Scraping Blue?

Russ,

I do not know of any supplier to the hobby in the UK offering "good" (I define good as easy to work with) new hand scrapers. Greenwood tools offer the sandvik range which are used by professionals and hobbyists alike but they have no flex and the handle is not comfortable to position in to the stomach. (well not for me in my physical condition!). A bit of flex makes life easier. My ideal hand scraper would have the following attributes:

Mild steel construction. e.g. width 1", thickness 3/16" length to suit but approximately 18" with a tang for a file handle or similar. Clamp on the business end to take the standard BIAX style "carbide tipped mild steel blades".

You can buy the blades or make them from mild steel based on the BIAX type::

Length: 150mm, Width 20mm, thickness 2.5mm.

Short 80mm long, width 20mm, thickness 2.5mm

You then have a bit of carbide brazed in at the business end that you grind a radius profile and rake on.

I use a long blade (which give you more flex over the whole assembly) for scraping for flatness. Scrape to within 0.001" or better flatness. Then I switch to the shorter blade (as I get more positioning control) for scraping for bearing.

I wrap a tennis racket grip over the part of the scraper that I grip with my hands. This stops me getting too tired in the hands too quickly. I have put an angle grinder flap wheel rubber disk in at the file handle end. This spreads the load across my stomach. I've seen others turn a nice stomach support from wood or plastic. The angle grinder plastic wheel is perfectly fine for me. Without it scraping hurts my stomach!

I am pretty sure the average model engineer could knock up such a design in a short while for not much outlay. Perhaps this is why no one stocks them. If e.g. Arc stocked them I am sure they would sell plenty of blades. I have a fair few with different radius and rake ground on them and some with an angled grind to facilitate getting in to a dovetail.

I'll get a couple of pictures taken and post them later.

Thanks,

Steve

@Steve,

What radiuses of scrapers are you finding most useful?

Martin if you're starting out you should go for a 6omm radius scraper or smaller. Anything more and you risk gouging the part with the corner of the blade. If you're scraping small ways use 40mm or even down to 20mm so your scrapes are smaller in width.

If you guys want to make a scraper for yourself you could take my approach. I just made a bunch of them for the scraping class we held last week and knocked up some handles from wooden curtain rail dowel I got at the boot fair. The cost for batches of 10 scraper handles was about £3 a pop. Buy the metal from Tilgear 25x3mm cold rolled steel.

http://www.practicalmachinist.com/vb/machine-reconditioning-scraping-and-inspection/beginner-scraping-question-scraper-design-343434/index3.html#post3089226

These were very popular at the class and most of them were taken away by the students, I managed to keep a handful for myself.

Edited By Pete Rimmer on 17/12/2017 12:44:34

When I started my apprenticeship as a fitter too many years ago, one of the first tasks was to make a set of scrapers out of old files. I still have 2 of mine and they are still useful.

I've always found carbide ones to be inferior.

Brian

Carbide needs a different sharpening technique to high carbon/high speed steel. Can't say that I ever heard anyone else call them inferior, perhaps the file might suit your scraping technique better. My HSS scraper need sharpening a lot more frequently for sure.

I too made scrapers from old files and still have them. I even ground the teeth off on the surface grinder. I also prefer them to the sandvic carbide scrapers.

Brian

Sandik scrapers are gash. One of the guys at the class brought a brand new one, tried one of mine and put his Sandvik insert in it for the rest of the week.

Snap! Didn't think anyone else would remember making their own scrapers, chisels...

​George.

There must still be a use for Micrometer Blue as you can still buy it in many places?

I made my internal scraper from a file as an apprentice piece in my first year, 51 years ago, still usable.

I use it quite often. It has a very dark pigment which means it's easier to see when it's rolled out thin. I'd use it all the time except for the fact that it's oil-based and doesn't come out of your skin too easily.

Takes three seconds to put on and three weeks to clean all the surfaces in the workshop after use.

Regards Ian.

Andrew, sent you a PM

Simon