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cutting a hexagon

jack1939's picture

I am going to make a candle stand, to start I have a 3 inch square by 24 inch long piece of wood I will use to turn the center of the candle stand. Before I start turning I want to change the piece from a 4 sided square to a hexagon with 6 sides. How do I do this on my table saw? In addition I also want to taper it from 3 inches to 1 and 1/2 inches. I know each side should be 30 degrees but when I lay it out on the 3 inch end I do not end up with 6 equal size lines.


Thank you, 

DWRead's picture

(post #81700, reply #1 of 26)

Where is the 30-degree angle located?

DonaldCBrown's picture

(post #81700, reply #2 of 26)

Is the hexagon in the attachment what we're talking about?


 

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jack1939's picture

(post #81700, reply #12 of 26)

There should not be an attachment. looking at the end of the board would the hexagon shape. I want to change  a 3 inch square by 24 inch long turning blank into a hexagon shaped cylinder. I am trying to copy a candle stand that has 6 inches of hexagon area at the bottom where the 3 legs attach and is turned above that area up to 3 inches from the top where it returnes to a hexagon shape again. The hexagon area at the bottom is close to 3 inches wide and tapers to approximatey 1 and 1/2 inches wide at the top.


Thanks for you interest   

Dennis02's picture

(post #81700, reply #17 of 26)

Jake -

As I noted in my initial response, which dimension do you want to end up at 3"? The hexagon can *only* be 3" across opposite corners. This would also produce a 3" cylinder where it starts at the bottom. If you want the hexagon to be 3" across opposite *sides* you will have to start with a bigger piece of stock.

If the top hexagon is smaller than the bottom one, I should think that for design purposes you'd want the sides to be square to the base rather than tapered. For that, I'd suggest milling the first larger hexagon leaving the opposite end square for the time being. Turn the tapered cylinder up to the point where the smaller hexagon starts. Then carefully, using a shooting board, mill the second hexagon by hand with a hand plane.


...........

Dennis in Bellevue WA

woodnut@anatechsys.com

........... From Beautiful Skagit Co. Wa. Dennis
Dennis02's picture

(post #81700, reply #26 of 26)

Here's a little follow up on the issue of cutting a hexagon.

The project: a turned carver's mallet with six sided granadillo(sp) laminated face on the head with an ash handle.

The pieces for the head were all milled to fit into a hexagon and were about 3/4" thick. I measured the distance across the inside of the resulting hexagonal opening to find the distance across opposite sides of the handle which had to be milled into a hexagon to slip inside for gluing. This established one dimension for the rough handle. Measured across opposite corners of the hex opening to get the other dimension.

Set up and tested the jointer for a 30 degree cut. On the *Long* or *Wide* edge of the handle piece, I marked the exact midpoint of the edge. This is where the vertex of the hex will occur along that side and marked the cuts with a protractor device on the steel try square.

At the jointer, I "sneaked up" on the rough layout cuts with the head assembly, held together with big rubber bands, near for trial fitting. The jointer set to take off just a feather cut once I got pretty near there, it was a matter of .... well, trial fit-up. But got it about as perfect as I could expect.

I'll post a shot of the mallet in the gallery once done.




...........

Dennis in Bellevue WA

woodnut@anatechsys.com

........... From Beautiful Skagit Co. Wa. Dennis
jack1939's picture

(post #81700, reply #13 of 26)

I am sorry I did not understand your question before I sent my first responds. Your attachment is correct.

mrbird90's picture

(post #81700, reply #3 of 26)

If you want to use the table saw set the blade angle to 30 degrees. For a right tilt blade the fence should be on the left hand side. A taper jig should work to get the taper you want. 

sainbern's picture

(post #81700, reply #4 of 26)

Hi Jake;


 


Cutting a hexagon is a easy as drawing a circle...... Draw a circle with a radius that equals the lenght of one of the six sides you want. Without changing the compass setting, walk it along the circumference of the circle you just draw, pay attention and you will get an equal six sided figure. Here it is. If you split the dimension of one side of you turning square and use that point as starting point you will get a heaxagon that is parrallel to the sides of your square.


