Angle Cutting Router Jig????

[needsmorecowbel]

Hey guys I'm pretty new to router techniques but what would be the best way of accurately cutting a rectangular prism into a trapezoidal prism then accurately duplicating this with a router? I do not own a bandsaw and the table saw I have is an old Makita that lives on an old triton workbench that I don't exactly trust for precision cutting so I'd rather use a router to achieve the angles. The angle I am looking to achieve is 6 degrees (30 trapezoidal prisms needed glued together to make a "circle" Tricontagon). It is all in an attempt to make a Stave Snare Drum from spare Timber I have lying around (mainly blackwood and maple). There are some damn cool videos on you tube of how to make them with bandsaws and table saws but the jigs are never really in focus for very long.

[jeffhigh]

I made about Half a dozen stave drum shells a few years back.
I used a guide that I could clamp to the stave and run a handheld circular saw along.
It worked but I would not recommend it
Any table saw even the triton should be better
I would not attempt to shape short lengths like that though, start with long sections, cut the tapers , then do the cross cuts into the short lengths.
One technique I found handy when gluing was to lay the staves side by side with the inside down Run a couple of lengths of tape along it with a bit of overhang
Flip the taped up assembly over, add glue to the open joints, roll up and secure with the tape and then clamp with a couple of band clamps or rope loops twisted with a stick.

[needsmorecowbel]

Did you make a whole kit out of it? Yeah I can imagine that wasn't the most fun way of doing it. Good call with the longer lengths!

[Kim]

Moved this topic into the main build forum for general discussion to keep the Gallery forum clear for displaying finished instruments.

Cheers

Kim

[jeffhigh]

I made a set of African style bass drums/Toms Known as dununba, sangba, kenkeni from largest to smallest plus a couple of tapered ashiko drums
If I were using a tablesaw now I would probably use a sled to clamp the stave to while running it though.

[needsmorecowbel]

Sorry Kim the gallery is for some reason higher up in my web browser bar.

[needsmorecowbel]

I decided to only use the table saw to rip the timber (in this case Tassie Oak) got 68 staves out of it. 6 degrees is such a minimal angle on the Staves that maybe i could make a mini mitre box and use a fretsaw. I tried with a test piece to rip the angle but as you say you need some kind of sled to give it more surface area/ contact with the saw fence otherwise it just goes all over the place.

[jeffhigh]

perhaps an angled shooting board and plane

[Allen]

Jeff beat me to it. I'd be going for the shooting board option.

We've got an old high school tech teacher as a member of the woodworkers guild. He's right into multi piece laminated turning and uses a combination of saw techniques to get the parts close then shooting board to get the parts spot on.

[Kim]

perhaps an angled shooting board and plane

That's what I used to make a dome top chest quite a few years ago.

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Cheers

Kim

[needsmorecowbel]

Ok so in theory it would look something like this Jeff/ Kim?



The purple parts being the fences to ensure that the staves are the same (stave registration)

The Idea being that once one angle of the rectangle has been cut the "sacrificial piece" can be flipped and used as a fence (3rd diagram). The only real issue i can see with this idea would be that it may require some form of clamping of the workpiece. Alternatively could use an inverted router by using the bearing bit along the side of the shooting board using the same idea.

That's a ripper of a chest! Is it Sheoak or Silky Oak? or No Oak?

[jeffhigh]

Yes that's the concept, with a baseboard for the plane to run on
If you run the well adjusted plane alomg the side a couple of times first it will cut off an area to the depth of blade exposure and then run on the narrow secion left. Then you set your fence to bring the workpiece to this position

[Kim]

That's a ripper of a chest! Is it Sheoak or Silky Oak? or No Oak?

Thanks..The chest is WA Sheoak, the draw bore pins are Tassi oak...It represents one of my first (and last) ventures into electricity free projects...The only machine used was an old Stanley hand drill....Thank goodness the lights came on and I woke up to myself In my defence I had just come from a number of years in building and stair construction and had had my fill of the sound of both static and hand powertools....still don't like the sound of hand powertools that much, but the sound of a good cast iron machine whirring away can be music to the ears.

