small spline jig anyone?

[dusty]

Hi,

When I look at this I see a potential of not have enough blade exposure with the 6" blade and perhaps some design changes will be needed to even use an 8" blade.

Since I have given you no dimension it would be pretty hard to see the problem. The base is 3/4" as are the other parts. So the very edge of the work piece is 3/4" + the "V" notch... not looking good for the 6" blade.

Anyway stay tuned for a future post where this will be addressed.

Ed

Using 3/4" material (as you state), according to my calculations - the deepest spline you can get is 1" with a 10" blade.

[reible]

If you have been following the posts it should be clear that the design has a problem. The following sketch should show you just how big the issue is.

[ATTACH]13837[/ATTACH]

Let me try to work everyone though it. Starting on the left the green box represents the maximum cut of a 10" blade(3 1/4"). From the "V" notch the extension is 1 7/16.

From the left is the red box which shows the max. depth of cut for an 8" blade (2 1/4"). The "V" notch now shows just 7/16" of extension.

The blue is a 6" blade, as you can see it will not even complete a cut though the jig let alone provide a spline cut.

Before we run off yelling the sky is falling the second part of the this check out phase is to determine how deep we need to cut. For me I don't see using anything thicker then say 3/4" stock for a box project. However I would like the option of a through cut to support a shelf in the box (corner of box has spline exposed so a shelf can set on it or for square box legs).

So here is that information:

[ATTACH]13838[/ATTACH]

Pictured in brown is two sides of a box. The through spline is the "V" of the box. Material is 3/4". The light green box shows the depth needed to install the through spline, this would be the maximum depth ever cut. Even a 10" blade can not cut that deep so this means things have to shrink.

The dark green show the maximum height one would want to cut without the cut being seen from the inside. I backed off by 1/32" from a through cut for the measurement.

This is it for tonight. Tomorrow I hope to explore a few options. Since I don't have any 6" blades that might be removed from the requirements, but I still really want an 8" option so that will happen one way or the other.

Ed

[charlese]

I LOVE your Threads, Ed! Been following this one with interest. I have made a simple jig to make splines and have also used it to rip round objects. When starting on a new project this week - had to make a longer jig to rip longer objects. Would have had a couple Pixs here, but camera batteries dead:eek:. Will post pix ASAP. My jigs are the result of ripping a 2X4 at a 45 deg. angle through the center of the board. Then glued to a plywood base.

[JPG]

If you have been following the posts it should be clear that the design has a problem. The following sketch should show you just how big the issue is.

[ATTACH]13837[/ATTACH]

Let me try to work everyone though it. Starting on the left the green box represents the maximum cut of a 10" blade(3 1/4"). From the "V" notch the extension is 1 7/16.

From the left is the red box which shows the max. depth of cut for an 8" blade (2 1/4"). The "V" notch now shows just 7/16" of extension.

The blue is a 6" blade, as you can see it will not even complete a cut though the jig let alone provide a spline cut.

Before we run off yelling the sky is falling the second part of the this check out phase is to determine how deep we need to cut. For me I don't see using anything thicker then say 3/4" stock for a box project. However I would like the option of a through cut to support a shelf in the box (corner of box has spline exposed so a shelf can set on it or for square box legs).

So here is that information:

[ATTACH]13838[/ATTACH]

Pictured in brown is two sides of a box. The through spline is the "V" of the box. Material is 3/4". The light green box shows the depth needed to install the through spline, this would be the maximum depth ever cut. Even a 10" blade can not cut that deep so this means things have to shrink.

The dark green show the maximum height one would want to cut without the cut being seen from the inside. I backed off by 1/32" from a through cut for the measurement.

This is it for tonight. Tomorrow I hope to explore a few options. Since I don't have any 6" blades that might be removed from the requirements, but I still really want an 8" option so that will happen one way or the other.

Ed

You can gain an inch of cut depth by altering the cut/joint of the 'yellow' trough(They could be supported by wedges under the ends[or more often] attached to the white 'base').

[pennview]

Here is another example of a jig to add splines/feathers to the mitered corners of boxes.
[ATTACH]13843[/ATTACH]

The jig itself is guided by the rip fence, which you set to determine how far the spline/feather is inset from the top or bottom of the box.

