| Pages:
1
2
3
4
..
6 |
carpenter
Oud Junkie
Posts: 248
Registered: 8-30-2005
Location: Eugene OR
Member Is Offline
Mood: brimming with hope
|
|
Don't forget that the direction you're planing in will change with the grain.
<< oooh. Great Idea!! I will do just that.>>
I draw a line across the blank for the square end of the half-pattern to line up with, also. Now if I'm a good sawyer, I got it pretty much made!
|
|
|
SamirCanada
Moderator
Posts: 3405
Registered: 6-4-2004
Member Is Offline
|
|
what kind of saw do you use?
I was thinking of running the bent ribs in the band saw while staying clear of the marks. mind you it seems a bit tricky and I could take my time and
hand saw them.
|
|
|
carpenter
Oud Junkie
Posts: 248
Registered: 8-30-2005
Location: Eugene OR
Member Is Offline
Mood: brimming with hope
|
|
I have a bandsaw with a fairly fine blade - 1/4", I forget how many tpi. Does the job.
If you're sawing already-bent ribs, and the line's on the convex side, there's this; also worked well for me:
|
|
|
Jameel
Oud Junkie
Posts: 1672
Registered: 12-5-2002
Member Is Offline
Mood: No Mood
|
|
Samir,
I use the inverted plane to remove the sawcut edge and get close to flat, (way faster than sanding) then tweak the fit with 150 or 180 sandpaper. Your
jack plane will be fine. If your vise jaws are flush with the top of your bench you can clamp the plane flush with the top, and that will give you
extra sole. Or not. Doesn't matter much since you'll be finishing with the paper.
Yes, get that first rib as close to perfect as possible. The subsequent ribs I dont use a template for at all. I have the rib boundaries marked on the
mould, then I transfer these marks (at neck, tail end and widest point) to one edge of a square but bent rib, take an old rib that you didnt use but
was close to shape and connect the marks on the inside of the rib. That way you can go to the bandsaw and cut to the line with the rib lying flat on
the bandsaw table (the tips of the rib are pointing up). Too bad you aren't closer. I could show you. 
|
|
|
carpenter
Oud Junkie
Posts: 248
Registered: 8-30-2005
Location: Eugene OR
Member Is Offline
Mood: brimming with hope
|
|
<< take an old rib that you didn't use but was close to shape and connect the marks on the inside of the rib. That way you can go to the bandsaw
and cut to the line with the rib lying flat on the bandsaw table (the tips of the rib are pointing up) >>
He's right as usual! Lots better! I was just saying, should you find yourself with outside lines ... well, it could happen. I wasn't sure where your
lines were.
Planing can be quicker than sanding, that's for sure - "plane first" is how I do it - but if the surface is all wiggly from rocking the rib on the
plane and inattention, make sure there's enough meat on the rib left for sanding-to-a-flat-finish. 'Fast' can be deceptive. One place I hate to be is,
"Oh, jeez; I sure wish I hadn't done that ..." Doesn't take long for Regret to show up; when it does, I've invited it somehow ...
Pay attention and win! And keep that rib flat on the saw table where the cut is, don't let it buzz up and down; you're just asking for it then.
|
|
|
jdowning
Oud Junkie
Posts: 3485
Registered: 8-2-2006
Location: Ontario, Canada
Member Is Offline
Mood: No Mood
|
|
I have always worked with cutting the rib profile close to size 'in the flat', then bending to shape and making the finishing cuts with an inverted
plane (as well as on a wide, flat, sandpapered surface) anything that works to get the rib joints as perfect and close fitting as possible with the
minimum of forcing. It should be a bit easier if the bowl is semicircular and every rib (theoretically) identical in contour.
My current project is a lute with significantly 'flattened' contour - where every rib will be different in profile from its neighbour requiring a
somewhat different technique - perhaps final fitting of each rib by planing the edges on the mold.
