Calculating coopering angles and stock thickness needed

**TimberNut** · 29th February 2008, 04:56 PM

I've been trying to find out an easy way to calculate the maximum wall thickness of curved walls for either turned pieces, or curved box lids, for a given stock used.

After searching around I couldn't find exactly what I was after so I've created a spreadsheet to answer those questions.

It'll work for wood turners wondering
if i want to glue timber together to turn a vessel of outer diameter 150mm and minimum wall thickness of 10mm, what size stock do I need to glue up (and at what angles?) with minimal wastage.

If you are looking to glue timber strips together to make a curved lid for a box, or similar, and you know the max curve height and wall thickness you want, again, this will work.

For example if your stock timber is 16mm thick,
you can instantly see the difference 10 staves 60mm wide will give, vs 20 staves 30mm wide - same total arc created, but different wall thickness available.

It's fairly self explanitory. hope it helps.

Timbernut

**Brown Dog** · 29th February 2008, 05:23 PM

Nice one timber nut....I think that will really come in handy

cheers
BD

**griffithpark** · 1st March 2008, 04:47 AM

I've been using the instructions that come with Lee Valley's birdmouth bits. This will be more flexible.
Thanks.

**TimberNut** · 2nd March 2008, 07:49 PM

No problems guys. I'm sure there are other ones around that can do similar stuff, but I couldn't find one that did this precisely and it was what I needed. Happy to share.

Timbernut.

**TimberNut** · 8th March 2008, 05:46 PM

having just used my own spreadsheet, I've realised there's an error in the calculations. I've fixed it, see new attachment.

Timbernut.

**kaharoa** · 2nd February 2011, 04:33 AM

Thanks so much for posting this! Anyone used it to make a barrel?

**TimberNut** · 7th February 2011, 09:44 AM

[Quote] Anyone used it to make a barrel?

Yeah, me! (but then, that's why I wrote it in the first place)

**kaharoa** · 7th February 2011, 06:38 PM

I'd love to see a photo if you have one.

**munruben** · 8th February 2011, 08:31 AM

Timbernut, thanks for the info. I suggest you post this in the Library so it will be available at all times to forum members; otherwise it will just be lost among all the other posts.

**TimberNut** · 8th February 2011, 09:42 AM

I can't find a picture of the barrel, but I have a picture of a toilet roll holder I made using these calcs. (From memory, it was the project that prompted me to write this calc spreadsheet in the first place).
Attachment 160744

Since then I've used it to make a small barrel (for holding flour in the kitchen). I used the same spreadsheet, given that I knew the outer maximums for both the top/bottom (smallest outer diameter) and the middle of the barrel (largest outer diameter). It worked a treat.

Thread: Calculating coopering angles and stock thickness needed

Thread Tools

Search Thread

Calculating coopering angles and stock thickness needed

Very nice!

version 2

Similar Threads

Stock thickness for finished dimensions? How does it work?

New guy, need help calculating angles

Coopering a Wooden Bucket

Coopering angles

Head Stock & Tail Stock extention plates

Tags for this Thread

Posting Permissions