Using a moulding scraper tool?

[Bob Blarney]

 "...dip a short length guitar string of the desired size in automotive valve grinding compound..."

 

It occurred to me that this method works with bone, because I can wash off the oil-vehicle that carries the grit of the valve grinding compound.  This would be a problem with wood.  Maybe lapping/polishing powder can be used  - an alternative would be to dip the wire string in glue and then dip it in the powder and let it dry to make a fine abrasive saw.  

[alde]

I dug out my guitar but slotting files for the heck of it. My smallest is .010” and the largest is .056”. They should work just fine if the metal is softened first. Here are a couple of pictures.  The cutting surface is on the edge.

[druxey]

My watchmakers' screw slotting files go down to a little under 0.010" wide. Unlike fret files, they cut a square bottom slot. Jewellers' saw blades are a good and cheaper alternative!

Edited August 9, 2018 by druxey

[NGCathey]

On ‎8‎/‎8‎/‎2018 at 6:38 PM, druxey said:

My watchmakers' screw slotting files go down to a little under 0.010" wide. Unlike fret files, they cut a square bottom slot. Jewellers' saw blades are a good and cheaper alternative!

I have always wondered how the small shapes were made.  Do you have a good source of this watchmaker's screw slotting files>

 

Thanks.

[druxey]

Either the Internet or possibly a company like Contenti.

[NGCathey]

Thanks

[wefalck]

For very fine profiles I use a piece of razor-blade held in a pin-vice:

 

The radius of the above profile is 0.2 mm, giving a 0.4 mm half-round profile. When using scrapers for this purpose, it is important that the stock is as close to the finished dimensions as possible. You really only want to take the edges of the material. It may be necessary to use a couple of differently shaped scrapers in sequence to arrive at the final profile. The scraper will have to be held almost vertical to the intended profile. Any angle will distort the profile, it will become shallower and semi-circles will become oval. This is one of the reasons why only minute amounts of materials can be taken off at each pass.

 

It may be obvious, but one needs to pay attention to the wood-grain. If it runs at a slight angle to your stock, you can only scrape with the grain and not against it. If you try the latter, the surface will be ragged, as the scraper digs in.

[Moab]

Thanx for that solution Wefalck. I agree that placing the shape in a pin-vice sounds like a great idea and I'll try it soon. The pin-vice will add some stability to the scrapper which will keep it more ridged. It limits the shape size but I'm sure similar solutions can be found. I've learned that "practice makes perfect" and that certainly applies to me when learning to use a scrapper...Moab

[wefalck]

Don’t have that much experience on wood, used this scraper on Plexiglas. However, dense wood with little pronounced grain, such as box, pear, or cherry seems to work best. Ideally, the grain should run along the batten. If it is slightly oblique, never scrape against the raising grain, or the scraper will dig in. As the name says, you scrape, you don’t really cut - unlike with a plane. Repeated light touches are the ‚secret‘.

[Larry Cowden]

Who is Y.T.? And how do I find him? I am hearing good things and references to him.  But every search on this site is a zero!

[mtaylor]

19 hours ago, Larry Cowden said:

Who is Y.T.? And how do I find him? I am hearing good things and references to him.  But every search on this site is a zero!

Y.T. is a former member banned for promoting kit piracy.  

[Charles Green]

Cutting the contour in the edge of a razor blade and using many light strokes with the blade at 0 to 15 degrees (as many have recommended)  has worked for me.  Straight-grain box or pear work very well. 

 

The Dremel abrasive disks may be too wide for some profiles.  Dedeco supplies the dental trade.  They sell disks as narrow as 0.005 inch.  Don't even chuck one of these up without eye protection!

[Larry Cowden]

On 8/8/2018 at 11:11 AM, Bob Blarney said:

Hmm, I've sometimes wondered if a (miniature?) chevalet would be useful for modeling:

 

 

The Chevalet appears to be nothing than a scroll saw turned on its side. So I don't see much advantage to it except for sore muscles!