Cutting small wedges for segmented vessels

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Fly-by-Night CC said:

Thanks, this is usable information. Does he use a CMS, or cut by hand? I was kinda hoping to do this over the next week, starting today.
I've been cutting with a tablesaw and homemade jig, but can't do that at this moment in time. I've been looking at plate (disc) sanders, but the one I considered fit a tablesaw arbor and the jig I had envisioned rides in the miter slot. A lathe mounted dick would be OK, but there is no way to clamp the jig reliably. Or I just haven't thought up the right method...

I'll look into it, thanks. Do ya loan out videos to strangers in GA? I promise to mail it back the next day... ;-)
Greg G.
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Greg G. wrote:

You can't get there from here.
How many segments make the 360 degree circle?
If perhaps 8, then make 7 pieces one size and use the 8th one to soak up all the tolerance errors.
It's the best you will do.
Lew
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Lew Hodgett said:

Sure you can. Just not without a table saw and a dick sander.

It depends on the design, and whether or not they have thin strips of veneer between them. I have a computer program and a special tablesaw jig to cut precise angles for these things.

Won't work - they have to be precise so that the layers line up correctly. You DO have to sand 180 segments sometimes to even them up a bit before gluing.

I hope not... ;-)
Greg G.
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Greg G. wrote:

It sounds painful!
--
Jack Novak
Buffalo, NY - USA
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no(SPAM)vasys said:

Whoops - BIG typo.
Yes, it sure does... :-) Excruciatingly so. So much so that I think I'm going to go watch TV for the next week.
Greg G.
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Umm, go back and look at the post where you were contemplating mounting one on the lathe. You got a donor in mind? =:-O

+--------------------------------------------------------------------------------+ If you're gonna be dumb, you better be tough +--------------------------------------------------------------------------------+
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Mark & Juanita said:

Must be advancing age - I can't type anymore... But you're right - same mistake - same word. Hmmm....
Or it could be this cheap-#%$ keyboard... If it turns off the "insert" key one more time... I'm sending it back to
[POT]
China.
Greg G.
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You will not be able to make them accurate enough, no matter how good your equipment. I got my incra 5000 to within a few thousanths over 18" and the accumulated error (remember, we're talking 12 segments 24x magnification of any error) still left a gap.
The solution is to come up with a way to build the rings *without* needing that kind of accuracy. For 12 segments, it's usually sufficient to build two halves leaving the ends long, then trim or sand them so that the ends are coplanar (which is easy to do accurately enough) then glue the halves together.
For more segments, trimming quarter rings might be useful. If it were me, I'd tape a printout of the segment wedges to my crosscut sled so that I can line up the segment seams on the printout to keep the segments approximately the same size. For half rings, I use a marking knife to mark the four long ones based on one of the short ones, then clamp it to the crosscut sled so that the marks line up with the edge.
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DJ Delorie said:

I built a special table saw jig for cutting them. Works fine. Kind of like a large, accurate Dubby.

That's what I do, sand the 180 degree sections before final gluing. I use a computer program to calculate the cuts.

But how do you cut them wi... Oh, never mind...
Greg G.
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I use the Incra. With the stop and the fairly rigid angle setting, it's nearly perfect - I tried doing 12x regular sized and gluing them up, but it always left a hairline opening somewhere. Truing halves gets rid of that, but the accuracy of the Incra means the segments end up all the same size.
Also, the incra happens to have that zero-clearance edge and T-slots for doing the half-ring-trimming step.

I can one up you. I *wrote* a program to do that :-) http://www.delorie.com/wood/segturn.html

Idea: Mill a larger board, say a hardwood 2x4, with a routed slot on top just wide enough for the width of your segment stock. Use it to hold the stock while you cut it in the miter saw. Or, with a slot deeper than your stock, you could clamp a straight board on top of it at the right angle and use a dovetail saw to cut a thin slot, making a custom precision miter box. I've done this for cutting tiny model rocket parts.
You can even mill cross-slots for stops.
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DJ Delorie said:

That sounds pretty good. Except for the $260 price tag... :-o I'm kind of a build it yourself kinda guy... I could never get a crowbar that deep...