Once I 'get into it' and manage to figure out the best solution to this particular challenge you are welcome to drop by to see first hand what I do
(or to commiserate if I encounter difficulties!!). But by that time you may already have successfully finished your oud bowl!
|
|
|
SamirCanada
Moderator
Posts: 3405
Registered: 6-4-2004
Member Is Offline
|
|
Thank you all for the extremely precious and valuable information. I couldn't tackle this without all of you.
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
|
|
|
carpenter
Oud Junkie
Posts: 248
Registered: 8-30-2005
Location: Eugene OR
Member Is Offline
Mood: brimming with hope
|
|
Just do your best, keep your eyes open ,and remember for next time.
|
|
|
SamirCanada
Moderator
Posts: 3405
Registered: 6-4-2004
Member Is Offline
|
|
more progress
pegbox is almost done today. here is what happened last nite.
|
|
|
SamirCanada
Moderator
Posts: 3405
Registered: 6-4-2004
Member Is Offline
|
|
after filling to exact shape both sides and scraping for final smoothness.
after thinking about it... I should have cut bothsides at the same time and then I would not have had to do this.
|
|
|
SamirCanada
Moderator
Posts: 3405
Registered: 6-4-2004
Member Is Offline
|
|
here I am planing flat but at a slight angle the spacer blocks in the peg box.
I learned to use another block of wood right against it so it doesnt chip the very end of the block.
|
|
|
SamirCanada
Moderator
Posts: 3405
Registered: 6-4-2004
Member Is Offline
|
|
and now you can see the blocks being clamped and glued in.
|
|
|
SamirCanada
Moderator
Posts: 3405
Registered: 6-4-2004
Member Is Offline
|
|
I have bascialy scrapped the bending iron with a light bulb thing.
After watching the Saz building videos of yesterday I came up with an incredible idea to bend the ribs using a house hold clothes iron.
I clamped an aluminum tube to the bench and I can squeeze the wood between the iron and the form.
here it is with the back plate bent.
It took 2 minutes and done.
|
|
|
SamirCanada
Moderator
Posts: 3405
Registered: 6-4-2004
Member Is Offline
|
|
here you can see the plate laying on the back. to check the fit.
there are a few spots that needed lesser bending so I adjusted the fit like that.
|
|
|
SamirCanada
Moderator
Posts: 3405
Registered: 6-4-2004
Member Is Offline
|
|
and now I have the spreader jig bar that I will use to build the back.
I am going to use a plywood shape at the highest point for guidance purposes...
Tomorow I will carve out the neck and bottom block.
|
|
|
jdowning
Oud Junkie
Posts: 3485
Registered: 8-2-2006
Location: Ontario, Canada
Member Is Offline
Mood: No Mood
|
|
Did you use the steam setting on the household iron Samir - or just use the iron as a 'dry' heat source?
|
|
|
SamirCanada
Moderator
Posts: 3405
Registered: 6-4-2004
Member Is Offline
|
|
I used the steam setting mind you I didnt have much watter in there.
I didnt soak the hard maple either but I found that a lot of moisture happened trough condensation on the aluminum form. The peice of wood soaked it
up as I would glide it on there.
anyhow this is what I did
now my question is what should i have done?
|
|
|
Jameel
Oud Junkie
Posts: 1672
Registered: 12-5-2002
Member Is Offline
Mood: No Mood
|
|
| Quote: | Originally posted by SamirCanada
now my question is what should i have done?
|
It worked, what more do you want? Not sure your going to like doing it to a bunch
of ribs though...
|
|
|
SamirCanada
Moderator
Posts: 3405
Registered: 6-4-2004
Member Is Offline
|
|
well the beauty here is that since you have insider information...
I have some ribs all ready bent. I will have to tweak them thats all and I plan to use the dry heat on them only.
I think you know where the ribs come from :P
|
|
|
SamirCanada
Moderator
Posts: 3405
Registered: 6-4-2004
Member Is Offline
|
|
on the other hand the joints on the peg box failed!!!
I think that perhaps the block plane gave too smooths a finish for the glue to really grab it.
I used fish glue since I didn't feel like making fresh hide glue.
problem i think is that the fish glue is about 1 year old so it may have gone bad...