Cheers

Kim

[needsmorecowbel]

15 staves down 45 to go haha

[Kamusur]

Cowbell surely there is somewhere here on ANZLF to hide a few of those build photos.

Steve

[needsmorecowbel]

hahah but my jigs look like a festering pile of manure compared to the jigs of say forum members like charangohabsburg. I like to take film of the jigs using silver nitrate coated film for easy burning!

[charangohabsburg]

hahah but my jigs look like a festering pile of manure compared to the jigs of say forum members like charangohabsburg. [...]

Oh come on, show it off please. I'd like to learn how to do things the quick and easy way round!
I'm following this thread with interest since you started it.

[Kamusur]

Cowbell don't worry I'm a good advertisement for how not to myself but,,, Marcus is right we're waiting lol.

Steve

[needsmorecowbel]

Here goes then:
At the timber yard i found a really nicely figured board of tassie oak for 15 bucks and there was enough for 68 staves or 2 14 inch snare drums if the curl of the wood was not troublesome. Figured this would be the best way to test the jig. There are so far 6 pieces that were just shocking to carve so they have been put aside. The others were like butter with the low angle block plane. Note: Really need a good pair of vernier calipers for this. So chrissy present might be one of those.




At the completion of "rough" cutting to get a rough idea if the 15 staves would make up half a circle I realise that the angle is fairly rough and the staves are too wide. Around 2.48 mm has to come off the staves widthways and the calculations would suggest the angle is not 6 degrees but 6.07 meaning over the 15 blocks 1 am 2.1 degrees out and over the 30 blocks 4.2 degrees out.

[needsmorecowbel]

[needsmorecowbel]

Just ordered one of these: http://www.engineering-tools.com.au/cat ... _1.htm#834... so i can really begin to make less of a hack attempt at it by fine tune the roughly cut staves and definitely make a more accurate jig. Am thinking for a future build a plain Blackwood/Maple inner core with a highly figuredblackwood veneer (maple at 13mm, Blackwood at 10-11 mm). Got some Spittle Black Heart Sass that might make an appearance.

This guy makes some lovely drums

http://www.zenzian.com/products/snares

I'd seriously hate to think how much it cost him for a board of tiger myrtle an inch thick by 160-180 wide by 1300 long.

[charangohabsburg]

That looks pretty good to me (I doubt I would get that close at a first atempt, I have never tried such a thing).

Just ordered one of these: http://www.engineering-tools.com.au/cat ... _1.htm#834... so i can really begin to make less of a hack attempt at it by fine tune the roughly cut staves and definitely make a more accurate jig.

I think that's a nice and really useful gadget at a very reasonable price. But figure, you will most probably not get you rid of this tiny angle aberration just because of using a precision digital angle measuring device:

[...] and the calculations would suggest the angle is not 6 degrees but 6.07 meaning over the 15 blocks 1 am 2.1 degrees out and over the 30 blocks 4.2 degrees out. [...]

That's a 0.07° error vs. 0.1° measuring precision.

In any case (with or without precision calipers etc.), I think that "dialing in" the jig will be the fastest way to end up with good result (supporting the jig at it's whole base will make dialing in easier), and once you have the jig spot on, the next set of staves will be just a breeeze to make - at least for you. I certainly would end up cheating with at least two or three staves, or with using softer wood to squeeze it to shape when gluing the whole thing up!

[woodrat]

Hey Stu, you dont need such high figure wood for your jigs you know! Plain works just as well

Nice pickup .... the figured stuff...

John

[auscab]

Stu ,

You asked in your opening post about router techniques, the jig you made is the basic version you could use with a router. and a table saw.
Do you have an inverted router ? a router screwed to the under side of a table top , with a fence ?
And do you have a table saw?
If you have those two tools ,and your going to do more of these drums , you could set up two jigs and pump them out.
Just the inverted router will do it but the saw would be good to rough them out

And are you smoothing off the flats inside and out ,and if you are ,
how are you going to do the inside ?

[Kamusur]

Looking good Cowbell. You'd make a good cooper what with that oak and all so better start saving those old grapes ready for next project.

Steve