CGI script, eh? Can't see the inner workings of that from here. ;-) I've written some stuff in C, ASM, VB, HTML, JAVA, but geometry was, unfortunately, a long time ago. And programming was mostly a hobby...
Wrote the software for a PIC microcontroller based aquarium controller years ago, but haven't messed much with it lately... http://www.thevideodoc.com/preefs5.htm

I've been working out a plan, the ideas presented here got my lethargic brain working somewhat.
Hmmm - model rockets. I have built a few of those in my younger days. Spent weeks building them, painting them, and then losing them in treetops... ;-)
There was a show on History Channel a month or so ago, I forgot the name, that highlighted some of the model rocketeers in SoCA. Brought back fond memories of Land Sharks, Scuds, and M-80s.
Sorry I didn't see your post till now - the general noise level in here was a little high. But at least the 'IP troll' and his Caner have seemingly departed.
Thanks, DJ
Greg G.
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It's just perl.

Designed motherboards and wrote BIOS codes for them in a previous job. Work for Red Hat Inc at the moment. In my case, *woodworking* is the hobby :-)

Me too, although since I like building them more than flying them, I look at that as "making room to build more" :-)
Used to build RC airplanes too, but didn't like flying (or repairing) them as much as building them.
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DJ Delorie said:

DJ, You left out the 'a'. Both of them. <g>

Designed/built a PC-slot peripheral that allowed connection of such things as 16 port data acquisition, (E)EPROM & PIC programming, etc. http://www.thevideodoc.com/pelectr2.htm
This was back a few years, and I had designs and partially completed projects consisting of X-Y Gerber drilling machines and such.
But now you can get a set of proto-boards for $70 - one place even gives away some reasonably good software for PCB design.
But to top it off, my dad can beat your dad - any day. <bfg>
If it's any consolation - they are BOTH hobbies for me now. Got away from electronics due to the disposable nature of it all. Nothing has any temporal value. Went into software - Oh, Yeah, now that's a LOT better...
Red Hat - isn't that a free download? (I have an older copy.) How DO you make money at that... <g> How about Knoppix? Kinda neat to boot and run OS from a CD.
(And don't even get me started on open-source vs. Gates and Company.) I want to run Apache, but our customers ALL use Windoze. So I have to run it on our servers in order to troubleshoot their problems. Many, many problems. Every SP release problems. Obscure, bizarre problems. Problems that consume vast amounts of time... Arrggh!!!

Got into the RC planes about the same time as I got a drivers license. You can guess which one won out... Hmm... toys... or cars, toys... or women, toys... or freedom.
I guess age gives you the ability to relive your childhood - your way.
Thanks,
Greg G.
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I see you own a CMS. I think that's what I'd do. Forrest claims to make a blade that yields a glassy smooth surface with one of those.
I've never gotten a surface good enough for glueing off my bandsaur. Perhaps others have, but not me.
Or, cut them with the bandsaur and clean up with a disk sander.
Possibly cut them to rough size with a bandsaur then put each piece in a jig to be trimmed with a router? I'm thinking some sort of template with a ball bearing guided bit.

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George Max said:

Yea, but I just bought the WWII and hate to keep throwing money at blades. Plus, it's a 12 incher, and they run about $150 AIR.

Me either. Looks good, but never _quite_ lines up right.

This is the idea I'm toying with at this moment... Owen Lowe got me thinking about it when he said 'sander'...

Don't think I like the router idea, but the CMS or bandsaw with a jig, and then a flat disk sander would prolly do it.
Thanks,
Greg G.
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How about a BS and not so accurate cuts. Glue the pieces together until you get a half circle, do that again, sand those 2 half circles flat and glue them together.
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"The disk sander jig was a pretty good idea..."
Cutting the pcs. on a band saw then sanding them on a disc sander is OK, draw the outline of the segment on the wood, being careful to align the grain the right way, cut just outside the line, sand to the line on disc (or belt) sander.
" Glue the pieces together until you get a half circle, do that again, sand those 2 half circles flat and glue them together. "
This is what I typically do reguardless of how I cut the segments to begin with. The rec.crafts.woodturning forum might be a better place to ask this question.
Walt Conner
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Walt Conner said:

Thanks Walt.
And actually, I did. I posted it here first by mistake. Out of habit. Wasn't paying attention. Pick one or all.
Greg G.
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