using a router to cut slots

[lum747]

i have a piece if walnut 2and 1/2 " x 3/4x 5' long and i need to cut a slot every 3" 1/4" deep about 2" , and my question is how can i cut a streight slot with my router, as i don't think it could be done freehand without some sort of guide, and seeing as how my board is only 2 and 1/2 " wide that may cause a problem
thanks, lum747

[cabinetman]

i have a piece if walnut 2and 1/2 " x 3/4x 5' long and i need to cut a slot every 3" 1/4" deep about 2" , and my question is how can i cut a streight slot with my router, as i don't think it could be done freehand without some sort of guide, and seeing as how my board is only 2 and 1/2 " wide that may cause a problem
thanks, lum747

You could make a simple jig from ¾" anything. Basically it's a guide that holds your walnut, and has a cross guide for the router base to run against it. The jig has ¾" along both sides of your Walnut, wide enough to support the base. The cross guide runs across all three sections.

Set up stops at the top and bottom, so the bit starts and stops ¼" from the long edges. Make a mark from your first cut to show how far you have to push the piece for the next cut. If you don't have a plunge router, you can tip it in near the start of the slot, and run the slot, and back it up to the start.

.

[LCHIEN]

i have a piece if walnut 2and 1/2 " x 3/4x 5' long and i need to cut a slot every 3" 1/4" deep about 2" , and my question is how can i cut a streight slot with my router, as i don't think it could be done freehand without some sort of guide, and seeing as how my board is only 2 and 1/2 " wide that may cause a problem
thanks, lum747

first of all lets see if I understand your description:
Cut a series of slots in a 5-foot long x 2-1/2" wide x 3/4" thick board
You did not specify but I presume the Slots to be in the long direction and centered in the 2-1/2" face???
Slot spacing 3"
Slot length 2"
Slot depth 1/4"
slot width - you did not specify. I presume something like 1/4"

the solution for such as situation would be to use a 1/4" spiral upcut carbide bit in a table mounted router with a fence.

Anytime you have a series of evenly spaced items I look to an indexing jig.

I would cut the first slot the right length by using the fence, setting the bit at the center of the 2-1/2 distance, and dropping the wood onto the spinning bit against the fence and moving a mark on the wood between two points on the fence marked 2" apart. Keep the wood firmly tot he fence using push blocks and maybe a featherboard - this will make your short slot straight. With the bit 1/4" high you could make a single pass... don't push too hard but fast enough to prevent burning. 1/8" is the preferred depth for 1/4" bit, but 1/4" is doable, I think for this cut.

Then make a jig using a 6' 1x4 and a 6' 1x2. Put the 1x2 butted to the edge of the 1x4 to make a shallow "L" the 1x2 will become your new fence.
Use a dowel center in the slot of the workpiece to locate a hole in the top of the 1x4 with the workpiece against the (1x2) fence and the hole 3 feet from either end. Drill the hole to accomodate a 1/4" dowel sticking about 1/8" proud of the 1x4. Drill a 1/2" hole 3 inches to the right of the dowel.

place the jig on the router table, fence to the back, and 1/2" hole centered over the bit. Raise the bit so it is 1/8" above the face of the jig. Clamp the jig to the router table with the workpiece on top and the 2" slot spanning the router bit (you probably need to remove the dowel for this). THis is important to get it straight. Clamps should be placed on the front of the jig so you can slide the workpiece on the jig. replace the dowel.

You are ready to cut add'l slots... Drop the slot just cut over the dowel and the spinning bit will cut into the workpiece. Sloide the workpiece back and forth as permitted by thte slot and the dowel - this will cut a perfect copy of the original slot length. Lif the piece up and place the just cut slot over the dowl and drop the workpice on the spinning bit again. This will cut the third slot as you go back and forth. Repeat for the lenght of the workpiee. Flip the workpiece end for end and repeat if the original slot was in the center, not the end.

Now raise the bit to 1/4" Repeat the entire process to deepen the slot to 1/4"

The key part is getting the router bit and the dowel pin the right distance from the fence. Drilling a hole through you original slot might be one way to help you do this, if a single through hole won't bother you. There are other ways... Among them you can cut the original slot after the jig is in place. That way the router will be in the same width for all the slots. I'd use a 1/4" dowel center to set the dowel hole form the slot. If you don't have a dwel center, they are quite useful for registration and inexpensive.

[jussi]

Router table or edge guide. If you have 2 edge guides you could them on either side of the router and cradle the stock. I like using downspiral bits for dados. They push the wood fibers down and leave a cleaner cut. Dust accumulates more but if your router has good dc it's not really a problem.

[lum747]

Thanks guys i will give that a try

[JimD]

Seems easier to use a template guide in the router base with a straight or upcut router bit and a scrap wood jig. I like to take a piece of 1/2 to 3/4 wood or plywood, rip a piece the right size for the template guide I want to use, maybe 3/8 or 7/16 in this case (OD) out of the center and then cut it to length to create a slot a little longer than the slot you want to create in the workpiece. For a 3/8 template guide and a 1/4 router bit, the slot in the jig needs to be 1/8 longer than the slot in the workpiece. Then I glue up the 4 pieces of my little jig and when the glue is dry, I am ready to repeatedly cut slots in my workpiece. You can put a fence on it to help align with the center of the workpiece. Almost takes more time to describe than do. Sometimes I put the jig back together with screws so I don't have to wait for the glue to dry. The same sort of jig is great for routing for hinges and lots of other applications (including slot mortises).

Jim