Dangling Angles - Help needed...!!

[Dennis Peacock]

OK....here goes......

I have been commissioned to build 5 "milk stools" for kids. I have one from the customer to go by.....the problem is that each leg of the "model" stool is at varying angles....not a single angle is the same....most are not even <b>close!!!</b>

Here are the specs...:
Stool stop is round....13" across
Stool Leg length ........12" from bottom of leg to top of round tenon.

There are cross pieces (stretchers?) that are 3/4" round as well and none of those angles are the same.

How do I figure all this up to be a <B><i>consistent</i></b> angle? I do know that the angle will be a compound angle and the angle on each of the legs vary between 5° and 11°........

Is my understanding correct by stating that the bottom of each leg should be the same as the edge of the stool top?

Not being all that great at adding up numbers that are letters and NOT numbers.......how does one go about working out the math to get this right.....? I have spent most of the day today trying to figure all this out......

Any and all help would be greatly appreciated,

Dennis - :D

[Dan Barber]

Dennis,

A fact that I always try to remember is that a 1 deg rise results in approx 0.0175" for every inch of run.

So if you have a 12" long leg fit to a 13" round top I'd expect the legs to intersect the top in a circle about 10 1/2"" in diameter. If the center of the leg bottom was to line up to the imaginary line projected from the edge of the top to the floor, that would mean the 12" long leg would be angled in by 1 1/4" from vertical.

To make things simple, I try to imagine a problem like this in it's simplest form. So in my mind I would lay the stool on it's side. This would give me a mental picture of the leg rising 1 1/4" from the point it's bottom center intersected the floor to the point it's top center intersected the stool top - does this make any sense :confused:

1 1/4" (the rise) divided by 12 (the run) would equal 0.104167" of rise per inch.

Divide 0.104167 by 0.0175 and the result is 5.9524 or about 6 degrees.

This is a rough calculation Dennis. I just drew this up in Cad and the actual angle for the dimension I mention is 5.94686305 - as you can see it's a very close approximation. Any further info you need, give me a shout.

Dan

[Don Henthorn Smithville, TX]

As I said in my reply on WC I build lots of stools. I make the seats of my stools 14 1/2 " to 15" in diameter and dish them about 5/8" to make them fit today's big bottoms. Milking stools are three legged so they will not rock on uneven surfaces. However the smaller the footprint of the legs the easier it is to knock the stool over. At twelve inches high I would want the legs to splay out maybe an inch beyond the seat. I make a jig for my drill press so that the seat is held at the same angle for drilling the seat hole for each leg. Each of the three stretchers will be at a different height from the floor so you don't weaken a leg by drilling two holes at the same height. I Make my stretchers from one inch stock. and give each a pleasing shape on the lathe. I mark the legs on the inside for the stretcher positions, stretch a piece of wood from leg to leg and measure the angle of the stretcher to the leg with a sliding bevel and set the drill press table to that angle. Then I use a V-block centered under the bit to put the leg in and drill a one inch hole 1/4" deep. The I change bits and bore a 7/16" hole another 3/4" deep. The stretchers have a 7/16" tenon on the ends and are cut long enough that they can go into the one inch hole the full 1/4". The process does take some careful fitting as you go along because when you put it together everything assembles at the same time, so that when everything is driven home it is locked together and no way is it ever coming apart. Hope this helps.

[Dennis Peacock]

Dan Barber and Don Henthorn......

Many thanks for you guidance and assistance. I may be making more out of this than necessary......but I can't afford to keep screwing up good material...PLUS....I am having to figure out how to turn the legs the same for all 4 legs.....I beginner in turning I am.....being able to repeat a pattern 4 times and have them look the same is another story. So-o-o-o-o-o-o........Here is what I did:

I figured out how to build a router jig for my lathe....it sits on the bed of the lathe and I will simply clamp it secure to the ways. I have a rigid flat platform on top of that with a 1/2" slot cut the length of the legs plus a little. I will be using a PC690 router with a 1/2" guide bushing and a 3/8" 2-flute router bit and will spin the lathe slow and run the router down the leg.

I haven't tried this yet and am not really sure just how "safe" this will be but I <i>have to do something to make this turning legs more consistent!!</i>

How long have I worked on copying this little stool? About 4 days now......and I have to make <b>FIVE</b> of thse little things!!!!

I will give your guidance some practice and will let you know how I fair with the lathe jig and the dangling angles of the legs.

Thanks Again for coming to the rescue,
Dennis - :D

[David Rose]

Dennis, if you have, you will remember that the carriage carries the cutter making for consistent straight or tapered cuts. I think it would be simple to build a carriage of wood that would slide on the ways of the bed. With a rigid block attached to that you could simply wedge a cutting tool in the block where you wanted to cut. Then manually slide the whole affair slowly from one end to the other.

If this is dangerous or problematic someone please correct me. My experience is strictly with engine lathes.

David

[Bob Oswin]

[QUOTE]Originally posted by Dennis Peacock
[B]Dan Barber and Don Henthorn......


I figured out how to build a router jig for my lathe....it sits on the bed of the lathe and I will simply clamp it secure to the ways. I have a rigid flat platform on top of that with a 1/2" slot cut the length of the legs plus a little. I will be using a PC690 router with a 1/2" guide bushing and a 3/8" 2-flute router bit and will spin the lathe slow and run the router down the leg.

I haven't tried this yet and am not really sure just how "safe" this will be but I <i>have to do something to make this turning legs more consistent!!</i>

things!!!!


Well you are are on the right track but I doubt that your results will be what you need.
The router bits will not allow for much of a curve in your stock.

You can pick up a Rand duplicator on E-bay that mounts on your ways in a matter of a few seconds that will really takes the bite out of duplicating a bunch of parts.
Just cut the first one out by eye and use it as your pattern for the rest.
It's only a $99.00 duplicator but it really works well.
Purist remarks accepted here that practice is needed to make your self a "turner" but frustration can put a damper on folks just learning.

Cheers
Bob
:D