need to cut scarf's on thin material

[giantbeat]

hi guys, need some ideas from you.

I'm needing to cut some scarf joints on some very thin material, 1.5mm veneers to be precise. the pieces are at least 8-10" wide & quite long (min of 50" ish or more), i have had a good search around and the only thing i can think of is to set up a mini drum sander with the drum at a very slight angle, so i can feed the wood in clamped to a bigger board and trim it back in several passes

i do have a spare motor that can use, but before setup and start making things that i have not tried yet, anyone else got any ideas? this is something i will need to repeat frequently so I'm looking to setup a system not do a one off which i could probably sand in by hand.

cheers

G

 

[MikeG.]

Scarf.

It isn't a joint if it is in veneer, other than a butt joint. I'm great on scarf joints......not so special on veneer questions, so I'll leave that to someone else.

 

[giantbeat]

Scarf.

It isn't a joint if it is in veneer, other than a butt joint. I'm great on scarf joints......not so special on veneer questions, so I'll leave that to someone else.

sorry auto type got me, no idea what it was changing it to but it should have said Scarf

i generally do butt joints on all my veneer work (working with veneer is all i do), that's usually much thinner laminated pieces though, but cant do butt joints on this, I'm replicating some vintage work and the construction needs to be the same as the original style, didn't know what else to call it other than a lap joint maybe.

 

[MattRoberts]

Only thing I can think of is to use a shooting board very carefully to create opposing 45 degree bevels on the two pieces.

Not sure what benefit this will have over a butt joint on material that thin though?

 

[giantbeat]

Only thing I can think of is to use a shooting board very carefully to create opposing 45 degree bevels on the two pieces.

Not sure what benefit this will have over a butt joint on material that thin though?

shooting boards, cool thanks will have a think about how i would do it with one, i have several laying about the workshop.


the joint is on the same piece mate, it will be bent into a circle and each end joined, without trying to go into vast amount of info regarding the history & methods of musical drum construction, its hard to explain why it need to be done this way, but it does... i make 100's of butt jointed shells a year (both with straight vertical joins & also 45 degree) but BUT I'm tasked with replicating a vintage construction method, something that was more common in the 30's - 50's, the bevel end joints are 100% essential to authenticity not to mention that construction style & method massively affects a drum tone.

 

[custard]

the joint is on the same piece mate, it will be bent into a circle and each end joined, without trying to go into vast amount of info regarding the history & methods of musical drum construction, its hard to explain why it need to be done this way, but it does... i make 100's of butt jointed shells a year (both with straight vertical joins & also 45 degree) but BUT I'm tasked with replicating a vintage construction method, something that was more common in the 30's - 50's, the bevel end joints are 100% essential to authenticity not to mention that construction style & method massively affects a drum tone.

Knife cut through two overlapping pieces, just like traditional scotch glue and hammer veneering, but with an angled rather than a vertical blade. All you need is a jig to maintain a constant angle.

 

[giantbeat]

the joint is on the same piece mate, it will be bent into a circle and each end joined, without trying to go into vast amount of info regarding the history & methods of musical drum construction, its hard to explain why it need to be done this way, but it does... i make 100's of butt jointed shells a year (both with straight vertical joins & also 45 degree) but BUT I'm tasked with replicating a vintage construction method, something that was more common in the 30's - 50's, the bevel end joints are 100% essential to authenticity not to mention that construction style & method massively affects a drum tone.

Knife cut through two overlapping pieces, just like traditional scotch glue and hammer veneering, but with an angled rather than a vertical blade. All you need is a jig to maintain a constant angle.

ohhh thats interesting, would create a much shallower joint that i was thinking originally, but I'm not going to discard that... it certainly is one to think about, that's been added to the try pile.

thanks Custard.

 

[Beau]

If I have understood right I would make wedge shape guide and clamp it down to the veneer and either pare it off with a chisel or plane it being careful not to cut into the guide. Something like this

 

[giantbeat]

If I have understood right I would make wedge shape guide and clamp it down the veneer and either pare it off with a chisel or plane it being careful not to cut into the guide. Something like this

this would give me a very similar shallow join like custards suggestion.... I'm sure will work

but the overlapping join I'm talking about is usually 2" long minimum... so it starts paper thin & gets gradually up to the full veneer thickness over 2 inches of length at least

 

[Droogs]

The joint you are trying to replicate was traditionally done by hand using a toothing plane on a "donkey's ear" shooting board set at the correct angle of around 15 degrees. It's done at a shallow angle to allow a stronger joint overall.
I have some info on it somewhere and will see if i can dig it up for you tomorrow
hth

 

[giantbeat]

The joint you are trying to replicate was traditionally done by hand using a toothing plane on a "donkey's ear" shooting board set at the correct angle of around 15 degrees. It's done at a shallow angle to allow a stronger joint overall.
I have some info on it somewhere and will see if i can dig it up for you tomorrow
hth

amazing i would be so grateful, thanks so much.

