Curved laminations in riser?

[cbatzi01]

Hi,

I am trying to add a curved lamination in my next riser and having trouble tweaking the fit.  I glued up the riser block, drew the larger radius, measured the thickness of the thin laminates and subtracted that to get the small radius.  I cut between the lines and sanded back to the lines.

I have spots where the outer/lam stack/inner mate perfectly, and spots where there are gaps.  I have been removing material from high spots, trying to tweak the fit, but i feel like it is getting worse.  Anyone have any recommendations for getting these three pieces to match up?

Thanks in advance!
-Chris

[Dan Bonner]

I take two equal sized blocks of contrasting woods, Glue them together with 1 drop of CA glue on each end, draw whatever design I want, cut it out on the bandsaw, swap the pieces, add phenolic and accents and glue it up. Built a ton that way with no problems. That sanding to the line BS is hard.

Bonner

[cbatzi01]

so, i am assuming that if you are using a normal BS blade, it's about .03 thick, but you want to put a stack of thin lams, say .1 thick, you need to remove more material and so do two cuts?

Do you go back and touch up the cuts with a sander to smooth it out?

-Chris

[LittleBen]

I think some people make a swing jig that cuts a clean radius curve as well ... that would probably also make things a bit easier, especially in conjunction with Dan's suggestion. Never done it so can't offer more info ... Hopefully someone with experience in this chimes in.

[David Flanrey]

Chris,

I do it like Dan posted.  After cut is made just a little light sanding to deburr it a little.  Then put what ever accents I want in it and glue it up.  

Seems to me that a .1 thick piece of anything would not be very flexible.  You want something flexible that you can squeeze together when gluing it up.  IMO

[cbatzi01]

Maybe I just have poor bandsaw technique!

.1 would be way too stiff.  I was thinking about 3 pieces of .03 material (dark/light/dark) sort of thing.

I have taken some very nice pieces of wood and completely bungled this operation....

[Swissbow]

I built a swing jig and it works great. If I want to put in a large accent stripe, I just reduce the radius and make a second cut. The parts fit together perfectly. All I have to do is clean the burs at the edges and I'm ready to glue up.

 

 

 

For this one I just made one cut. All the stripes together are approx. 1/4" thick.
 

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Andy

[cbatzi01]

Hi Andy,

This is exactly what I am talking about.  Do you have any pics or a description of the jig?  is it different than just a circle cutting jig?

Thanks!
Chris

[Robertfishes]

Use the search function. Type swing jig. a few pics will show up..

[Dan Bonner]

 
 

Just thought I'd post some pics of how I do this. It's the easiest way I have found and if your BS blade is good you don't have to do any sanding to get a good glue joint. If you do sand it's very minimal. There are a lot of other ways to do curved accents in risers and I've tried most. This is by far the easiest.

Bonner

[Dan Bonner]

Here is what they look like finished.
 
Bonner

[cbatzi01]

Those look amazing.  That's what I attempted to do, with poor results. I had to do a lot of sanding to close the gaps.  

Are you cutting both blocks at the same time, one on top of the other?

Used a brand new 3/8" 3-4 TPI blade, and I looked like it was appropriately tensioned.  I am blaming technique, or lack there of....


-Chris

[cbatzi01]

Those look amazing.  That's what I attempted to do, with poor results. I had to do a lot of sanding to close the gaps.  

Are you cutting both blocks at the same time, one on top of the other?

Used a brand new 3/8" 3-4 TPI blade, and I looked like it was appropriately tensioned.  I am blaming technique, or lack there of....


-Chris

[Dan Bonner]

Yep both at the same time stacked together.

Bonner

[Dan Bonner]

You don't need to make any allowance for the accents if you keep them pretty thin.

[cbatzi01]

I am guessing if you want to do thicker ones like Swissbow shows above, a swing jig you can adjust would be more consistent.  I hate building jigs though....

-Chris

[Dan Bonner]

May be. I never use anything thicker than a couple veneers maybe .025 and a 1/16" lam of phenolic between them. If you plan on making compound curves I would keep them thin. I assume a straight radius would allow you to build them as thick as you want if you adjust for thickness. You will be locked into the same flare design on every bow though.  That would bore me after a while.

Bonner

[talkingcabbage]

With a swing jig, set it up for the radius you want and cut one block, then cut the second block at the same setting. Match them however you want. I'll typically put a thin strip in between just to help set the colors off.
If you don't have or want to make a swing jig, do like Dan says. Works great. Just use a small dab of wood glue or super glue in the corners to stick the blocks together, or wrap with painters tape. Go slow and smoothly on the bandsaw. Lightly sand the burrs off. Add a strip of maple or white phenolic to set off the colors and you're done.