Shopsmith Forums

Ed can you provide any more info on using the router bits?

I think the best way is to cut them is your idea of Tilting table the 2 degrees then since the bottom of the board narrow part of camfer is 23/32 move fence 23/32 from the blade on the left side.
Then using finger hold downs place one before the blade and one after to hold the board tight against the fence.
Then using another hold down place it on the fence to hold the wood tight against the table.

Then set your first piece on the table and using another piece guide it through the cut. Then take the piece and reverse it so front is now in back making sure the face that was on the table is still on the table and push it through again. When you finish you should have a piece of wood that looks just like the picture. 3/4' wide at top and 23/32 wide at bottom. If not then the 2 degree angle is wrong and you need to refigure the angle.

May work I am going to give it a try. My only thought is that once the first cut is made and if it is down at the 23/32 the second cut will not come out right since the slat is now narrow from this first cut. What do you think? i will give it a try

dusty wrote:His plan does say 23/32" but a 2° bevel on each side with a 3/4" top surface results in 47/64" bottom surface.

Big deal! A 1/64" difference (on each piece). What's 1/64" here and there.

Would it be like farmer said and make the seam on the top edge tight while having a little wiggle room on the bottom?

dusty wrote:His plan does say 23/32" but a 2° bevel on each side with a 3/4" top surface results in 47/64" bottom surface.

Big deal! A 1/64" difference (on each piece). What's 1/64" here and there.

Okay my swimming head is confused now. Wood ya knot want to cut off 23/64" off each side? Which wood be a result of 46/64(23/32)" bottom? I think I'm with Farmer in what am I missing.

[quote="bear1050"]Ed can you provide any more info on using the router bits?/QUOTE]


The bits are used with a router table...there is one bit for the bead and another for the cove. One long edge of each strip gets a cove and the other long edge of each strip gets a bead. the result is a sort of ball and socket joint which allows a bit of movement while still remaining tightly closed on both sides. I have attached an illustration from the Guillemot Kayaks website that shows the comparison between strips that are left square, strips that are beveled and strips that are shaped into bead and cove. The strips shown are only 1/4" thick, but cutters for thicker strips are available.

If for some reason I wanted to build the lid we have been talking about and did not want to go the bead and cove route, I think I would need to create a full-scale drawing of a cross-section of the lid. As has been discussed, the specified 2 degree angle will remove a bit more than 1/64, which will alter the width and height of the lid. I assume a little variation in the height would not be an issue, but the width of the lid has to match the box. I would start with the width as my fixed 'given", draw in the rest of the lid and then use a bevel gage to take the angle right off the drawing and use the bevel to set the table tilt.

dusty wrote:His plan does say 23/32" but a 2&#176](on each piece[/SIZE]). What's 1/64" here and there.

x 24 = 3/8":eek:

I will attempt to explain from whence I have been coming with my earlier 'comments'.

First the dimensions of the trapezoid. With a top width of 3/4" and a height of 3/4" and a bottom width of 23/32, the amount removed from each side at the bottom is 1/64". From that I say the fence need be 47/64 from the blade for both passes(saw or disk). The tilt is set so that exactly 0 material is removed from the sides at the top.

Assuming the dimensions given are correct, the angle of the bevel is not 2°, but 1.19°

I am not very good with chords, but I notice Dusty is doing quite well with sketchup(wonder what radius he is using) but his heights are over an inch too high. Wonder what using 1.2° rather than 2° would yield.

Arch height b= 2 3/16"
Arch width(chord) = 12 1/2"

Arch radius = ???????????????


P.S. his arch width (span)(chord) is too long also?

So how is the curve for part D drawn for the curved edge?

I think that small a cut could be done on the shopsmith with a router bit, a tilted table and a router/shaper fence or a temperary wood fence attached to the rip fence. . You might need to have a few extra pieces of wood to fine tune the angle; but should be pretty easy.

Just my 2 cents worth.

Jack

beeg wrote:Okay my swimming head is confused now. Wood ya knot want to cut off 23/64" off each side? Which wood be a result of 46/64(23/32)" bottom? I think I'm with Farmer in what am I missing.

Geez Beeg you are making MY head spin!

Starting with 3/4"(24/32) stock, if you remove 23/32 off one side, you are left with 1/32. Let's assume you meant to set the fence at 23/32(as EIT stated) you would be taking 1/32 off the bottom. Flip the workpiece and you remove 1/32" from the other side. Thus you have removed 1/32 + 1/32 = 1/16" from the bottom making the new width 11/16.

Setting the fence to 47/64 takes 1/64 off each side = 1/32 yields 24/32 - 1/32 = 23/32.

What Farmer was 'missing' is why all the complicated gyrations to cut a simple equal sided trapezoid.

But, if you take a 2 degree bevel off only one side of a 3/4 x 3/4 what do you have?

[ATTACH]24119[/ATTACH]

Which one is correct? One side beveled or two sides beveled???

While y'all are flipping the bottom width setting around in yer noggin, remember the top needs to be 3/4"(angle dependent). I do not think '2°' will get that.

Need that part D arc radius.

FWIW this plan does allow for some slop since the final span is sawn to size after it is glued up.

dusty wrote:But, if you take a 2 degree bevel off only one side of a 3/4 x 3/4 what do you have?

[ATTACH]24119[/ATTACH]

Which one is correct? One side beveled or two sides beveled???

Try two sides beveled at 1.19°.