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Using a moulding scraper tool?


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Hi Al,

You're probably trying too hard.  These tools are relatively slow workers but they can do a good job.   These purchased tools per se, which I have never used (just file my own in some scrap from a tin can or old razor blade),  are probably sharp enough but just make sure.  Rub the flat side on a stone or some very fine wet or dry sandpaper if needed.  Then hold the tool a a 45 deg or so angle and work slowly, not trying for too much of a cut at once.

 

Chazz

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3 minutes ago, Chazz said:

Hi Al,

You're probably trying too hard.  These tools are relatively slow workers but they can do a good job.   These purchased tools per se, which I have never used (just file my own in some scrap from a tin can or old razor blade),  are probably sharp enough but just make sure.  Rub the flat side on a stone or some very fine wet or dry sandpaper if needed.  Then hold the tool a a 45 deg or so angle and work slowly, not trying for too much of a cut at once.

 

Chazz

Thanks Chazz. I'll try your tips when I get back to the shop tomorrow morning.

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If the edge is sharp, a 15 degree angle should be sufficient. As mentioned, many light strokes are far more effective then pressing down. If you do that the tool will either chatter or dig in. Also. be aware of grain direction: sometimes pushing the tool rather than pulling is more effective.

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3 minutes ago, druxey said:

If the edge is sharp, a 15 degree angle should be sufficient. As mentioned, many light strokes are far more effective then pressing down. If you do that the tool will either chatter or dig in. Also. be aware of grain direction: sometimes pushing the tool rather than pulling is more effective.

I was for sure applying pressure. Probably too much.

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Al,

One other thing.  I know this is very obvious but just to make sure the strip of wood you are trying to shape is the width of the profile.  If not then it will wander since the sides cant keep it within the profile shape. (see pic below)

 

I know you are probably already doing this, but just stating the obvious.

 

Like Chazz and Druxey said, the edge should be sharp and light strokes.  I personally recycle my xacto blades (which I have plenty).  Cut the profile you want with a file or my personal fav...abrasive Dremel wheel, and I have nice control since it is in the xacto handle.

 

 

InkedScraper_LI.jpg.17da5aa6638efa849d35bdf922f27bab.jpg

 

 

 

 

Edited by Dowmer
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Ah, it seems to me that there is a fundamental problem with these scrapers.  While they may be quite sharp when they come from manufacturer, I don't see a practical way to resharpen them to a keen edge.

 

>The cutting action of a scraper is achieved by a tiny burr on the edge of the steel<, and over time the burr is abraded away by the scraping action on the wood. 

 

A cabinetmaker uses scrapers of relatively simple shapes - a straight edge or a broad curve.  The process of sharpening these scrapers is to file the edge flat (i.e. 90d to the broad planar surface of the scraper), and then draw a burr on the filed edge with a hard steel burnisher (e.g. a screwdriver shaft or router bit) at about a 5-15d angle.  

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While I agree with Bob's comments on cabinet scrapers operating with a burred edge, the right angled edge on a small profiling cutter works just fine. It would be impossible to burr over such a small and complex shape. The moldings shown were all formed using a broken hacksaw blade for the scraper metal. The model is at 1:48 scale.

C stern complete 14.6.jpg

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Absolutely beautiful Druxey. A true work of art. I'm going to try making my own scraper tomorrow. The factory made ones I have are the wrong size for my application and they do drift. I'll be carving my own decorations (very simple compaired to yours) and your work is an inspiration for sure.

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I have the micro scrapers and after a little practice I found that the basswood that a lot of models come with seems to be too soft. I used pear wood and held the scraper straight up at 90 degrees and they worked great. These micro scrapers don't have a burr edge so holding at an angle didn't work at all for me. Straight up worked best for me.

Edited by Burroak
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Druxey - fine work there.  I do think the profiled microscrapers will work for a time - the duration is determined by the metal's qualities and the nature of the wood.  

 

Hacksaw and reciprocating saw blades are excellent material for making small cutting tools.  With a small butane torch, they can be annealed for shaping with file and grindstone, and then rehardened and tempered for use.

