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HORN SPEAKERS #3: Cutting the Wedges to fit the pattern

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Blog entry by stefang posted 12-17-2019 12:58 PM 647 reads 1 time favorited 12 comments Add to Favorites Watch
« Part 2: Time for the rubber to hit the road Part 3 of HORN SPEAKERS series Part 4: Marking and more Cutting »

Here is a teaser so you can get an idea of the size of the horns. Keep in mind that there will be trumpet like ends attached to the horns. I will be making these end pieces with plywood rings similar to segmented turnings and turn them on my lathe.

Once the individual segments were cut, they needed to be cut into wedges so that they would form the curl in the horns. The outside thickness (or top) of the segment squares would remain the same. The inside edge, (or bottom) of each square would vary from about 3mm or 3/32” to 5mm or slightly less than 1/4”.

Perhaps the biggest challenge of the whole project was finding a way to cut these wedges dead accurate leaving a very flat surface on the cut side that would glue-up without any gaps. The dimensions were taken directly from the pattern for each segment as shown below.

After several failures I finally came up with a procedure that worked. This required the following:

  1. A clearly marked cut line. This was accomplished by gluing white paper to the top of each square before marking. 1st photo below
  2. A hefty woodblock to manually hold the workpieces firmly against the miter saw fence. Each workpiece was stuck to the woodblock with double sided tape. I was able to cut two wedges with one piece of tape before replacing with fresh tape 2nd and 3rd photo below

After cutting all the wedges they looked like this photo below

I ran into a lot of problems cutting these wedges before coming up with procedure outlined above. I tried several methods of cutting them which failed. I first tried to do it with my bandsaw because I couldn’t come up with a safe way to hold the on-edge workpieces in the miter saw. The cuts were not perfectly flat or particularly accurate and the changing angles required continual adjustment to the table angle, which is not the easiest to do with my bandsaw. Here is a picture of that failed set-up below

The other problem was making a clearly marked cut-line which was eventually solved with the papered edges.

My next blog in this series will cover additional necessary markings, cutting to round on the scroll saw and glue-up.

Thank you for following along. Please let me know if you have any questions or need to clear up any of my wordy explanations. You may have better ways to do some of the operations outlined above and if you do please share them.

-- Mike, an American living in Norway.



12 comments so far

View Serradura's profile

Serradura

183 posts in 2714 days


#1 posted 12-17-2019 02:05 PM

This is quite an interesting blog to follow!

-- Não só Serradura, Tomar, Portugal http://www.notjustsawdust.com

View madts's profile

madts

1941 posts in 3110 days


#2 posted 12-17-2019 04:13 PM

The old saying “Where there is a will, there is a way” comes to mind.

Nice job Mike.

—Madts.

-- Thor and Odin are still the greatest of Gods.

View doubleDD's profile

doubleDD

9464 posts in 2813 days


#3 posted 12-17-2019 04:17 PM

I like the way you solved the problem of cutting the wedges. This could be helpful in the future for similar projects. There is no failure, only different ways of doing it the wrong way. I can imagine what the sanding will be like.
Kudos to you Mike.

-- Dave, Downers Grove, Il. -------- When you run out of ideas, start building your dreams.

View MrWolfe's profile

MrWolfe

889 posts in 894 days


#4 posted 12-17-2019 05:57 PM

Great blog!!!
I like the solution for cutting the angles. I imagine each segment has a slightly different angle and you are having to make small adjustments on the miter saw for those?
This seems like a project where making multiples of each piece as extras would be a great idea.
Thanks for sharing this project with us all.
Jon

View stefang's profile

stefang

17039 posts in 4104 days


#5 posted 12-17-2019 06:01 PM

Thanks all for the comments.

Dave I have already rough smoothed it with my Dremel. It’s a little difficult to see all the bumps so I will be painting it with a color that matches the plywood to help me see where they are before I begin hand sanding. I’m expecting this work to take a lot of time, so I will listen to some good music while I do it to keep my sanity.

Jon Yes, the angles change frequently to make small adjustmentss to the 11 different radius’s involved, but usually the same angle can be used on a few in a row before a change. Remember, with two horns there are about 112 pieces, 56 of different sizes for each horn so making duplicates would make an already laborious process even more difficult.

-- Mike, an American living in Norway.

View a1Jim's profile

a1Jim

118065 posts in 4347 days


#6 posted 12-17-2019 07:14 PM

I’m so enjoying this blog, thanks so much for sharing Mike

-- https://www.artisticwoodstudio.com/videos

View shipwright's profile

shipwright

8554 posts in 3568 days


#7 posted 12-18-2019 12:27 AM

Go Mike! You’re on a roll now!

-- Paul M ..............the early bird may get the worm but it’s the second mouse that gets the cheese! http://thecanadianschooloffrenchmarquetry.com/

View mafe's profile

mafe

12592 posts in 3859 days


#8 posted 12-18-2019 07:38 PM

Woooohoooo!!!
That is so cool!
I can’t wait to see how this blog ends and look forward to follow the steps.
Best thoughts,
Mads

-- MAD F, the fanatical rhykenologist and vintage architect. Democraticwoodworking.

View splintergroup's profile

splintergroup

3777 posts in 1992 days


#9 posted 12-18-2019 09:30 PM

You have the stick-to-it-ness of a dog and a bone Mike. Looking forward to seeing everything all cleaned up and shining!

View stefang's profile

stefang

17039 posts in 4104 days


#10 posted 12-19-2019 01:21 PM

splintergroup I have found out (probably too late) that failure is really only experience that paves the way to success. In this case though I am still suffering from a very bad shoulder due to all the miter sawing which was the result of having to make 6 of these to finally get it right. This is not a cry for pity, just a warning about doggedness!

-- Mike, an American living in Norway.

View justoneofme's profile

justoneofme

828 posts in 3250 days


#11 posted 12-19-2019 03:49 PM

Ingenuity is your middle name Mike! These are looking incredibly awesome!!

-- Elaine in Duncan

View stefang's profile

stefang

17039 posts in 4104 days


#12 posted 12-19-2019 06:34 PM

Thanks Elaine. I just hope they turn out ok.

-- Mike, an American living in Norway.

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