ODS head

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Stephen1966
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ODS head

Post by Stephen1966 »

Halfway through building the head now just getting this thread started with a few pics and some general information. I'll be following up with some plans in metric measurements.

ODS Head - Metric.pdf
Scale drawings of the assembly
(328.13 KiB) Downloaded 97 times

The pine board has been sitting under my bench - air drying - for about four months so it's nice and light now. Pine is a variable wood though, extremely soft straight grains with extremely hard knots and pins. I gave it the air drying treatment so that any knots or pins would work loose. If they do, it's a simple matter of filling them with 5 minute epoxy. The lay of the board though and the knots and pins all looked good, so no filler required just yet.

I build the cabs and heads with half-blind dovetails. Extremely strong joints. It takes a while to set up the jig but it's ten minutes of a job to dovetail the sides when its ready. I use test pieces to set it all up. If you have a dovetail jig like this, don't give up. Once you figure it out, it all makes sense and you will be producing precise dovetails in no time.

Here's a dry fit of the carcass:

IMG_20230325_190119.jpg

Next, I wanted to insert the cross bar... for this, I used a Stanley No. 71 hand router. I'm not averse to using power tools but the hand router is just so much quicker than setting up a power router. If you can find one of these, snap it up. I don't think they make them anymore but they are a very useful piece of kit when you don't want to go setting up for power router. Of course, you could do this rebate with a sharp chisel and a keen eye but the no.71 will give you press-fit results every time... This one, needs the bit sharpening but for a hidden joint, it's fine.

IMG_20230325_201407.jpg

Here's everything as a dry-fit. It's all nice and tight here, solid and I can handle this without anything falling out or falling apart.

IMG_20230325_203833.jpg

Next, I will be marking and cutting out the template for the front panel cut out.
Last edited by Stephen1966 on Sat Apr 01, 2023 9:55 am, edited 2 times in total.
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Re: ODS head

Post by Stephen1966 »

When you're making a one-off head like this one, the marking up takes time but the biggest time is invested in making templates. Two hours to make, two seconds to use!

IMG_20230327_141037.jpg

The most challenging part of making the templates is to make sure the edges which make up bearing surface are exactly perpendicular. Templates like this, for the cutout in the back plate are made by first drilling holes in the corners and then using a jigsaw to remove the excess. You will see here, that after drilling the hole in the top right corner I had some tear-out that required repairing. If this was for anything more than a one-off, I would finish this template off and then use it to create another using a router... that's a trick from routing out the sides of guitar bodies. Creating the first template using hand tools you have to go very carefully and getting all the bearing surfaces perpendicular is a real challenge. However, when you create the duplicate template using the router, all the sides are cut exactly perpendicular by the router bit. Any imperfections there can usually be sanded out lightly.

IMG_20230327_141253.jpg

With the carcass glued up now it's time to fit the internal cleats. Another little trick I learned from setting fingerboards on guitar necks is to use a staple to accurately position the glued surfaces together. With no other fixing points in the two surfaces the problems arise when you apply the glue and clamp them together. The racking and torsion of the clamps can cause the two surfaces to slide on the glue out of position. Putting a couple of staples in the cleat like this also provides locating holes in the corresponding piece which are useful because when it's smothered in glue, you can feel when the staple goes into the locating holes. It's an extra little step but it saves having to remove a poorly located piece, clean up, and start again.

IMG_20230327_212520.jpg
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Re: ODS head

Post by Stephen1966 »

The horizontal, chassis rails provide 18mm [correction: 9mm] of clearance between the top of the chassis when it's part way in, to provide clearance for the screws that will be used to attach the handle on top.

[Edit: check the length of the screws. The tip of the screws I used on a Fender handle were flush with the ceiling of the cabinet so with the T nuts - epoxied in position - the clearance needed was only about a millimetre. 9mm is more than adequate!]

IMG_20230329_135230.jpg

The bevel on the back edge of the cross bar takes the chassis up to roof of the head.

After rounding over the external edges of the head with a 1/2" router bit and lightly sanding off the arris edges on all the exposed square edges, followed by a final sanding it's ready for spray painting the interior. Black of course :D Which is where it is now. I will be giving it a second coat shortly and then leaving it overnight to cure. Ready for the tolexing tomorrow.

IMG_20230331_201406.jpg
IMG_20230331_201425.jpg

If you look at the first post, I've added the drawings I used.
Last edited by Stephen1966 on Tue Apr 04, 2023 1:58 pm, edited 1 time in total.
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Re: ODS head

Post by Stephen1966 »

Before we start the tolexing it's a good idea to check the chassis mounting holes are where they're supposed to be.

IMG_20230402_103511.jpg
IMG_20230402_103445.jpg

Also, before spreading the glue, to mark where the had sits on the first side of tolex.

IMG_20230402_112746.jpg

Taylor's head tolexing video fits right in with this build... You've probably seen it before. If not, he makes it look easy :lol:

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Re: ODS head

Post by Stephen1966 »

So this is disappointing! After finishing the tolex I'm attaching the fittings and I come to the corners...

IMG_20230402_163009.jpg

This is obviously unacceptable. I think I must have the thinnest tolex in the world :lol: These are Fender corners and measure a tad over 20mm wrapover - looking around I don't see any that are smaller. Having set my heart on this style, I'm probably going to have to go with a cutaway style. I'll put these Fender corners away and save them for the next cab I cover in suede. Meanwhile, it's back to the shop :oops:
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Re: ODS head

Post by Stephen1966 »

Just have to find some different corners now and it's (mostly) all done. I have to fit the chassis before I can fit the aluminium fascia bar as it's fixed flush with the chassis front plate. Then, once I have the corners I can finish it off with the feet.

