Cutting Small Angles

dusty · Post by **dusty** » Mon Feb 17, 2014 7:44 pm

JPG40504 wrote: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&#176]

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.

I don't understand what you are trying to communicate here.

The SU drawings show a 3/4" top side.

If the task is to trim a 3/4 x 3/4 with 2 degree bevels and maintain the 3/4" top, it could get tricky but it could be done.

JPG · Post by **JPG** » Mon Feb 17, 2014 7:50 pm

Well cat fuzz!!!!!!!!!!!!!

Hellooooooo Planet Earth!

We(that includes myself) have been flapping about the slat bottom dimension/angle and also saying a little extra clearance at the bottom would ensure a tight joint at the top.

Fer crying out loud! The design objective is that tight joint on the top. The side bevel cut is merely to allow the top of the arc to fit. So the important thing is a 3/4" top slat dimension.

Fer example, if the end piece(D) is cut to the height given in the plans, and you take Dusty's drawing(either one) and push the arc down just over an inch, the joints will open up slightly at the bottom.

If we want really tight top and bottom joints, I need the radius of part D.

Otherwise just do what the plan says!:rolleyes:

JPG · Post by **JPG** » Mon Feb 17, 2014 8:03 pm

dusty wrote:I don't understand what you are trying to communicate here.

The SU drawings show a 3/4" top side.

If the task is to trim a 3/4 x 3/4 with 2 degree bevels and maintain the 3/4" top, it could get tricky but it could be done.

That is indeed the task! I think Farmers approach is valid, with a 3/4" top width objective.

No it ain't easy to do this accurately, but I have come to the conclusion that the bottom joint be damned and make the top joint tight and get on with life.

If the bottom joints look ugly, veneer the bottom.

I said this above, but this plan is very forgiving and the outside joints are taken care of(visually) and sufficient slop included(cutting to final width after glue up) makes absolute accuracy unnecessary.

charlese · Post by **charlese** » Mon Feb 17, 2014 8:33 pm

Thank you Dusty for showing that cutting only one side, but at 4 degrees works. It seems to me that it is simpler than sawing/milling two sides of each slat.

This one side method offers a solution with only half of the possibility of errors and safety

Also as shown in the PDF of the construction, the base of the end slats is removed, therefore the small error (2 Deg.) on the outside slats will be essentially removed.

This is a lot to say about a chest lid. The maker will do whatever he wants.

I shouldn't have written so much.

It's not my job to convince anyone of anything, just offer a solution.

BuckeyeDennis · Post by **BuckeyeDennis** » Mon Feb 17, 2014 11:00 pm

charlese wrote:Thank you Dusty for showing that cutting only one side, but at 4 degrees works. It seems to me that it is simpler than sawing/milling two sides of each slat.

This one side method offers a solution with only half of the possibility of errors and safety

Also as shown in the PDF of the construction, the base of the end slats is removed, therefore the small error (2 Deg.) on the outside slats will be essentially removed.

This is a lot to say about a chest lid. The maker will do whatever he wants.

I shouldn't have written so much. It's not my job to convince anyone of anything, just offer a solution.

I'm with you on this one, Chuck. If the facets are going to be sanded smooth anyway, the tiny difference in the height of the glue-up sides is immaterial.

But now I'm curious. If the 2 degree angle is indeed generous (presumably to make sure that the outer edge of the glue joint is tight), what is controlling the overall curvature? A jig? The endpieces of the lid? How would you clamp this beast up?

JPG · Post by **JPG** » Mon Feb 17, 2014 11:22 pm

BuckeyeDennis wrote:I'm with you on this one, Chuck. If the facets are going to be sanded smooth anyway, the tiny difference in the height of the glue-up sides is immaterial.

But now I'm curious. If the 2 degree angle is indeed generous (presumably to make sure that the outer edge of the glue joint is tight), what is controlling the overall curvature? A jig? The endpieces of the lid? How would you clamp this beast up?

" part D"]Curved Slats.PDF[/URL]
chest ht.PDF

And it seems the wide faces are 'taped' together before positioning on part D.

dusty · Post by **dusty** » Tue Feb 18, 2014 7:35 am

JPG40504 wrote:Well cat fuzz!!!!!!!!!!!!!

