# First scraping attempt: a Denis Foster 8” Featherweight straightedge



## jeremysf (Mar 10, 2022)

Hello all!

I thought I would share the experience of scraping my first straightedge. I am just getting going on it in earnest so I’ll share progress posts here as I go. 

Over the past few months. I have been watching many YouTube videos, purchased and watched Richard King’s scraping videos, reading books like Machine Tool Reconditioning and collecting hand scraping supplies.

I bought a few different straightedge castings and decided to start with Denis Foster’s 8” Featherweight casting. I am glad I did because it’s both a beautiful casting and also because Denis is awesome and has been a great source of advice and recommendations about machining the casting.

Here is what the casting supplied by Denis looked like:







Denis offers them machined, but I opted for a raw casting to maximize the learning. Despite being unmachined, Denis does a nice job cleaning up the gate and any flashing and egregious uneven high spots.

After explaining the machines in my shop to Denis (a PM-1054 mill with a 6” Kurt vise), Denis suggested I could mount the vise parallel to the bed, remove the vise jaw plates, and clamp up the casting with some thin pieces of plywood for both friction and to take up some of the irregularity of the sides of the casting.






I started by machining the back of the casting using a cheap 3” shell mill with carbide inserts that I had lying around.

After machining the back, I rotated the casting and indicated it in with light taps using the back as a reference to machine the sole of the straightedge.






After checking squareness on the surface plate, and finding it was pretty darn square, rather than indicate and tap in the top, I just clamped it in the Kurt using the back and sole as a reference against the fixed jaw and throat of the vise. I used the thin plywood to take up the irregularity of the unmachined thin edge of the 45 degree face and cut the top flat.






In that same setup, I side milled the ends for aesthetics. 

Finally, I used a small high quality rafter square to set up the 45 degree face  Yes, that is far from a precision setup, but in discussion with Denis he suggested the 45 degree is not intended to be a precision angle, to not give myself fits trying to make that perfect and it greatly simplified an already fussy setup. I did use an indicator to double check squareness to the sole and back faces.






Checking my work on the surface plate with my steel Starrett master square, and despite my nascent machining skills, the cuts all came out surprisingly parallel and square! Even the 45 degree angle ended up as dead nuts as I could measure with my Mitutoyo precision bevel protractor. Score one for the rafter square!






Next up: my first attempt at scraping!


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## jeremysf (Mar 10, 2022)

Before getting going on any scraping, I hinged the part on the surface plate. It hinges on corners and/or the extreme edges which is about what I expected as any subtle out of tram on the mill and the 3” shell mill shows up as ever so slight dishing on the work.

Better than being high in the middle to start!

View attachment trim.A5885BC8-BB1F-4BEF-B224-F9E17D33B1FE.MOV


For scraping, I’m using a Dapra hand scraper. I bought it along with a selection of carbide blades from dapra.com. Not cheap, but super nice stuff.

I was worried the Dapra scraper would be too stiff, but with the extension on it, it has a bit of flex to it which is cool.

I set up a little clamping jig out of 2x4s and machinist jacks to hold the straightedge securely on my welding table. I might switch to a form fitting wood “vee” jig rather than this clamping jig. The clamping holds the straightedge super securely, and with the wood involved, I doubt the clamping is introducing much stress into the straightedge, but hey, what do I know! The main reason to switch jigs is the time it takes to clamp and unclamp during the scraping cycle using the machinist jacks.






Before scraping. I drew out a set of cross hatch guide lines, took a deep breath, and dove in!

I managed not to dig the corners of the scraper into the work, and did a few practice / roughing passes, alternating 90 degrees after each pass. Not great, but not terrible!











I am trying hard to use my body to
work the scraper rather than my arms. I have more control with my arms, but as I found out using them to scrape near the edges of the work, using one’s arms to scrape gets old fast!

The initial few roughing passes didn’t change the hinging, which was expected. I then concentrated my scraping on the hinge points at the ends, leaving the rest of the sole alone and…success!

I managed to move the hinge points closer to the ideal 1/3rd marks. I am not even going to bother bluing until I get the hinge points closer to the ideal 1/3rd marks.

View attachment trim.3C016794-1A7F-4A63-870D-1665C60D13C2.MOV


I didn’t expect to have so much trouble gaging which part of the scraper blade was in contact with the work. In other words, I’m not yet consistent with the left/right spacing of a stroke relative to the previous stroke.

