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Little Festo
10th June 2004, 12:21 PM
I have a nice heavy bowl scraper. The scraping edge only allows for scraping the inside of the bowl. I was going to put another scraping edge on the opposite edge to allow me to scrape the outside of the bowl as well. Is there any reason why I shouldn't do this? I can't see why I shouldn't. I'm new to turning so I might be missing something regarding doing this. Any advice??


Peter

Cliff Rogers
10th June 2004, 01:33 PM
G'day.

I'm confused... :confused:

What sort of a scraper is it, IE what shape?

What opposite edge?

The one below it or the one on the right side?

Little Festo
10th June 2004, 03:37 PM
I whipped up a rough image to illustrate what I meant. The Bowl Scraper has an edge as well as the end that can be used for scraping. Using the edge/side works well for the inside of bowls and I thought that it would be good for the outside of some pieces as well. The problem is that you would need to use the opposite side of the scraper wich in this case hasn't a scraping edge. I suppose I could just use the gouges as I am at present but I thought that this could be usefull for some pieces.

The scraper is a Raffern scraper by Henry Taylor (I thinK).[B]

The "Busted Bowl" hasn't led me to thinking about this as the finnishing cut that caused the catch couldn't have been carried out with a scraper anyway. For that I definatly chose the wrong tool.


Peter

Christopha
10th June 2004, 04:38 PM
Your bowls must be of quite small diameter and quite deep for that diameter to need a scaper much at all and why would you want to scrape the outside of a bowl at all? :confused:

rsser
10th June 2004, 05:12 PM
Yeah, you can (I've done it on a cheap scraper) as it also allows you to undercut on a stem too. But you lose some radius from your inside curve. (Raffan recommends a curve close to that of the bowl you're scraping). And don't sharpen too far down the off side.
Cos the overhang in scraping the outside is much less than the inside, I'd recommend you use a normal weight tool for this purpose. Get a bit of HSS from Gary Pye and make your own. Some turners scrape outside without the rest, at a 45 degree angle.
Internally, as always, you're scraping with less than half the edge, to avoid catches, and if you can tilt the tool , this shear scraping will give you a better finish (but remember to lightly round off the edge of the tool that's moving on the rest; we want smoooth movements here ;-} )
Let us know how you go,
Ern

Little Festo
10th June 2004, 05:27 PM
I've been making quite a few closed forms and a several bowls with undercut rims that have made it diffficult to get even wall thickness all the way down to the bottom of the bowl or form. The Raffen scraper does a good job in these hard to get at places and for cleaning the interior bottoms where, in both cases, tool rest support becomes a problem. The scraper feels very safe to use in those situations and does well in giving a good finnish on most of the timbers I use.

Well I guess wanting to scarpe the outside ocassionally shows my lack of experience. I've been geting smooth surfaces at the moment using a bowl gouge so there probably no need to change.

Peter

Christopha
10th June 2004, 05:34 PM
Fair call Pete, you seem to have answered your own question quite well. If you are getting a good finish from your gouge on the outside of the bowl/vessel then you are driving the gouge ok and you don't need to risk messing up the finish with a scraper. As for the interiors, their are heaps of hollowing tools and scrapers on the market, the ones that seem to work the best have their cutting edge in line with the handle no matter what shape the rest of the shaft is.... leverage I guess mate. Good luck with it.

rsser
10th June 2004, 06:23 PM
And good for you, getting a heavy bowl scraper. Nothing can match it for getting an even curve on the bottom of your bowls, and it's just an extravagant and awesome hunk of metal ;-}
Ern

powderpost
10th June 2004, 09:56 PM
Peter, yes you can scrape both inside and outside of a bowl. I do this regularly to remove the marks left by the gouge. Try shaping the end of your scraper to an elongated egg shape down both sides about an inch. I have quite a variety of scrapers that I use regularly, but only on bowls. It is important that when you scrape on the inside of the bowl, that the tool rest is on or slightly above centre, so that the cutting edge is above centre. On the outside the cutting edge must be below centre. This will almost eliminate 'catches'. If you think about this, the reason is obvious. I use a 'shear' scrape method that almost eliminates sanding.
Jim

Cliff Rogers
10th June 2004, 10:07 PM
G'day.

Subject covered....
Now get some more practice with the bowl gouge.

If I strike a problem on the outside of a bowl that looks like it will respond to a scrape better than a cut, I just roll the bowl gouge over on the rest so that the bevel is pointing away from the work & imagine that the inside of the flute is the top if the scraper &, using a LIGHT touch & keeping the top edge clear, I scrap the surface that needs it. I usually stop the work after a short scrape & see if it really is doing a better job before I proceed too far.
This technique is usually refered to as a shear scrape but that really depends on the presentation angle of the tool as to whether it is shear scraping or flat scraping.
I have a long grind on my bowl gouges & I have used this technique that often that I hardly ever reach for my scraper on a bowl now, inside or out.

Little Festo
11th June 2004, 09:29 AM
Thanks for all the advice. I haven't started using the scraper until recently. On my closed forms the lower wall near the base and the internal bottoms (?) were a bit rough and the scraper really worked well there, even without good (close to the scraping) toolrest support. The Raffern Scraper is nicely rounded and as I said earlier it really feels safe and dosen't seem to catch too easily. I'm using a articulated hollowing tool that makes it very easy to undercut the rims.

Anyway thanks again, and good turning!!


Peter