German Ring Turning - cutting on bandsaw

[Truffuls]

With regard to the AAW Fall Contest and the article in the recent Journal by Tim Yoder.

I have my first ring completed and now it is time to cut it on the bandsaw.

There is not enough meat on either side to safely support this through the bandsaw.

I'm not a skilled jig maker and don't have a lot of spare lumber or time.

I'd like to bounce an idea off your collective wisdom to see if it would work:

If I wrap the ring in plastic wrap and place it in a box (wood or cardboard), then squirt in expanding foam insulation around the ring until the box is full and let it set up, would the foam provide enough stability for me to run it through the bandsaw?

If not, do you have any ideas on how to safely run it through the bandsaw, knowing that I'm not a jig maker and don't have spare lumber.

Also, this "test" ring is spalted maple and kinda punky in spots so it isn't the strongest piece of wood.

Thanks in advance!

 

[john lucas]

I' ve made a couple or ring turnings and didn't have any trouble cutting them on the bandsaw. I use an auxilliary table on the bandsaw with a piece of wood that rides in the miter slot. In most cases I haven't needed a clamp to hold the piece but I uses all-thread rod and nuts on both ends of the jig and scrap boards to be the clamp to hold the pieces to be cut.

 

[Dreher]

Why not use a thin kerf handsaw? That would be much simpler that packing a box with foam.

 

[Truffuls]

handsaw

😱 Handsaw?, through a thick hunk of maple with really thin edges of semi punky (brittle) areas?? No thanks. I don't own a handsaw sharp enough to tackle that task. I need to be able to cleanly cut this ring into 8 pieces.

Spraying in expanding foam would be extremely easy and an instant form fitting support system. My only question was if the foam would support the wood.

I'd consider a scrollsaw if I could get my hands on one able to handle the height.

Why not use a thin kerf handsaw? That would be much simpler that packing a box with foam.

 

[Ken Grunke]

Isn't your ring self-supporting as it sits on a flat surface? Most any turned ring would be. Then a half of a ring would be less stable, a quarter-ring even more so but still, it should sit flat unless the higher points in the profile are near the center. Then the entry and exit cuts through the ring get kind of scary, being up off the bandsaw's table.

If that's the case, your spray foam idea sounds worthwhile. Probably doesn't need a box around it to contain the foam, just put the ring on a flat base of something - cheap paneling scrap, or even cardboard or posterboard--then spray gobs of foam in 8 spots around the circle. I would agree that plastic wrap or just a sheet of foodwrap is necessary, otherwise it would be a nightmare pulling the foam and wood apart.

 

[Truffuls]

Plan of attack

OK, I've foraged around at work and came up with a beefy cardboard box big enough for my ring and found some very dense, strong foam packing pieces.

Here is my plan of attack:

• Wrap ring in plastic wrap,
• Line box with plastic wrap
• Place sturdy foam pieces around edges to support ring
• Squirt in Latex Foam insulation to fill voids and anchor supports in place.

Once I make the first cut I will:

• Tape the box back together,
• Lift ring/foam unit
• Rotate 90 degrees
• Make Next Cut
• Tape box back together
• Cut first diagonal, tape, cut next diagonal

If I don't lose an arm I'll let you know how it goes. 😀

 

[Truffuls]

No, Ken, the core is the tallest point. Even if the other points of the ring were the same height I would not trust the delicate edges to support the force of the blade. The wood is punky in spots.

Isn't your ring self-supporting

 

[jwtaylor]

Truffuls did you trim the tenon flush with the outer most leaf points (see step 26)? I think that is being done to give you a flat surface, on the side, to allow you to run it through the band saw. Just looked at step 27 and that is the idea.

John Taylor

 

[GeorgeH]

How about running a tight fitting dowel (turn one if you need to) and slip the ring over the dowel. Support the dowel on blocks mounted on a flat piece of scrap wood and use that "jig" to support the piece as you cut it?

 

[john lucas]

I think you can simply slip some heavy cardboard or even wooden wedges underneath the parts of the ring that don't sit flat. Use a sacrificial board. Hot glue these in place if necessary. this should support the ring for cutting.

 

[Truffuls]

Success!

I found the perfect size box, wedged the ring in with the dense packing foam I had and didn't even need to use the expanding foam insulation. It was a snug fit so I was confident that it would be ok.

Made cut one, rotated ring 90 degrees, taped it and the box back up, ran it through again, rotate, tape, cut, then for the last cut I turned the box and cut rather than trying to move the ring in the box.

The last cut was a bit dicey, there was movement, the cut not perfect, but for my first go at it, I'm happy.

I have to sand the 8 pieces then scroll saw the stems & finish, but I'm quite happy with the whole project.

Now that I have the experience I'm more willing to seek out the perfect turning blank to do this again.

This was wet, spalted, slightly punky maple and I used a leaf from the same species as my template. The bottom of the leaf got botched because my blank was not big enough and I could not get in deep enough on the bottom coves. The blank was roughly 4 3/8" wide and a little over 9" diameter. Again, too small for my leaf but it was fun.

Thanks for all the ideas and support!