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Thank you all for your help and great suggestions. I just finished making 2 moulding strips out of Swiss Pear and have them soaking in water to be bent to shape. The home made tool cut really well as you can see from the shavings in the picture. The diamond cutter had no trouble cutting the blade using the fastest speed on the Dremel tool.

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1 hour ago, dvm27 said:

I do have a complete set of those Micro Shapers and find the profiles too large for most of the moldings I need at 1:48 scale.

Yes they are. I think they are too big for most ship modeling applications. Now that I did it its really easy to make your own. I think I remember seeing Chuck make a scraper from brass. I'm going to try that next time. That way it can be done with files with more control.

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2 minutes ago, druxey said:

It has to be heated to cherry red first to soften it, and allowed to air-cool. This process is called tempering. Then the metal can be filed or ground. To re-harden it, heat it again and quench it in oil.

I’ll try that. 

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Y.T.,

One reason you can't file a smooth form is that even the finer files have teeth that are separated by most of half a millimeter and catch on the thin edge of your workpiece.  Try  a fine diamond file.

 

An alternative is to use a tiny Dremel rotary bit. Because the bit rotates more or less in line with the workpiece, it won't catch as much'

 

However, I think you'll have a lot of trouble making a strip as small as half a millimeter.  I'd use a flat edge of a scraper and a piece of your 1 mm stock and just cut it down.   If you have a couple  of pieces of metal of the right thickness. lay the strip between them to control the depth of cut.   For something as small as this, precision of cut is all important.

 

Chazz

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20 hours ago, alde said:

A cheaper alternative that may work is guitar nut slotting files. I didn't think of it until your post but I have a full set and they go pretty small. 

Have you tried jeweler's saw blades in a saw frame?

 

Guitar files might work.  But I haven't used them when slotting bone nuts for strings on guitars.  What I've done is to dip a short length guitar string of the desired size in automotive valve grinding compound and saw the bone with that. I can also clamp the string in a jeweler's saw.

 

http://www.rings-things.com/Products/Tool-Saw-Frame-4-Swiss.html?gclid=CjwKCAjwhqXbBRAREiwAucoo-xVMV0WS0RNOCEnUAFj5QGfyun2ghCMzrhB4zECZZCzKsY_SbVY0VRoC73sQAvD_BwE
 

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Y.T.,

 

I'm not good at adding sketches at midnight.

 

Just take two strips of some material of the right thickness, like brass shims,  1/2 mm. thick in this case, lay them side by side on your work surface to act as a depth gauge, hold your work piece close between them and scrape it down with a flat edge such as an Xacto blade or single edge razor blade, With the 1 mm. strip you already it should be  easy work. Sandpaper might also work.

The brass (or other strips of material) are guides to keep from going too deep as well as support the work both flat and side to side.The biggest problem in working with thin strips like these is breakage since they have such little strength.

 

Chazz

Edited by Chazz
clarity
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12 hours ago, Y.T. said:

Hi Bob Blarney, how wide cut does jeweler's saw blade?

Here's a chart of blade thicknesses- the kerf will usually be a little bit wider than the blade.

 

https://www.gesswein.com/p-12889-super-pike-swiss-saw-blades-gross.aspx

 

Here's a vendor of blades in the US (Michigan)

 

http://www.crhill.com/pikesawblades.aspx

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4 hours ago, Y.T. said:

Chazz. This sounds good 👍 Only issue might be how to securely clamp a wood piece so it does not shift around when I work on it. I believe I will figure this out. So far this seems to be best solution for my issue. I even might be using 0.5 x 5 mm wood strips to get 0.5 x 0.5 mm squares for my windows.

A length of double-stick tape will hold the wood in place for 'planing'.   Alternatively, glue one end of the stock (~1 inch longer than needed)  to a backer board, and then cut off the needed length after thicknessing.  

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14 minutes ago, Y.T. said:

 

Hey Bob Blarney - all great ideas! Thanks a lot!

Hmm, have a look at this prototype of a saw based on the chevalet concept.  So far as I know, it's not in production yet at Knew Concepts (which makes outstanding saw frames for jewelry and woodworking).  Btw, the author of the blog is Don Williams, who is an expert conservator and has worked at the Smithsonian.

 

http://donsbarn.com/report-from-wia-a-silent-clap-of-thunder/

 

http://www.knewconcepts.com/index.php

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