Well.... finally got everything in place and set up and gave it a test with a platter. The turning went great...love the lathe... this is nothing spectacular but I'm pleased with how it came out.... it's about 12 1/2" X 2 1/2".....
Platter.jpg
[OP]
Contributor
Well.... finally got everything in place and set up and gave it a test with a platter. The turning went great...love the lathe... this is nothing spectacular but I'm pleased with how it came out.... it's about 12 1/2" X 2 1/2".....
Platter.jpg
Member
Looks great, Barry! What lathe did you get?
[OP]
Contributor
Thanks Phil....I went for the Laguna Revo 18/36.....Originally Posted by Phil Anderson
Contributor
Well I think it's very nice. It adds a subtle level of visual interest.
RD
Contributor
Getting a flat bottom is far more difficult than one might think - nice work, and no doubt the Revo made it far more enjoyable.
Left click my name for homepage link.
Contributor
Yes it is. One of my biggest challenges.
[OP]
Contributor
Thanks Richard and John.....at the moment I use a 1" round nosed scraper to finish off the bottoms....am thinking of getting a 1" flat scraper thinking it may be better for something like this platter...what do you use and do you think the flat one would be better than the round one?
Contributor
Barry, I have done one or two pieces with a flat bottom, though I now avoid that feature. I used a rounded negative rake scraper followed with a piece of flat wood as a sanding block to achieve a smooth, flat surface.
Except for certain pieces like yours, I think curves are more appealing and easier to accomplish.
Left click my name for homepage link.
[OP]
Contributor
Thanks for the info John.... I have to admit that I don't really know what a negative rake scraper is or what advantage it has over a regular scraper.. I have this one http://www.leevalley.com/en/Wood/pag...33,43164,43167 and when I see pictures posted here of negative rake scrapers they look the same to me as the one I have...maybe you could explain the difference to me if you wouldn't mind...
Contributor
If you take your scraper and grind a short 15* bevel on the top side, then grind the lower bevel lightly to raise a bur on the edge, you will have a negative rake scraper.
The advantage is a cleaner cut and less tearout.
BTW, for light use it is hard to beat the Benjamin Best square edge scrapers from Penn State. At $17 each, one can afford to play with various configurations such as special use tools.
Left click my name for homepage link.
[OP]
Contributor
Thanks John... I'll try that....
Moderator
Barry,
When I turn a flat bottom with a flat ended scraper like that I do two things: grind it with a top bevel (the negative rake) and radius the corners a bit. The negative rake makes the scraper much easier to control and can give a better surface. Knocking the sharp points off the corners help prevent digging them into the wood if the scraper is not held perfectly perpendicular.
That said, I take out any ripples on flat bottoms (used mostly on platters) by hand with a small hand-held scraper. With the lathe off, I scrape with the grain for the most part. This not only quickly removes any ripples but any issues common in the center. (It's not so useful with larger undulations.) I have a variety of small hand scrapers, some flat or mostly flat, some curved - they will handle almost any inside bottom of bowls and platters as well as wings of square/squarish platters/plates, outside and in. I used one the other day to remove some evil tearout in the endgrain on the side of a vessel. Some of the scrapers are thin like cabinet scrapers, some I got more recently are thicker, hardened steel. Look up StewMac scrapers.
Once scraped, usually only a relatively little amount of sanding is needed. I usually do this by hand as well. I use a sanding block of sorts, a piece of sand paper held over a soft backing - a Magic Rub eraser for most things:
sanding_soft_block.jpg
JKJ
Member
I'm interested in how the contrasting S-shape was done.
My guess is that the main block of wood was cut into two pieces, with an S-shaped cut, and then glued back together with a strip of the contrasting wood in between. Is that how it was done?
Contributor
Glad to know it's not just me!
RD
Moderator
Barry, I posted these pictures recently in another thread. The first one is of some small scrapers I made mostly for detail, the second is of some larger scrapers ground to work on the inside and outside of bowls, platters, and such. You can see how each edge has two bevels and how much they vary. The angles of the bevels do change how the tool works but are not very critical for most use.
scrapers_small_thompson.jpg scrapers_neg_rake.jpg
I didn't read all the responses yet but in case no one has answered - a negative rake scraper (NRS) is just a scraper with a bevel cut on the top side as well as the bottom. The shape and the amount of the bevel depends on what you want to do. The curved edge scrapers are perfect for smoothing away tool marks on a bowl.
There are several differences between the standard scraper and the negative rake. The biggest is the NRS are more controllable. A standard scraper is usually used with the handle raised so the flat on the top of the tool and therefore the cutting edge is angled downward. This lets the scraper move easily away from the wood in the event that it bite too hard into the wood. The NRS has this angle built into it so it is usually held horizontally on the rest and presented straight into the wood. A catch with a normal scraper can be spectacular! It is actually difficult to get a catch with a negative rake scraper. Holding it flat on the rest makes it easier to hold and control too since you don't have to hold the handle high.
Just like a regular scraper you do have to have a "burr" the edge of an NRS. It doesn't need to be much but you should be able to feel it with your finger when you touch the upper bevel. "Traditionally", woodturning scrapers were used with the burr you get from a grinder. When you grind a bevel a burr of deformed metal sticks up from the bevel. Simply leave that bevel on the scraper and use it. This burr is rough, works very well, but doesn't last too long until it's knocked off or worn away - then back to the grinder.
Instead of the grinder burr, I use a burnishing tool exactly like one that fine furniture makers use on a hand-held cabinet scraper. I first remove any burr from the grinder with a hone or by stropping. Then I press a round or oval burnishing rod into and draw it along the tool edge from the bottom at a slight angle which deforms the sharpest part of the edge and raises a smooth burr up from the bottom bevel. It usually doesn't take a lot of pressure. You can easily feel this sharp burnished burr with your finger or catch it with your finger nail. You can use any hardened rod as a burnishing tool, even a lathe tool like a spindle or bowl gouge. The smaller diameter the rod the less force it takes.
Here are some burnishing tools I use, made by epoxying a rod into a handle. The first is one I've used for years, shown with an extra rod - the second is one I made recently from some small rods I got from Reed Grey.
carbide_burnisher.jpg burnisher_IMG_6767.jpg burnisher-veritas.jpg
The third is a burnishing tool from Veritas. I've had it the longest but I don't use it any more. It is easy to be too aggressive with it and raise TOO much of a burr which can make the tool too aggressive in use. It is better for really big scrapers for big work.
I use the first two burnishers on cabinet scrapers and similar smaller hand-held scrapers as shown below. I have used some of these on a variety of turnings for almost as long as I've been playing with lathes.
scrapers_.jpg scraper_PB054025_s.jpg
Hope this helped! I am certainly no expert on these but this is what works for me.
JKJ
Posting Permissions
Reply With Quote