I am also much better at controlling the end of my stroke near edges than controlling the location of the start of my stroke near edges.

My stroke length is also all over the map.

After a few rounds of concentrating on the hinge points to move them closer to center, here’s what the sole is looking like:






A long way to go get on this project and so much room for improvement, but very pleased with my first evening’s attempt at scraping!


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## Aukai (Mar 10, 2022)

I know nothing about scraping, but your giving it a good go


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## graham-xrf (Mar 10, 2022)

Yay! This is pretty good.
In between adventures with electronics (in the cause of machine hobby), I also have started out on some little scraping adventures.
To get an idea of where to scrape when roughing, you can use an indicator on a stand, even a magnetic one stuck on a bit of a metal base, and get an idea of the pre-scrape parallelism by approximate mapping with a sharpie. It's a bit of a downer to scrape one side flat, and discover it forces a re-cut on the other side because it started out as a bit of a wedge. That would not be likely with your machine, and the big Kurt.

Even for roughing, a few quick tests with some spotting does help. I discovered some artist's oil paint in ochre rouge (rusty colour) shows up nice, wipes away, and does not leave you looking like a smurf, (borrowing Stefan's phrase). The piece I had was allegedly already cut, but I found the fastest initial flattening was with a file, and I even resorted to a Dremel-type grinder to lower the high spots at the ends.

I can't start a cut at the edges without digging in. I make any cuts at the edges start somewhere on the material, and cut to go off the edge, keeping the same general strokes direction matching the rest. Either I turn the piece around, or I go to the other side.

BTW - you do great pictures! We like that here.


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## ConValSam (Mar 10, 2022)

Very interesting project. Good on you for diving right in!

And a 2nd on the excellent quality of your images.


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## jeremysf (Mar 10, 2022)

Making progress! I’m now hinging at thirds and am printing high spots using canode blue on the surface plate:

View attachment trim.BC1DCCAD-4BE9-4F27-A380-26187F721116.MOV


I started using a base contrast layer of canode yellow after deburring and before hinging and printing on the surface plate. Definitely making things easier to see, but a little nervous my inexperienced application may interfere with the printing. Continuing on using the yellow for now.




I’m finding the canode paint very “sticky”. I wasn’t expecting that. A little bit of worry that I’m adequately removing dust from the surface plate and the part; it’s hard to tell using my hand to wipe the plate with the thin layer of sticky blue on it. The part also sticks more when rubbing than I expected. I’m trying to rub by only touching the ends of the part and gently moving just an inch back and forth to avoid smudges and/or false prints.

My biggest issue right now is my total inability to re-sharpen the carbide. It’s definitely dulling after a few passes and swapping to a fresh edge is *magical* for the feel and result of the scraping.

I have tried using a 1200 grit diamond stone and also semi free-handing on my deckel clone with a 400 grit diamond cup wheel. With the deckel I can set the rake angle but am free-handing the radius, following the existing radius.

The result though is just not sharp. I have always been **** at sharpening / stoning cutting edges. I guess now is the time to learn, but it’s an extra variable I don’t love having to figure out at the same time as scraping.

Here’s a fresh “factory” edge:




and then a failed attempt of mine:




Will need a bit more research and practice, so may pause the scraping for a bit until I can figure out how to effectively sharpen and hone the carbide blades.


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## Richard King 2 (Mar 11, 2022)

jeremysf said:


> Making progress! I’m now hinging at thirds and am printing high spots using canode blue on the surface plate:
> 
> View attachment 399796
> 
> ...



Is this HSS? It must be as Carbide would not do that?  The other picture is Carbide blade.  I would just use that.  As far as a Carbide Lapper goes.  https://www.hobby-machinist.com/threads/glendo-lapper-clone.11032/   just Google Glendo Lapper alternative.


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## Richard King 2 (Mar 11, 2022)

Dennis makes some nice straight edges as many of us do.  I like his straight-edges but he and I have some issues...lol  Gary Martin up in Portland makes some nice ones too.  He sells his for less then I can have my cast.  He is a pattern Maker and works at a foundry.  That's why I bet...lol  I have been telling folks lately to check out his.