As for the taper, mark both end of your square according to the sizes you want, join the two end together with a pencil line, that will give you the cutting angle you need. A taper jig should help you out on a table saw, better yet use a band saw if yoy have.


Sainbern

Dennis02's picture

(post #81700, reply #5 of 26)

Jake -

You can't mill a hexagon from a square piece of stock and end up with parallel sides of the hexagon at the same dimension as the square. The maximum dimension of the hexagon will be from opposite corners which will be the 3", assuming accurate ripping. The dimension across the flats, or parallel sides will be 2 19/32" to the nearest 1/64th". (2.59807621" to be precise to 8 decimals).

I would approach it this way:

Take a piece of scrap the exact same dimensions as your finished work piece. Rip it down to 2 19/32" (the dimension between prallel sides of the hexagon).

Set the TS to 30 degrees. Mark the test piece on the two narrow opposite sides down the exact center of the face, lengthwise. Test rip the scrap and adjust the fence so you cut rght to but not even a hair over the centerline. Invert the piece and rip the other side (not the other face) so you end up with two adjacent corners of the test piece ripped off at 60 degrees. Now turn the piece around and rip off the other two corners.

This should yield a hexagon at 3" across the corners, give or take a 64th of an inch. I'm sure you're aware that centering this up accurately is crucial to ending up with an even transition at all corners from the straight geometry to the turned portion.

It just so happens that a hexagon inscribed in a 3" circle has sides of 1 1/2".

Of the few hexogonal pieces I've built, I use a 30 degree bit in a table mounted router. The only way I found of setting a reasonably perfect 30 degree angle for my table saw was to rip a long piece both sides at 30 degree setting, chop it into 6 shorter pieces and assemble them into a closed form to test the joint gap. Any correction of the blade angle has to be divided by six since the error is multiplied by the number of joints being cut.



As for the taper ..... you've got me on that one, bud! (grin) I'll hafta sleep on it!!




...........

Dennis in Bellevue WA

woodnut@anatechsys.com

........... From Beautiful Skagit Co. Wa. Dennis
ianneuhaus's picture

(post #81700, reply #6 of 26)

Dennis


forgive me, but as I understand the situation, Jake is going to turn the stick in his lathe.  So what he's really trying to do with the hexagon is cut down on the amount of roughing out he has to do.  In this case, an approximate hexagon is more than good enough so long as he doesn't cut inside the finished circle.   My suggestion would be to taper the stick, chamfer the long edges off with a plane and then start turning.


No doubt, this will start a flurry of responses from the turners on how much preparation is required before you start turning. 


Ian

eddiefromAustralia's picture

(post #81700, reply #7 of 26)

Jake,


Are you cutting a hexagon so that the work sits true in a 3-jawed chuck, or simply to hog off excess waste?  That is to say, is this level of accuracy really needed for the work you're doing?


 


Cheers,


eddie

jack1939's picture

(post #81700, reply #16 of 26)

In this situation I am not cutting down on the amount of waste. I am trying to copy a candle stand that has 6 inches of hexagon area at the bottom where 3 legs are to be attached and is turned above that area up to 3 inches from the top where it returnes to a hexagon shape again. The hexagon area at the bottom is close to 3 inches wide or thick and tapers to approximately 1 and 1/2 inches wide or thick at the top and the length of this piece is 24 inches.


Thank you for your interest.

eddiefromAustralia's picture

(post #81700, reply #20 of 26)

Jake,


 


My very rough sketch after 19 hours on-the-go attached.  Hope that it makes sense.


 


Also attached is a procedure that I would consider.  In the light of a new day I may make some minor changes, but this is the general principle that I would attack it from.  Be guided by other's responses as well as mine, please.


I would also consider doing the turning on the 3 x 3 blank and then cutting the hexagons after.  A lot of work if it turns sour and you've spent time on the forming of the hexagon profile initially.