Hellooooooo Planet Earth!

We(that includes myself) have been flapping about the slat bottom dimension/angle and also saying a little extra clearance at the bottom would ensure a tight joint at the top.

Fer crying out loud! The design objective is that tight joint on the top. The side bevel cut is merely to allow the top of the arc to fit. So the important thing is a 3/4" top slat dimension.

Fer example, if the end piece(D) is cut to the height given in the plans, and you take Dusty's drawing(either one) and push the arc down just over an inch, the joints will open up slightly at the bottom.

If we want really tight top and bottom joints, I need the radius of part D.

Otherwise just do what the plan says!:rolleyes:

The radius of part D is 10".

But don't push the arc down! Take out all of the extra slats and all will be well. I used 24 slats because the author said he needed 24. It turns out that the arch requires only 19.

With those changes, the dimensions are close to the original plan.

[ATTACH]24120[/ATTACH]

This was another fun project that has reaffirmed that I should have paid more attention in math classes. If only teachers would have given good reasons for learning all of this stuff. I also learned, again, that assumptions are often wrong.

Ed in Tampa · Post by **Ed in Tampa** » Tue Feb 18, 2014 10:27 am

My question is why out think the plan?
If the plan called for 2 degree angle and slat that was 3/4" wide at the top and 23/32" wide at the bottom why not make them and put it together?

If upon set up you find that blade cuts away some of the 3/4" top portion when the bottom is set at 23/32' then you know the angle is wrong.

I would make a test board exactly 3/4" wide then I would mark in the bottom
1/64" on each side and lay the board on the saw. Making sure the saw would not cut the 3/4 and would hit the mark I would lock the table and fence in place and start cutting.

If that does not float your boat.

I would get out a hand plane skew the blade a 1/64 or hold the plane slightly tilted and shave a thin strip off each side. I would think one or two passes on each side would be exactly what was needed. That way you don't have to mess with hold downs, setting the table tilt, worrying how to feed the wood without cutting a finger, having something slip and mess up pieces.

In fact using the plane method you would be finished by now!:D

Then I would say to myself why was I crazy enough to post this question on the SS forum where I would get a zillion ways to do it and a math debate going?

robinson46176 · Post by **robinson46176** » Tue Feb 18, 2014 10:33 am

If you were making a bunch of these lids you could just make up a cylinder with the proper radius and saw out sections of the proper size.

You could also make one by:
1. Setting up the two ends.
2. Cutting a slat.
3. Attach it to the two ends.
4 keep repeating steps 2 and 3 until the other side is reached.
If adjustment is needed at the last slat change the design of the box underneath which you wisely have not built yet...

Yeah, now I'm just messing with you.

I can't help it, you guys are a hoot...

Some of you could make eating lunch into 3 days work.

.

BuckeyeDennis · Post by **BuckeyeDennis** » Tue Feb 18, 2014 10:38 am

Ed in Tampa wrote:My question is why out think the plan?
If the plan called for 2 degree angle and slat that was 3/4" wide at the top and 23/32" wide at the bottom why not make them and put it together?
If upon set up you find that blade cuts away some of the 3/4" top portion when the bottom is set at 23/32' then you know the angle is wrong.

I would make a test board exactly 3/4" wide then I would mark in the bottom
1/64" on each side and lay the board on the saw. Making sure the saw would not cut the 3/4 and would hit the mark I would lock the table and fence in place and start cutting.

If that does not float your boat.

I would get out a hand plane skew the blade a 1/64 or hold the plane slightly tilted and shave a thin strip off each side. I would think one or two passes on each side would be exactly what was needed. That way you don't have to mess with hold downs, setting the table tilt, worrying how to feed the wood without cutting a finger, having something slip and mess up pieces.

In fact using the plane method you would be finished by now!:D

Then I would say to myself why was I crazy enough to post this question on the SS forum where I would get a zillion ways to do it and a math debate going?

Because doing the trig only takes about ten seconds?