Gazzalodi

Router - PC 892
Speed - 10000 & ~13000 RPM
Bit - Bosch 84703MC 14deg dovetail (1/4 collet)
Table - Bosch RA1180
Stock - The best 3/4" pine Lowe's has to offer... or, the only wood in the store.
Depth of cut - 1/4"

This is my first router project since highschool (25 years ago). I have started making test cuts in preparation for this project.

When making a dado cut for shelving I am seeing 'fraying' of the wood along the edge of the cut. This is only happening when I cut the slots. Cuts for the dovetails on the shelves themselves are clean and smooth. The fraying is consistant along the entire length of the cut. After a couple of cuts at 10k rpm I increased the speed to around 13k but the results were the same.

The wood that is not completely removed is easy enough to clear off with my fingers. But I would prefer to be making nice clean cuts if possible.

I have included some photos of the router table setup, the frayed dado, and a joined test.

My questions are:
A - Am I using the router incorrectly? I don't think I am. I have seen this done numerous times so I believe it is within the capacity of a router to make this cut. The case for the dovetail bit even shows a dado cut. I recall making these cuts back in the olden days, but not with a dovetail bit.

B - Do I need to be cutting deeper for the groove? I just eyeballed it.

C - Am I using the wrong speed for the wood stock? Should I be going even faster with pine?

D - Is this just a characteristic of pine? Would a harder wood provide a smoother cut?

Any advice would be greatly appreciated.

Thanks,
Dave

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reible

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bobj3

Dave
Just my 2 cents.
I know ED said that it was a bit to deep but I always set it for 5/16" deep but it looks like you are using a dull bit at low speed.

Pine is a pain when the stock is a bit green.(not dry)
You may want to try a New Sharp bit.

Bj

reible

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Sometimes you get, and sometimes you get got.

Mike

Dave, ever make bread dough? When the dough is too wet it sticks and pulls when you try and cut it. When it is dry enough it cuts cleanly. Wood works much the same way. Pine is full of moisture and resins, both things that encourage tear out. In a perfect world we would all have wood that is nicely aged and naturally dry enough to get excellent results every time. In the real world there are steps you can take to ensure better results. Here are some general ideas that should help: Make sure your bit is clean and sharp; remove any resin build up with a solvent such as mineral spirits; examine the cutting edge for nicks or dull spots. Run a small bit like this at top speed using a steady motion as you pass the wood over the cutter. Try Ed's idea of making a straight cut first to remove the bulk of the wood, then follow up with your dovetail bit.(This is the same as making a rabbit cut in multiple passes so no more than 1/4" is removed at a time.) To reduce tear out use a backer board. This is just a piece of scrap used to push your wood across the cutter. It gives support so the wood is less likely to chunk away. Give your wood a chance to get used to your shop before working with it; a couple weeks is a reasonable rule of thumb. Remember that no matter how careful you are, there is always that piece of wood lurking out there ready to twist itself out of shape when you show it your cutting tools.

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Mike

del schisler

i made a couple wood projects out of pine that had been inside for 16 yrs and it made a mess of every tool bit and cut that i made so much pitch in it that i am done with pine del schisler

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del schisler

bobj3

Gazzalod

Here's a tip I use all the time.

All routers and router bits have a voice ♫ ♪ ,they will tell you when they are doing the job you ask them to do.
i.e. Bits will chip at you when they have chips backing up and they need to get out,
they will also tell you when they are cutting in the stock just right.
The same is true for router motors, they will tell you that you over loading them or just working them to light or just right,it's like a new language that you need to learn.

Have a good weekend

Bj

Gazzalodi

Thanks for the info everyone.

Just to clarify. The bit is new, the photos were of the first several cuts made with it.

I increased the speed, and changed the depth. Still seeing a little fraying, but I have it to the point where I can knock it off by just running my fingers over the cut a couple of times.

Other than my pitiful table saw skills, the first book shelf is coming along nicely. I have all the dados cut for the sides, the top and bottom shelf are dovetailed. Just have to cut to size 2 more shelves (dangit) and dovetail them.

I do have another issue.

The router table I have is 18"x27" and still seems too small of a workspace to do much with. The furthest from the fence touching side of a piece of wood I can go for making a cut is 3 inches. That worked okay for the top and bottom dados, but for the 2 middle shelves I had to pull the router out of the table and do them hand held. I was looking around today for an extension table or something. Everyone I mentioned it too gave me a look like I was asking them for banana soaked in motor oil. Basically I'm wondering if anyone makes an aluminum table (like the Bosch router tables) with all the slots for fences and table saw miter gauges (I have the same issue with the table saw, the fence will only go out to 12"), that can be secured the main table. Has anyone heard of such a thing?

Thanks again,
Dave

bobj3

Hi Dave

The router table is always to small when it comes to case work or a book case.

The jig below works best for me, it will put in a dovetail, dado or rabbits.
I use a 23/32" bit for the dado most of the time (for 3/4" plywood).

It's a quick and easy jig to make and it's true, just clamp the bar down and drop on the router or push with the dovetail bit in chuck.

The clamp you can get from just about any home center like ( Home Depot ) and others the key to this one is the Alum.bar on the side of the router base it must fit in to the slot on the clamp and move free but stay true.

I also made one for my power hand saw (6" bearcat) to cut up the nasty 4' x 8' plywood that's hard for one guy to move over a table saw and keep it true.

Saw jig below
http://www.routerforums.com/27897-post17.html

Hope this helps
Bj

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Gazzalodi

Thanks Bj,

I think that's what I'll be working towards, once I get a drill press. The mortise jig looks a bit intimidating though.

Right now I was just clamping a second piece of wood on top to act as a guide. Still had some drifting issues, more with the handheld saw than with the router though. I do think I need to knock out a few more bookshelves for the family first though. I was starting to get nervous looks from the wife because all the material I was buying for the bookshelf project was to expand the workshop and not actually to make the bookshelves.

Thanks again for the example.

Dave