Looking for some scraping tooling tips

[macardoso]

OK, I've dabbled in scraping a bit and have watched more hours of video on the subject than I care to admit, but the seemingly high barrier to entry (in terms of tooling) has kept me from getting serious about trying to learn. The small amount of scraping I have done has been rather successful in terms of accuracy, but terribly slow. I am currently using a file with the front ground into a scraping blade.

What I do have:

• 18x24" surface plate, grade B
• Dial test indicators, 0.0005" and 0.0001"
• Dial indicators (0.0005" and 0.0001"
• Dykem Hi Spot Blue
• Several files ground for scraping
• Crappy bench grinder with coarse wheels

My file scrapers work, but the relatively rough ground edge leaves a scratched cut rather than those shiny crescents you see people doing on YouTube. I also have difficult with removing any substantial quantity of material. I know scraping is slow but I bet I'm working at 1/10 speed with the file. It just doesn't want to bite.

So I started looking at scrapers. I see two options easily accessible to me: Sandvik scrapers through MSC and Anderson tubular scrapers. Both are about $100. OK, a lot of money for a metal stick but it will last a lifetime so I can deal with it. I have heard mixed thoughts about both due to their relative stiffness. I have also seen some shop made scraper plans floating around, although I can't remember where. If it takes me more than a few days to make the scraper myself, I'd rather just buy one. With work and family and other shop projects, I don't have the time I want to spend on it. I've checked eBay, but scrapers there are few and far between with prices almost that of a new one.

Next up, my file scrapers dull fast, and while HSS would be way better, I do see the draw to carbide scraper blades. First off, holy moly, $50 a blade on eBay sure seems like a ripoff, but maybe that's how much they run. Again, if it gets me going, the price is fine. But now you need to be able to sharpen carbide. Don't think a green wheel will cut it so now I have to find or build a slow speed lapping disc. Again not an impossible task but the cost and barrier to entry grows.

Any tips? What is a good scraper to start with. Are the prices I'm seeing just market value? Anyone have a used one they want to part with? Do you need a separate tool for flaking? I would imagine a Biax would be absolutely overkill for a hobby guy unless an eBay steal came my way.

So next to marking compounds. Hi Spot Blue seems to work OK, but it goes on very heavy and within an hour it is dry and barely transferring at all. Great for later stages of scraping but not at the beginning when you actually want to see your blue. What works better?

What other measuring tooling is needed? I've seen those scraping flats (steel disc that bridges across your high points) but don't know what they are called or where to find them.

Any tips on learning resources. At this point in time, I have neither the money nor time to attend a scraping class, but I'm all for video instruction. Have no issue biting it off and trying to learn more myself. This is all a hobby, but I do identify it as a useful skill to know.

 

[hwelecrepair]

I have only scraped one machine in, my WB Knight #2, and I absolutely hated it. I was blessed to have 3 guys who scrape for a living to guide me through the process. I am not sure I would want to learn it without someone there to explain why I am doing it wrong and what causes it.

I am sure King will know more of how to do distance learning/teaching.

 

[Braeden P]

i used a wood lathe on slow speed with cheap diamond wheels on a threaded rod worked fine for me i just used a tormek table as a rest but they are easy to make if your birthday is soon ask for a scraper i did for Christmas and i got a Anderson.

 

[Liljoebrshooter]

I bought the Sandvik. I was going to build one also and changed my mind. It is nice. I also bought another carbide insert on e bay. I am not sorry for spending the money on it.
Joe

 

[benmychree]

I have both Anderson and Sandvik hand scrapers; I think the Anderson is a POS. I have had the Sandvik for about 55 years and have used it quite a lot and sharpen it in a diamond wheel on a Baldor grinder, Glendo gives better finish, but the Baldor does a good enough job. I started out with a homemade scraper made with a file with the teeth surface ground off on both the faces and sides, then forged the end down to a thin point, ground it smooth and re hardened it, and finished the point with a India stone; it worked well, but needed frequent re sharpening with the stone.
I now mostly use the Biax scrapers, except for small dovetails.

