custom molding profiles, how?

See my response under Messages

Dick Schafer

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small custom mouldings = scratch stock

paul womack

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scratching problems, need advice

bill tindall

>While I can sharpen a card scraper with reliable success, there is clearly a defect in my approach to scratching. It looks, well, like scratching! When I have attempted it on simple beads (typically walnut) I get fuzzy surfaces and it is oh so slow. My daughter's cat has made better profiles on her table legs.

The thought of scratching a 3/8" Roman ogee is to daunting to attempt, given my bead experience. I suspect the problem must be my preparation of the cutting edge. So, what does one do after filing the desired profile, say for example, with a round chain saw file?

I took a class (Bird) that might have given me some insight into scratching but the inflexible syllabus did not allow any insight to be gained and it was a wasted day and $100.

I'm no help but...

Scott Burr in Ben Lomond CA

>Thanks for the laugh Bill!

"My daughter's cat has made better profiles on her table legs."

Great line...

Re: scratching problems, need advice

Tony - Memphis

>Seems like I recall a conversation about the class!

I tried scratching a small bead on a table top mirror stand I made for the wife. The router bead would have made the quirk way too big (correct term - quirk?). I made my scratcher out of a piece of small scraper stock from Lee Valley. I ground about a 1/8" bead in it. The handle was very crude. I polished both sides of the scraper fairly well, so the edges were pretty sharp. It worked surprisingly well. I was very pleased with the result. I think there have been some articles in FWW on scratch stock stuff. Matter of fact, I think Garret Wade has a short video online at FWW, or used to anyway. He even discussed hardening for long term usage.

Tony

Re: scratching problems, need advice

dave j

>Bill,

I must state up front that I have not done any large profile work I have had some success with small scratch stocks. Like you mentioned, getting them sharp is the key. I have made mine from .062 and even .125 thick O-1 which is quite easy to file and shape while soft. Get it as close as you possible can with a very fine edge before you harden and temper. I have had pretty good success with the profile being shaped at 90 degrees to the face of the "blade" but the edges need to be dead sharp. I have used a thick block of wood in a vise as a guide to help me keep the file at 90 degrees. Flatten/polish both faces like a plane iron. the stock only needs to be held a few degrees off perpendicular. Your holder should have a fence that allows you to rotate the stock as needed. I also have a KCTW windsor beader which is fun to use, but again, I have never done large scale stuff.

Exactly

Jim Reed @ Tallahassee

>my experience. I use my #66 frequently. Just make sure your scratch blade is a sharp 90 degrees. Also try not to be too aggressive--steady and even scratching will wear down the fuzziest of wood.

Re: scratching problems, need advice *LINK*

paul womack

>When I have attempted it on simple beads (typically walnut) I get fuzzy surfaces and it is oh so slow.

Clearly a blunt cutter.

You want the filed (narrow) surface at 90 degrees - any convexity is clearly bad, so file carefully.

*if* you can, follow the file with either sharpening slips or SiC wrapped around anything convenient to refine the surface. Again be very careful to stay at 90 degrees.

Finally, to ensure the arris is as sharp as possible, polish the flat faces of the cutter (at least at the business end).

A 90 degree cutting is quite robust - I see no need for hardening and tempering. If you're using a scratch stock cutter enough to require these processes - you should be using a plane!

I use old saw blades for cutters, from a big old defunct rip (slightly thicker stock than smaller saws).

Since even a good scratch stock removes wood very poorly compared to a true blade, remove as much waste as possible first, with jacks/ploughs/rabbets/rounds depending on what you have.

BugBear


http://www.geocities.com/plybench/scratch.html

thanks for useful suggestions

bill tindall

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