Hope that this helps.


 


Cheers, eddie


edit:  have allowed 26" a/c 1" offcut at each end for attaching to lathe drive spurs, screwing to jigs, etc.


 


Edited 11/6/2002 5:29:35 AM ET by eddie (aust)

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Dennis02's picture

(post #81700, reply #8 of 26)

Ian -

I didn't consider doing the roughing out issue. You may be right. We'll have to see how Jake responds. That being the case, I (personally) don't see the advantage of putting the taper on via the pre-milling operation. I'd just turn it to the desired taper. We're not talking about that much more waste removal in turning as it would take setup time and work to get it tapered on the saw. Not to mention the added safety issues involved. I consider lathe work to be amongst the safest operations in my shop. Not without its safety issues to be sure but safer than having a 10" disk edged with razor sharp points whirring about at extremely high speed! (grin)

In addition, given the small diameter of the piece (3" per side) roughing out the whole thing on the lathe would be my preference.

...........

Dennis in Bellevue WA

woodnut@anatechsys.com

........... From Beautiful Skagit Co. Wa. Dennis
DWRead's picture

(post #81700, reply #9 of 26)

If Jake intended to lathe the entire piece smooth, wouldn't he have just aimed for an octagon? It would be closer to circular and easier to figure out.

DWRead's picture

(post #81700, reply #10 of 26)

How about this: Cut 0.2" off two opposite sides. The cut off the 30-60-90 triangles that start at the midpoint of a short side and end 0.75" from the corner on a long side.

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hmthomas's picture

(post #81700, reply #11 of 26)

Come on Jake, lot's of folks are dying to help out on this one. There are alot of great suggestions on how to go about it but the group needs to know what it is you are trying to accomplish.


I recently cut the hex on the tablesaw with the blade set at 30 degrees. Experiment a bit with it to be sure that you have it set exactly at 30 or like Dennis said, it won't work.  Once you are sure of the setup the rest should be easy. 


Now, what about the taper? How are you going to handle that? Seems to me the tapering jig won't work because once you cut 3 sides the remaining 3 sides don't have a good reference side to use against the jig.


Good luck, Hugh  

jack1939's picture

(post #81700, reply #15 of 26)

In this situation I am not  cutting down on the amount of roughing out. I am trying to copy a candle stand that has 6 inches of hexagon area at the bottom where 3 legs are to be attach and is turned above that area up to 3 inches from the top where it returnes to a hexagon shape again. The hexagon area at the bottom is close to 3 inches wide or thick and tapers to approximately 1 and 1/2 inches wide or thick at the top.


Thanks for you interest.

ianneuhaus's picture

(post #81700, reply #21 of 26)

Jake


I think I understand what you're trying to achieve.  You want to make a column that is hexaganal at the top and bottom with a tapered cylinder in between.    My suggestion is:


for a rectalinear hexagonal base, ie one with no taper - cut the whole blank into a regular hexagon of the size you need for where the legs attach using one of the methods others have described.  Then cut the smaller diameter hexagon using whichever tenon cutting method you are most comfortable with.  Instead of cutting a four sided tenon centered at the end of a square post, you will cut a six sided one centered on the end of a six sided post.  If your large diameter hexagon is precisely cut and you take care, the top hexagon will also be precise.  Now place the blank in your lathe and turn the cylinderical taper.


for hexagons that taper, follow the method above but start with a longer post.  After cutting the rectalinear hexagon the full length of the post, cut tenon shoulders of the right depth at each end of the tapered hexagonal sections.  Turn the tapered cylinder.  Use a band saw to remove most of the waste from the hexagonal sections then clean them up by hand.  


Hope this helps, can you post a photo of the finished project ?


Ian

ScottInMadtown's picture

(post #81700, reply #14 of 26)

Jake,


I have two methods you could try.


Method One:  The first would be to do your layout very carefully.  Then rough with a table saw or band saw.  Finish to your layout lines with handplanes.