I prefer to use threaded inserts for the back panel. These, won't strip the way woodscrews strip the wood if they are overtightened, and I have some nice black flat-head screws somewhere which will look the business.

IMG_20230402_214541.jpg
IMG_20230402_214556.jpg
IMG_20230402_215002.jpg
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ijedouglas
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Re: ODS head

Post by ijedouglas »

Stunning job!
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Re: ODS head

Post by Stephen1966 »

ijedouglas wrote: Mon Apr 03, 2023 1:49 am Stunning job!
Thanks Ian.
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M Fowler
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Re: ODS head

Post by M Fowler »

Very nice cabinet. Not easy for me wrapping cabinets.

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alkuz1961
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Re: ODS head

Post by alkuz1961 »

Stephen1966 wrote: Sun Apr 02, 2023 3:01 pm So this is disappointing! After finishing the tolex I'm attaching the fittings and I come to the corners...


IMG_20230402_163009.jpg


This is obviously unacceptable. I think I must have the thinnest tolex in the world :lol: These are Fender corners and measure a tad over 20mm wrapover - looking around I don't see any that are smaller. Having set my heart on this style, I'm probably going to have to go with a cutaway style. I'll put these Fender corners away and save them for the next cab I cover in suede. Meanwhile, it's back to the shop :oops:
I think you've started to get upset prematurely. And you have the opportunity to apply a design that you like. The original Fender corners are really designed for the thickness of panels thicker than standard ones 3/4 (19мм)
IMG_6206.jpg
https://www.banzaimusic.com/Fender-2-le ... -of-4.html
But on Dumble amplifiers, other corners have always been used, like this - https://www.banzaimusic.com/Steel-corner-CS-2-WA.html
IMG_6207.jpg
IMG_6208.jpg
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Re: ODS head

Post by Stephen1966 »

M Fowler wrote: Tue Apr 04, 2023 2:54 pm Very nice cabinet. Not easy for me wrapping cabinets.

Mark
Hi Mark, Thank you... it's true, tolexing takes a bit of practice but that video is pretty good. I like the way he wraps the short end of the seam under the long end before cutting the seam. Avoiding lifting the short end to pull out the remnants from the long end, avoids pulling the glue off the carcass resulting in a stronger seam, less likely to lift with age and abuse. One thing he didn't show - perhaps he didn't need it - was using a heat gun to make the tolex more pliable when we wrap it around corners. The compound curves of the cutout at the front are the most challenging. Another thing, is to change the blades often, they go dull pretty quick when cutting through tolex into wood.
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Re: ODS head

Post by Stephen1966 »

alkuz1961 wrote: Tue Apr 04, 2023 6:54 pm
Stephen1966 wrote: Sun Apr 02, 2023 3:01 pm So this is disappointing! After finishing the tolex I'm attaching the fittings and I come to the corners...


IMG_20230402_163009.jpg


This is obviously unacceptable. I think I must have the thinnest tolex in the world :lol: These are Fender corners and measure a tad over 20mm wrapover - looking around I don't see any that are smaller. Having set my heart on this style, I'm probably going to have to go with a cutaway style. I'll put these Fender corners away and save them for the next cab I cover in suede. Meanwhile, it's back to the shop :oops:
I think you've started to get upset prematurely. And you have the opportunity to apply a design that you like. The original Fender corners are really designed for the thickness of panels thicker than standard ones 3/4 (19мм)

IMG_6206.jpg

https://www.banzaimusic.com/Fender-2-le ... -of-4.html
But on Dumble amplifiers, other corners have always been used, like this - https://www.banzaimusic.com/Steel-corner-CS-2-WA.html

IMG_6207.jpg
IMG_6208.jpg
Thank you! Yes, it makes sense that American cab makers would use Imperial sizes. The first you showed are like mine here - even the measurements are almost exactly the same. The second - let's call them "Dumble - corners only issue I can see is that the internal radius is 11mm whereas my cab has 1/2" roundovers. I think I could get away with a 12mm roundover, but 11mm would probably be too noticeable. These, from Tube Town https://www.tube-town.net/ttstore/dumbl ... ilver.html appear to be exactly the same. Alternatively, on discovering there is a second page there (!) I saw these https://www.tube-town.net/ttstore/set-c ... crews.html. I think it's likely I will get these but I'm currently waiting for TT to get back to me to confirm the returns policy if they don't fit. They've already told me they are "similar" to Fender corners but I don't know if that means I should trust the dimensional drawings provided. The measurements you took off your Dumble set and their dimensional drawings, illustrate it's best to ask first.
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Re: ODS head

Post by alkuz1961 »

I have used such angles many times, buying them in TT. And I also rounded the edges with a 1/2-inch rouret bits. Yes, there is a very small gap in the middle of the edge, but it looks almost imperceptible
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Stephen1966
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Re: ODS head

Post by Stephen1966 »

alkuz1961 wrote: Wed Apr 05, 2023 4:46 pm I have used such angles many times, buying them in TT. And I also rounded the edges with a 1/2-inch rouret bits. Yes, there is a very small gap in the middle of the edge, but it looks almost imperceptible
That's fine looking work - well done :D

Yeah! I think you can get away with it if you aren't looking for it. I honestly don't know where they get the 11mm radius from though, in imperial the closest is 7/16" and I wouldn't have thought that is a size MrD would have used. 11mm bits are available as well though.
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Re: ODS head

Post by alkuz1961 »

I think you can take into account the wood radius of 10 mm plus the thickness of tolex, this will be 11 mm. But I have never seen real headshells or cabinets with such facets. Always 1/2
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