence (and some type of supports beyond the table, at the height of the table, to support the 8' long piece. Anyway, I understand what you (and Loring) have been explaining, about multiple cuts, taking a little off at a time, etc.

Yes, I need to do the sides of the tread as well, not just the front. This will probably be much more difficult, using a table/fence. It will be hard to "crosscut" (for lack of a better word) the narrow sides of an 8' long 1x12...this is part of why my original thought was to hand-hold the router, instead of trying to do this on a table. I'm not sure if I have an "edge guide," or not, need to check the stuff my dad gave me with the router, but I don't think I do.

I will come back and re-read this whole thread before I make the tread, to make sure I catch all the important points. BUT -- I understand the point of not "trapping" the wood now, similar to how you would not use the SMT with the rip fence (unless using the wood block idea clamped to the rip fence). This all makes sense -- I understand.

Loring -- thanks for the advice on the 15-piece bit set. I think that might be a good option that I plan to look at...

Steve

[LCHIEN]

that's a small table.
If you don't feel comfortable supporting the wood (and it has to be precisely supported to keep it absolutely flat on the table or the routes will not be smooth and uninterrupted) then the other option is to hand hold the router with the wood well clamped (and clamps out of the way of the router. This means then you will need to hold the router steady with the 6" or so diameter baseplate held firmly and flat on the wood while moving the router with half the baseplate hanging off the side. Something that can be done with practice. I always find it useful to make a dry run with the router unplugged to make sure my clamps and nearby stuff doesn't get in the way when I run a long thing thru it. DAMHIKT

For either table or handheld you can do this cut with a guide (or fence) or just using the bearing. Me, I'd just use the bearing for a guide.

Buy some cheap white pine like a 6 x 1 and practice the cuts on it before you do your oak. Like I said, routering is a lot about getting the feel for the tool and cut.

Also remember the feed directions all change when routing with a table or handheld because the effective rotation direction changes with the router upside down. With a board clamped and the edge you want to route facing you, you need to move the router left to right, handheld. I did this recently on a 12-foot 1x12 clamped to two sawhorses on my patio. No room to swing it in my shop on my router table. On a table, with the wood between you and the bit, you want to feed from right to left.

Like someone said, if routing three sides of your planks, do the short end cross-grain cuts first. You will almost always get a chipout breaking off with the grain on the exit side. Usually the chipout is smaller than the size of the roundover you are making so it'll all be cut off when routing the long side with the grain. Very careful feathering of the cut, down to almost nothing will help alleviate it, but its almost unavoidable unless you have a backup piece of wood. If you practice as I suggested, you'll probably see what I'm talking about.

One final note about the router bit sets: The economics may change if the user has a single speed, 1/4" only router (sounds like anyone you know?) and finds he may want to change to a better router after doing some work. If he buys a 1/4" set to fit his original router then he is stuck with a bunch of 1/4" shank bits when he really wants half-inch shank bits... just warning. I only own four routers including a 70's era single speed 1/4" craftsman router and a survey I did here some years back showed the forum members with routers have an average of 3.5 routers. So upgrading routers is a surprisingly common thing.