Method Two:  I saw in a back issue of FWW....funny how I can never recall issue numbers....a fixture that held both ends like two centers of a lathe.  That fixture had a bottom piece as long as the piece you are going to cut.  Then two short pieces that stuck up from it with a screw point on each to hold the stock in question.  That holder was then put in an angle fixture to get the taper.  To get all 6 sides you would just have to turn the blank in 60 degree increments and run it through your tablesaw with the angle fixture 6 times.


Feel free to contact me directly if you'd like further direction on my cryptic description above.


Scott A. Walterman

If at first you don't succeed....kick it!
DonaldCBrown's picture

(post #81700, reply #18 of 26)

As I understand it, you want the bottom 6"-long hexagonal part to taper and the top 3"-long part to taper at the same slope, to end up with a hexagon fitted into a 1-1/2" square at the top. That is, the bottom hexagon is 3" point to point, and the top one is 1-1/2" point to point.


A jig has been suggested and is a good idea if you intend to cut a lot of these. For a one-off, I recommend using the bandsaw. Draw the appropriate cut lines using whatever method you desire. I've attached some top and bottom dimensions; maybe that will help. Cut just outside the line. Reattach each cutoff as it occurs with packing tape or whatever is handy, and cut another face. Stick a couple of pieces of paper in the kerf to account for the width of your bandsaw blade if you really want to be finicky.


Smooth the hexagons with a scraper, plane, sandpaper, or other tool of choice. 


Then do the fun part, the turning.


 

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DWRead's picture

(post #81700, reply #19 of 26)

Does tapering take place in the hexagonal sections, or do they stay the same diameter?

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jack1939's picture

(post #81700, reply #22 of 26)

The hexagon sections taper like the one on the right in your attachment.

DWRead's picture

(post #81700, reply #23 of 26)

If you're trying for a constant slope from 3" down to 1.5" over a 24" run, that's a small angle. None of my equipment is that precise (but it is all economy stuff)!

ianneuhaus's picture

(post #81700, reply #24 of 26)

Jake


Look at Fine Wood Working Issue 156, June 2002.  In Methods of Work (P14) is a taper jig that could readily be modified to cut the tapers you require.  The modification I suggest is two V-blocks that support the piece in a way that two of the faces are absolutely vertical.  You can now taper four of the faces turning the blank onto a new edge after each cut.  The last two cuts will require that the suport blocks be relocated.  The principle I'm relying on is that the long edge of a hexagon (regular or tapered) is always parallel to the centre line of the piece.


Treating the tapered hexagons as tapered tenons at either end of the piece, as in my earlier post, will also work but requires much more hand work. 


Ian

trialnut's picture

(post #81700, reply #25 of 26)

Jake


Glue up your stock 2" longer than the finished length. Cut your hex shaped columne in whatever method suites you best. Workbench magazine issue #274 on page 32 shows how to do this easily on a table saw. Trim both ends square. If you are tapering from 3"to 1 1/2" then that is 3/4" taper per side. Divide that into an easy to work with fraction for the next step. Example 3/4 ÷ 6 = 1/8. Set your jointer for 1/8 depth of cut. Set a stop on the infeed table at the same length from the center line of the cutterhead to the stop as the finished length of hex. Fire up the jointer and set the top of the hex against the stop and lower the other end onto the outfeed table and run stock through. You should have just cut a taper from 0 to 1/8. Repeat on other five sides and repeat until you have taken 6 cuts per side. You should have a hex that is tapered from 3" at bottom to 1 1/2" at top with a 2" straight hex at the bottom that needs to be trimmed off. This may sound like a real dangerous method but is really quite safe. You have plenty of length to be able to feed stock without getting hands to close to the cutters. We use this method quite often to put draft on parts for patterns. Using this method you don't need to know the taper angle only the taper amount. It's a fast, easy and accurate way to taper stock.


Hope this helps.


Rich


 


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