It's made from a piece of 2 x 8 with wood strips attached to both sides to reinforce the jig. Simply tilt the table to 45 degrees and cut out the center section of the jig to form a trough that holds the box when cutting the spline/feather slots. Leave about 1/8" of the 2x8 at the center when cutting the trough. The scrap center section is then glued to the top of the jig to give added support for the box. Those triangles are examples of spacers used to adjust the location of the slots without have to reset the fence.

I used screws to "clamp" the sides to the 2x8, but removed them after the glue dried.

Another method would be to simply crosscut the 2 x 8 in half at a 45 degree angle and then flip over one of the pieces to form the trough for holding the box. Then cut a triangular piece or two to deepen the trough.

This jig won't cut really deep slots, but could be made to do that by adding additional layers of 2x8 and wider strips to the sides.

I knew a guy selling jewelry box, etc., that cut really deep slots in some of his boxes. They protruded into the interior of the box so that a lift-out tray could be supported.

Another point about using one of these jigs is that you want to use a saw blade with a flat top profile so that the slot has a square bottom. I have several -- one is a Freud 60 tooth, thin kerf blade (I think it was sold as a model 404, but don't know if they still sell this model). Another is a 7 1/4" blade that I picked up at Home Depot years ago called Laser.

If you can't find something appropriate, but really want something to cut square slots, Forrest with grind one of their Woodworker II blades to do the job, but they are expensive.

For really narrow slots, I've used metal-working "slitting" saw blades that you can get from Enco, MSC, Grizzly, etc.

[pennview]

Another point about cutting the slots in boxes for adding splines/feathers.

When assembling boxes with mitered corners, you can use masking or packing tape to hold the corners together while the glue dries. If you leave the tape in place while cutting the spline slots, you will prevent possible tear-out or chipping of the slots that may result when the blade exits the back of the slot.

Alternatively, you can use thin plywood or hardboard behind the box as a sacrificial backer board to prevent the chipping or tear out.

[reible]

Hi,

I haven't forgotten about this posting but due to things beyond my control I haven't been able to work on this project the last few days, and it looks like a few more before I can again.

I have been thinking about it and not liking the options I see... I really wanted the "V" portion to be a design element of the structure... not seeing a good way to keep that yet.

More when I can.

Ed

[JPG]

Hi,

I haven't forgotten about this posting but due to things beyond my control I haven't been able to work on this project the last few days, and it looks like a few more before I can again.

I have been thinking about it and not liking the options I see... I really wanted the "V" portion to be a design element of the structure... not seeing a good way to keep that yet.

More when I can.

Ed

Keep the "V" as intended, but split the base. Gain = 3/4" cut depth. The support wedges become more critical to alignment of guide bars and strength. i.e. the "V" becomes the main support stucture. The base will have a through slot in the middle anyway!

[dusty]

I was working on images while JPG posted. I think that we are on the same wavelength here. That's scarey.

I like your concept and I see the issue with limited depth of cut. Here is an image that I think may depict a solution without changing concept. I would consider making the base thinner along with imbedding the sides so that the vertex of the v groove is at surface level. This approach would gain about an inch of depth in the available cut.

I would also consider 1/2" material even for the v groove and structural braces. to further reduce weight.

[ATTACH]13867[/ATTACH]

BTW I don't care for your color choices at all.:)

[reible]

I do understand what you are saying and from day one the "V" has been the major structure. I had hoped to have the table structure to get alignment, also the reason for dual miter bars... as you said most of it is cut away anyway. The blade guard also serves as bridge and perhaps adding a backside bridge too would allow for making 45 deg "V"'s out of the front and rear to hold the main 90 deg "V". The blade guards and miter bars would then hold the jig together.

I think I have an older version of sketchup on my laptop... maybe I can just start again on this portion of the design and then catch up the design on my main computer later.

Ed

Keep the "V" as intended, but split the base. Gain = 3/4" cut depth. The support wedges become more critical to alignment of guide bars and strength. i.e. the "V" becomes the main support stucture. The base will have a through slot in the middle anyway!