Scraper from a File

[ejcrist]

I made a scraper from a mill file and want to put a 90 degree bend in it. I tried heating the point I want to bend with a propane torch in an attempt to get it cherry red but didn't have any luck. Is a propane torch with a standard pencil tip hot enough or should I use mapp gas?

[DougGuy]

It needs to be cherry red if not orange. Mapp would do it but files are really hard and it may just break even after it cools.

[oger]

Never tried to bend one but a cutting torch will get hot enough. Cooling must be controlled at the very least and probably some sort of stress relieve will be needed. I made one without a bend 40 years ago and it still works just fine.

[ejcrist]

Ok I'll give mapp a try. I've been just letting it air cool; from what another fellow said on here it'll end up softer than the original hardness unless I quench it. After it cools I'm planning on tempering the cutting edge by heating it to straw and letting it air cool again. I have no idea what I'm doing but I've been having more fun playing with this file than working on the flintlock I'm putting together.

[firebrick43]

When you say scraper are you talkin a wood scraper or metal scraper? Either way, yes to a mapp torch, even it may have issues depending on thickness.

A oxy acetylene torch will work much better.

Letting it air cool anneals it. A wood scraper may work like this but would much better if quenched and tempered. Tempering has no value whatsoever unless you quench first.

[calaloo]

To anneal the steel it needs to cool very slowly. Heat the part cherry red and bury in fine wood ashes or lime. It will take a long time to cool. The file should be ground very smooth where the bend will be. If there is a place for a crack to start it will crack.

[AJB]

I have a lot of chisels made from old files that were passed down to me from my grandfather and they work great. However, for bent scrapers I have had success making them from spade drills. I select a spade drill that is the width I want, grind it the contour I'm looking for, put a fine edge on it then clamp the spade section in a vice. I then heat the shaft section next to the spade with a propane torch and bend it to the angle desired, usually about 45 degrees. The shaft can then be cut to length and a file handle is attached to complete the project. I'm no expert, but sharpening is the key to a scraper working properly. Basically, they seem to work best when sharpened razor sharp then the edge must be "rolled" with a burnisher in the direction that the tool will be pulled. When done properly, you get shavings. Without rolling the edge, you get something that looks like sawdust.

[Hooker53]

Mapp is just bearly enough depending on how thick your file is. Like was stated above, SLOOOOW cooling to anneal. Depending on the heat involved, 90 WT gear oil is good for tempering.

While we at it, a neet three corner scraper can be made from a three corner file. We use to make one from them for use in lathes years go until they came out with them and later small diff size/shape cutters that quick change in and out of a handle. Let us know how it turned out.

Roy
Hooker53

[leebuilder]

You may be loosing all your heat, try some bricks to make a corner type thingy to put the file tip in and then heat. Mapp would be better. Got to get then cherry to orange, Plus 1 on that. I made one out of an old lawn mower blade. Thinking now can you thin the file down? To make it thiner.
be safe.

[Von Gruff]

I have a few and they are hard to beat for inlet work but I did nothing more complicated that grind the teeth off, heat them with oxy acetylene, bend them and drop them in vegetable oil. They work very well indeed

[ejcrist]

Thanks for all the info fella's. I got a map kit for $49 over at Homeless Depot and put her to work this morning. The mapp worked exceptionally well. Got the file section to cherry red in about a minute and bent to the shape I wanted. This scraper is for wood; a barrel channel scraper in the shape of an octagon cut to the smallest portion of a swamped barrel. I still need to temper it yet, and based on what I've learned from here so far it sounds like heating the scraping part up to cherry and then quenching in oil to cool, and then heating again until straw colored and let air cool will do the trick. Once again, thanks for all the info.

[AJB]

As a follow up to my earlier post, this is a pic of a scraper made from a spade drill with a file handle attached. It works pretty darned well.

[fast ronnie]

I made one from a 1" wide piece of .030 spring steel left over from a job. About 6" inches long and put a different radius on each end. It worked really well for the barrel channel and left a really smooth finish.