						Camelback Straight Edge
					

Camelback Straight Edge. 52" size is a special order item. Please inquire at martinmodel@comcast.net



					www.martinmodel.com


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## jeremysf (Mar 14, 2022)

Richard King 2 said:


> Is this HSS? It must be as Carbide would not do that? The other picture is Carbide blade. I would just use that. As far as a Carbide Lapper goes. https://www.hobby-machinist.com/threads/glendo-lapper-clone.11032/ just Google Glendo Lapper alternative.



The photo is actually carbide as mis-shaped freehand by me on my Deckel grinder clone with diamond cup wheels.

I have paused on scraping while building two things:

1. An attachment for the Deckel to allow me to use it to grind carbide blanks with the 5 degree bevels and a series of radius’ without having to freehand.

2. A slow speed lap that uses 6” steel discs coated with diamond dust. I’m using a 1/4hp motor and pulley and, taking inspiration from Stefan, am holding the discs using magnets and a pin.


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## jeremysf (Mar 15, 2022)

Here’s some pictures of the custom little table / jig I made for my Deckel clone to grind and dress carbide scraping blades.

I’m using 400 grit diamond cup wheels for shaping the radius initially, and a 1000 grit diamond cup wheel for dressing / touching up blades once they get dull during scraping.

The jig supports 120mm, 90mm and 60mm radius scraper blades by moving the pivot screw between the three positions.

To use it, I infeed with the precision knob on top and sweep the arm on the jig, rather than sweeping the entire knuckle like one would when grinding a single lip cutter.

Now with a reliable way to grind and touch up my scraper blades, I’m back in business on scraping my first straightedge.


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## Richard King 2 (Mar 16, 2022)

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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## jeremysf (Mar 16, 2022)

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.



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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## Richard King 2 (Mar 16, 2022)

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


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## Richard King 2 (Mar 16, 2022)

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


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## jeremysf (Mar 16, 2022)

Thank you Richard!


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## jeremysf (Mar 17, 2022)

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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## Richard King 2 (Mar 17, 2022)

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.


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## jeremysf (Mar 17, 2022)

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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## jeremysf (Mar 18, 2022)

For those playing along at home, I decided (in conference with my son) to skip a few baseball games and attend Richard’s Salt Lake City class


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## francist (Mar 18, 2022)

Well, based on that, I’d say your son has the makings of becoming a real stand-up guy. Actually looks like he is already..


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## jeremysf (Mar 19, 2022)

He’s a good dude. Handy around the shop on the lathe, mill, TIG welder and angle grinder. He wants to be a mechanical engineer, so making sure he has a foundation in actually doing rather than just designing


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## Aukai (Mar 19, 2022)

Must look more like the mom.


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## jeremysf (Mar 23, 2022)

Made a few more passes on the sole and the 45 degree face and in addition to getting a bit better through practice, two big improvements for me are:

1. I put a 600 grit diamond wheel on the Deckel clone and am now correctly grinding down into the carbide blade. I knew better, but in my excitement over trying out my jig, I had angled it 5 degrees the wrong way. The results are WOW. Super sharp carbide and a MUCH easier time scraping.

2. I added a better pad to my Biax/Dapra hand scraper and I wouldn’t have thought it would make such a difference, but it’s soooo much easier to body scrape now.


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## Richard King 2 (Mar 23, 2022)

Another tip is to drill and tap 1/4" 20  holes into the ends so you can hold it better.  Put in a hex bolt with a jam nut on it.  Then tighten the bolts between to vises or 2 Johanson wood clamps.  It will hold better and not wiggle in the wood V block.


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## arsenix (Jan 4, 2023)

Did you ever finish scraping? I'm also thinking about picking one of these up as a first scraping project!


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## ltlvt (Jan 4, 2023)

I have the exact same casting and have also completed the milling on mine.  Same results on the first hinging.  I have not yet started the scraping process yet due to not having any good scraping tools or a way to re sharpen them. Good tools are always on my bucket list. Thanks for bringing us along.


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## pontiac428 (Jan 4, 2023)

Just saw your scraper sharpening setup on page one.  Great minds think alike?  Matched the factory radius, added 1 degree of toe.


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## arsenix (Jan 5, 2023)

I also concerned about sharpening my scraper blades. I do not have a dedicated sharpener sadly.


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