 

[AndyT]

Shaker hat boxes have a long shallow taper on the inside end. The wood used is a bit thicker than your veneer, but looking at some of the many instructions or videos might show up something you can adapt.

The first one I found just had the wood clamped down to the bench and the taper planed away (with the wood in tension). This might work, or you could try a broad sanding block with coarse abrasive paper glued on to it if the veneer is too weak to stand planing.

 

[bugbear]

A friend's father does vintage aircraft repair, and super-shallow scarf joints are used on the very thin plywood he uses.

He just freehand planes them.

I did teach him how to sharpen though...

BugBear

 

[bugbear]

but the overlapping join I'm talking about is usually 2" long minimum... so it starts paper thin & gets gradually up to the full veneer thickness over 2 inches of length at least

You said 1.5 mm veneer, and 2" is around 50mm so the angle is atan(1.5/50) = 2 degrees (ish)

(or 1:33)

This guy uses a router jig to make a 1:10 scarf in 6mm ply; the trailing edge at 1:10 already looks mighty feathery.

http://forum.woodenboat.com/showthread. ... -Jig-Ideas

BugBear

 

[Brandlin]

i've seen bowyers use a tapered base board on basically a drum sander to allow a repetitive shallow angle to be sanded into a rhin board. though admitedly they are working around 6mm laminates not 1.5mm veneers. But i think building a small drum sander and a shallow taper base board might be simpler than an angled head sander? different tapers mean different length scarf joints without altering the sander too

 

[profchris]

If you're using solid wood rather than ply then I think you need a toothing plane, worked at 45 degrees to the grain direction. I regularly work with 2mm board for musical instruments, and am constantly breaking out the far edge when using a conventional plane (note to self, switch to the toothing plane earlier!).

For such a shallow scarf precision angles are a bit meaningless - assuming a 2 inch overlap, mark out 2 inches and shave it back until it looks like a nice flat taper. When you glue up, I'd glue round a former to ensure you keep the round, and the veneer will conform pretty well to the shape of the former.

With my woodie toothing plane I'd guess 2 minutes work per side, so 4 minutes planing overall. Unless you're making a whole barn full of drums, this is probably the quickest option. The hard part is finding a toothing plane

 

[profchris]

Ahah, a toothed plane available new:

http://www.ebay.co.uk/itm/plane-tooth-c ... SwXrdZ7bgD

 

[Jacob]

Just guessing - but what about feathering one end of the board, glue clamp and bend around the drum shape, lapping the free end over the feathered, then trimming it back when the glue has gone off?

PS much like what profchris said above, now I've read it!

 

[worn thumbs]

If it is for a drum type job,its a little more challenging than lengthening a single piece.To add another piece to arrive at a longer piece it is easiest to stack the two pieces with the ends separated by the length of the scarf and just plane away the excess.I have known times when a narrow strip of double sided tape was handy to hold down the feather edge if the veneer tended to curl and a palette knife or similar was good for breaking the joint.I wouldn't have thought a toothing plane was necessary and the grooves may be visible when the joint is cleaned up-is that a problem?I have scarfed with as gradual as a 1:12 taper and tapered the ends of battens with even shallower gradients using no more than a smoothing plane.

 

[giantbeat]

If you're using solid wood rather than ply then I think you need a toothing plane, worked at 45 degrees to the grain direction. I regularly work with 2mm board for musical instruments, and am constantly breaking out the far edge when using a conventional plane (note to self, switch to the toothing plane earlier!).

For such a shallow scarf precision angles are a bit meaningless - assuming a 2 inch overlap, mark out 2 inches and shave it back until it looks like a nice flat taper. When you glue up, I'd glue round a former to ensure you keep the round, and the veneer will conform pretty well to the shape of the former.

With my woodie toothing plane I'd guess 2 minutes work per side, so 4 minutes planing overall. Unless you're making a whole barn full of drums, this is probably the quickest option. The hard part is finding a toothing plane

the toothing plane seems the way top go for authenticity, it explains the marks i have found on some makes of drum shells... but i still think it will be too slow for production, barn fulls is the idea ... i already make hundreds of drum shells per year for my & several other drum companies, but we make them the modern way which is much easier using .6mm veneers & making our own plywood & the putting many layers of them in the mould.

I'm going to pick up a toothing plane up & try it whilst still looking for a merchandised option.