 

[Rex Walters]

I highly recommend the Dapra design for a hand scraper because you can move blades between a Biax power scraper and your handscraper (if you eventually acquire a power scraper): https://www.dapra.com/biax/universal-hand-scraper

The scraper body itself is a simple enough thing to make. There are dimensioned drawings floating around. The carbide blades do get spendy and used ones are getting rare, as you noticed. If you only get one, you want a 20-150 or 25-150 blade. It will definitely last a lifetime.

A green wheel should be able to shape carbide, but if you can find a real Biax blade it should already have a decent curve. It is possible to hone by hand if you're patient (but you'll want to build or buy a diamond wheel grinder like a Glendo eventually). You'll need a (cheap for once) diamond stone and a jig to hold the blade at a 5-degree angle to hone it (a beveled hunk of 2x4 would suffice).

They no longer make Glendo Accu-finish grinders any more, sadly. The company is still around, though, and sells stuff for engravers. They still sell the wheels and a similar grinder for engravers without the fence and table fixture (https://grs.com/product-category/products/tool-sharpening/grs-apex-sharpening/). They are very expensive, unfortunately (which is why they no longer sell the Accu-finish grinder - no buyers for what they cost). I don't see even any old ones on ebay at any price right now.

I still use hi-spot blue, but the cool kids are using water-based printer's inks these days (Charbonnel is the brand I"ve seen). Dapra also sells water-based spotting ink.

As for what other measuring tools are required: all of them.

 

[benmychree]

The marking mediums that Rich King uses are quite good, and what Rex says above is good advice. Scraping inserts that are wider than recommended can be bought considerably cheaper than the most desirable and be cut down in width. For years, I used red lead as a marking medium, it works just fine, but don't lick your fingers.

 

[Rex Walters]

I am not sure I would want to learn it without someone there to explain why I am doing it wrong and what causes it.

Yeah, this is exactly why Richard King's classes are so valuable if you can attend one. Scraping something flat isn't that hard of a skill to learn (about the same as learning to grind an HSS lathe tool by hand) but it takes a while to figure out how to do it, how to diagnose what's going on, and how to correct problems. The learning curve is dramatically reduced if you can spend time with someone that already has the skill (true of many things).

Learning how to scrape something flat to a high tolerance is easy. Learning how to rebuild and align machine tools is a whole 'nother story. The best book on the subject is Connelly's Machine Tool Reconditioning available from Dapra. It will put you to sleep, though, and some of the content is questionable (Rich says nobody really used the water-based leveling techniques that are described, for example). It's still the best overall reference for the principles involved, though.

The marking mediums that Rich King uses are quite good

I think Rich still uses Canode water-based spotting medium, but he also likes the Charbonnel stuff. I notice that Dapra no longer calls it Canode, they seem to have their own brand on their water-based inks now. I know the last bottle of Canode I bought from them had bits of grit in it (the last thing you want when marking up!). Rich said it was just a bad manufacturing run and not foreign media, but I've not tried a mortar and pestle or heat to get rid of it.

 

[benmychree]

The possibility of grit contamination is why we spread it with out with our fingers, we will sense its presence and eliminate it.

 

[Rex Walters]

The possibility of grit contamination is why we spread it with out with our fingers, we will sense its presence and eliminate it.

Heh. If it was just a few chunks of dust or swarf I'd agree with you, John, but the batch I got was mostly grit. It was like someone had mixed a handful of sand into the ink.

It's not a foreign contaminant, though, it's something in the recipe that either crystallized or clumped up for some reason, or the stuff was never manufactured correctly originally (unsure which). If I take a small amount and mash it up good and keep stirring, it eventually seems to go away (hence the mortar and pestle comment). The individual grains almost look like glass shards (they aren't sharp, though). Never had a problem with hi-spot blue or Charbonnel, though.