First scraping attempt: a Denis Foster 8” Featherweight straightedge

Looks good and some super photo's. The close up of the blade must be the 400 grit wheel? The lines on the blade tip will leave scratches if that's the 1000 grit. I would also break the sharp corners of the blade and make a 20 mm 40 mm radius tooo. That design is a copy of Stefan Gottswinter lapper? Also my friends in Austria have a lapper the designed with a special wheel with 2 diamond surfaces on one side, a 260 and 1200, theirs also has a vacuum too as the powered carbide grit is dangerous.
 

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Richard King 2 said:
Looks good and some super photo's. The close up of the blade must be the 400 grit wheel? The lines on the blade tip will leave scratches if that's the 1000 grit. I would also break the sharp corners of the blade and make a 20 mm 40 mm radius tooo. That design is a copy of Stefan Gottswinter lapper? Also my friends in Austria have a lapper the designed with a special wheel with 2 diamond surfaces on one side, theirs also has a vacuum too as the powered carbide grit is dangerous.
Click to expand...

Yay! I’m on the right track!

Yes, the closeup is 400 grit diamond. The 1000 grit cleans those up better. I knocked my jig together pretty quick; I wasn’t sure if I was barking up the right tree at all. Now that I know I’m in the right neighborhood, I think I’ll do another more careful version with more radii (such as the tighter ones you suggest, more for the finishing stages, right?)

Thanks for the safety tip on the carbide and diamond dust extraction. I did notice later in the evening at bedtime I could taste grinder dust I will rig up a shop vac dust extractor for my setup and wear a respirator.

Slowly getting better manipulating the scraper. I keep devolving to using my arms, recognizing it when they get tired and my back starts hurting. Trying really hard to use body strokes for this roughing and early phase scraping as described in your videos and the Machine Tool Reconditioning book.

Latest progress below. Still roughing and a bit heavy on the canode blue I think. Working on finding the balance between not printing and over printing.

Thanks for your replies here, it’s extremely motivating to hear from you!

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You need to tip scrape that SE...In the picture Leave the top alone, as you have coverage all along the top. Take a black magic marker and black out the top 1/4" of the bluing, then lightly scape toward the bottom scraping a bit deeper as you go toward the bottom. Sat start with 3 pounds pressure for about 1/2 inch and then the next 1/2 inch press down 6 pounds and at the bottom right bluing press down 8 pounds. Use a bathroom scale to measure. The secret to body scraping is to pull the scraper into your body with your arms and then push with you body. Since I made the DVD I invented the term "Tap Tap" Thats the sound the scraper makes as you push forward and down and lift very fast. A scoop motion and not more then 1/4". The blade should not be more then 1/8" above the surface. You have a sanding pad on the end of the scraper right? Another thing that helps shorter people is to use a shorter blade. The Biax # 15, radius 40 mm works good. That blade is a bit stiffer and is 3" long the blade is 1/2 wide at the tip. https://www.dapra.com/biax/scraper-blades
 
You also are not scraping wide enough scrapes. That can be done by not pushing done enough. 8 pounds is the pressure I use all the time unless I do the tip scraping. Do you have a scrap CI part you can practice on? Practice on something, so if you screw up it doesn't get hurt...lol
 
Latest effort:

1. Switched to 60mm radius (I don’t yet have a 40mm).

2. Used bathroom scale to quantify my stroke pressure, I was using waaaaaay to light pressure. Increasing to 8lbs widened my strokes and produced more chips.

3. Using a bit of downward pressure when rubbing. I was applying effectively zero downward pressure and now rubbing 4 times left right and 4 times up down. Prints seem more clear and less smudgy / streaky now.

4. Starting my body stroke with my arms tighter into my body.

5. Trying to eliminate “dragging” the scraper blade on the back stroke and instead starting and ending my stroke hovering close to the work.

My aim needs…practice But despite that, I feel like the results are much improved!

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I have "Richard King Scraping Rules" I have my students memorize . If you can remember them and follow them as you practice you will improve. Your scraping.
1) Scrape Individual scraping marks - meaning separate each scrape mark with an opening as wide as that scrape mark
2) Scrape Individual scraping lines - meaning the next line of scraping marks do not touch the last line - separate minimum of 1/8" up to 1/4"
3) Depth of scrape mark - You have to measure the scrape mark with a Tenths indicator. Set indicator in a scrape mark and move the indicator to the next high spot. Minimum of .0002" to .001" deep. Average depth .0004 to .0005"
4) Hinge the part - meaning pivot the part on a surface plate or when rubbing straight edge on a way, hinge will be at 30% from each end.
5) Clean - Meaning rub your hand on the bluing and the part with you hand to "feel" the dirt before you rub

This teaches you how to scrape a checkerboard pattern. Also position your body so the scraper handle is at 45 degree's to the part - scrape one way and the next move your body so you scrape the opposite side at 45 degrees.

You need to always press down the 8 pounds and don't lighten up when you get more points. Having a small radius blade will help as long as you press down the same and follow the rules.
 
Awesome. Thank you so much for sharing this Richard!

I am planning to take your class sometime soon. I was hoping for the Salt Lake class but I think I need to wait for my son’s high school baseball spring season to be over first.

I saw your post about classes in 2022 being limited. I am hopeful that something will pop up on your schedule in the summer or fall.
 
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