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Carbide Hand Scraper DIY

FJsapper

Cast Iron
Joined
Nov 18, 2020
Location
Sterling Heights, MI
Got some really good info here from several different threads so i thought i would compile what i learned and applied to produce my hand scraper.

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I recently made myself a carbide hand scraper in order to work through a lathe rebuild i am working on.

https://www.practicalmachinist.com/...d-metalmaster-384378-post3660895/#post3660895

Anyways i pretty quickly realized hand scrapers are expensive to purchase and may not be as well suited to individual needs from the factory based on individual height/arm length etc. I am a tall dude at 6'3" so i decided to roll my own.

The last post of this thread by Richard King sealed the deal for me. Synopsis: make your own scraper for like $30. https://www.practicalmachinist.com/...here-buy-hand-held-scraper-328552/index2.html

I used nothing but the most basic hand tools and a bench grinder. I purchased 36" of 3/4"x1/8" 1018 steel bar stock McMaster-Carr. The handle was made from a scrap piece of walnut and a junk bronze bushing and taper pin.

Once i had the metal i used the bench grinder to roughly profile a .35" circular cutout 1/16" through the thickness of the 1/8" bar. A hand file was used to square the cut off.

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Then i cut a nub off the end to use as the top cap for the scraper.

3/4"x3/4" square carbide blanks were purchased off of ebay for 25x @ roughl7 $28 shipped. Far cheaper than you can find new.


These were then profiled and sharpened on the diamond sharpening plates i got off of amazon. 1x @ 400 grit and 1x @ 1000 grit. I have a 3000 grit on the way but for my current needs that is good enough.


On the grinder i made myself a rest on each side @ 5deg out of 2x4 lumber i had laying around. Please keep in mind i used an extremely ancient and secret method to obtain the requisite 5deg angle. On the 1/8" blades i put two bevels on each side each at 5deg.

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Holes were drilled and the two pieces were assembled to sandwich the carbide. I tapped 10x32 holes and used 1/4" hex screws.

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And from there i was able to shred paint and metal as needed. Total cost was less than $35 and 2 hours time.

This is totally within the capability of the shop that has no access to a drill press, mill, lathe, or pretty much anything else you could imagine as necessary for precision work.

Thanks everyone for the great threads that allowed me to figure all this out. Hopefully consolidating this in one place is helpful to someone else.
 
Nice job! The time you invest in making good sharpening tools for your scraper will pay off many times over in better and faster scraping work.

If you spend another hour at it, you can make a jig that lets you control the radius on the end of the blade. Just take a strip of wood 8-10 inches long and 2-3 inches wide. Make a slot in it in the center of the long direction that your scraper drops into. With some T-nuts and scrapwood or similar make a clamp that holds the scraper into the wooden strip. Then drill a sequence of 1/4" holes down the middle of the strip on the bottom side. Make a hinge with a 1/4-20 screw in another piece of wood, that you can clamp to the table by your grinder. Now you can grind a controlled radius on the carbide!

Here's mine:
https://www.practicalmachinist.com/...ml?highlight=radius+scraper+blade#post3111305
 
Thanks FJ.... It is pretty simple to make them. Keith Rucker copied a new BIAX hand scraper and did a drawing on a PDF link. He then made 10 to pass out for the first scraping class he hosted. He later told me, he wished he had told all to buy one from Dapra. I think the 10 was the challenge not making just one like you did. I have some comments and I'll write them after I tell Ballen something.

Bruce Writing the help / teaching on your Studer was fun...very satisfying to be able teach you over the net. It was easy because your a perfectionist and very talented Engineer and teaching in your own right.

Now back to the hand scraper and lapper.... I'm going to tweak them because I love what you did, but I'll try to improve them a bit. Happy New Year by the way to all.

The wood handle pad looks to long and heavy to me. Not the metal bar. I'm 6'3" and prefer longer scrapers but some shorter people may prefer shorted ones too. That's why some should experiment with the length. Here is an experiment you can make. hold the metal handle with the 2 hands as I teach. hold the rear placement of your hand.
I am right handed so I place my right hand on the back side near the middle of the scraper, hold it like you hold your fishing pole or a golf club, thumb up on top. Then I place my left hand approximately 1 1/2" from the tip of your right hand thumb with my left thumb laying on top of it and fingers wrapped around the bottom of the metal handle. Hold the scraper lightly against the hip bend over forward like your going to scrape a part.

Then lightly release your grip, Does the wood handle drop and the metal handle pivot ? back down and front up?? If the wood drops then I would make it a bit shorter to get the right balance. You may want to wrape some electrical tape around the metal too. Some cut a 6" length of rubber coolant hose and slide it up the metal for a cushion.

On your lapper I would place the wood block in front of the center bolt. Them make your block so the 5 deg. slopes down toward the wheel. Higher in back. That way when you spray on your lubricant on the wheel and as you lap, you can see the lube peal off the top of the blade. Then you will know the angle is the same all along the blade radius. I hope this helps and I explained it OK. Rich
 
Some pics of some scrapers. I had a student in Maryland who took the class at Tuckahoe Steam and Gass Association Machine Shop Museum hosted by our member Paloe (hope I didn't botch his name to bad) Anyhow the one student used plastic conduit one size over the other so he could regulate the length. It was a pretty good idea, but it didn't work to hot for me. He slid in a short metal clamp on one end to hold the insert.
Pic. L to R. Student holding scrape, check out how he is positioned , eyes above work. Jim at Augusta GA class bump scraping, I would have preferred he had his fingers touching the yellow sanding disk pad. I was scraping a small Swiss screw machine slide vertical with hand held differently, My scraper, I use a black rubber sanding dish screwed to the end and a German scraper hand using a short scraper without a pad look at how he is standing and pushing with his body and not just his arms.
 

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