I will start over with some hot hide glue tomorrow after taking off the old glue.
|
|
|
Jameel
Oud Junkie
Posts: 1672
Registered: 12-5-2002
Member Is Offline
Mood: No Mood
|
|
Oh yeah, I forgot about those ribs...
I wouldn't bother with using hide on the pegbox. Titebond is fine for the pegbox. Never used the fish glue, but I've read plenty about luthiers not
liking it. Don't believe the hype about planes leaving too smooth a surface for gluing. It's baloney. I plane all my glued edges and haven't had a
failure yet. And that includes pegboxes all the way up to big boy joints like these. For reference, these gluing surfaces are 4" wide. Nothing better
than a plane for really getting a perfect fit.
|
|
|
DaveH
Oud Junkie
Posts: 526
Registered: 12-23-2005
Location: Birmingham, UK
Member Is Offline
Mood: No Mood
|
|
Is that the neck blank for your new base oud Jameel?
|
|
|
SamirCanada
Moderator
Posts: 3405
Registered: 6-4-2004
Member Is Offline
|
|
Sweet picture Jameel.
ok I will resort to titebond for the pegbox then.
Also I had a question for the backplate in the pegbox... how thin should it be?
|
|
|
jdowning
Oud Junkie
Posts: 3485
Registered: 8-2-2006
Location: Ontario, Canada
Member Is Offline
Mood: No Mood
|
|
It depends upon the type and quality of fish glue I suppose but I would be surprised if fish glue in general was any good for instrument work - used
alone that is - isinglass (sturgeon) glue mixed with hide glue and used hot may be a different story. The glue brand 'Seccotine' - which used to be
sold in tubes - is an example of fish glue that is best reserved for sticking paper not wood. Liquid hide glue is also no good for instrument
building.
As Jameel suggests a good synthetic woodworking glue is fine for permanent joints that will not be required to be separated, ever, for future repairs
- like the pegbox assembly.
You will need to be sure to remove all of the old fish glue before re-gluing. Hot water (followed by drying) might be sufficient. Hot hide glue might
be more 'compatible' than synthetic glues with any fish glue residues remaining but I don't know for sure. Nevertheless, I would still use hot hide
glue for gluing the pegbox backplate in case any future splitting of the backplate (it can happen) requires its removal and replacement or repair in
future.
I have never used your household iron technique for bending wood but I have used irons for softening hide glue joints when fitting or removing
soundboards or for applying veneer for example.
If you find the iron works OK for bending, the results of your trials may make you the expert in this technique - so let us all know how you get on -
success or failure.
I use a conventional bending iron for lute ribs either with dry heat or just a wipe with a damp cloth to reduce any scorching of the wood. Any
moisture will usually immediately 'flash' to steam at the bending iron temperature - and help the bending process - so the rib should be bone dry by
the time bending is complete. Steam bending (i.e. the wood is bent when saturated with water at boiling point) is not to be recommended for instrument
building as it might result in unwanted residual stresses that could be problematic in the finished instrument.
Lute ribs are about half the thickness of oud ribs so they can be more easily bent.
Jameel is correct about the perfection of the joint surfaces - the closer fitting the better from a strength (and appearance) point of view - although
most glues are quite forgiving in this respect, having a certain amount of 'gap filling' capability. Of course, it takes a great deal of skill to hand
plane close fitting joints to perfection - the wider the joint the more difficult it is. An example in the engineering field are lapped metal surfaces
(precision tool-room inspection blocks) that are so perfectly fitted that they stick together without any glue - only by molecular attraction! But, of
course, that perfect state cannot possibly be achieved with a porous material like wood.
Is that a new bench top Jameel? My workshop(s) are in the 'dark ages' in comparison - how do you keep yours so immaculate?
|
|
|
SamirCanada
Moderator
Posts: 3405
Registered: 6-4-2004
Member Is Offline
|
|
peg box almost done.
left is shaping and putting some pegs in there.
|
|
|
| Pages:
1
2
3
4
..
6 |
![[*]](images/xmbprobrown/default_icon.gif){kind=icon}
