Hand Scraper Design

I'm monkeying around with making a scraper to repair the cross-slide on the 1440 and would appreciate some input from those that use them.
I'm attempting to do this with materials that I have on-hand. The lathe crapped out at very a inconvenient time.
I had to take a pass on a decent bit of side work because with the stick-slip, I messed up the first three pieces. So the budget is hurting.

Richard sent me a copy of Keith Rucker's design. (Thanks Richard!)
I have a couple of questions about the design.
I've got a few pieces of 3/4" Sqr. carbide inserts that I'm trying to make do with. I realize that they are really not wide enough, however it's all I've come up with.

On Keith's design on the insert extension piece, the flat on the end is at 2° positive.
Does anyone know why? I'm wondering if it can be 'straight'.
1544029137363.png..........1544029129748.png

Here's my first take on it using the 3/4" insert.
I'm making a couple of needed ergonomic / handling modifications to it.
I made up a mock-up out of a file and then played around with it trying to mimic the way I've seen people handle them in videos.
A problem/difficulty has cropped up from this, with my left hand tendons messed up from some medicine, gripping the scraper becomes uncomfortable after a bit.

With this first take, I've made a change on the handle end so that I can try out different size handles if needed. They will be screw on.

My Left-Handed/Right-Handed -ness is odd. I write left handed but do a number of other things right handed, it just depends.
I haven't figured out which way I'll hold a scraper yet.

If I'm holding the end with my left hand, 1.5"-2" DIA. feels best and lessens the discomfort.
Scaper_drh_002.jpg
Then I've also added a 'Grip' handle for holding the shank left handed.
Scaper_drh_001.jpg

Thanks,
_Dan
 
One of the cool things Tom Lipton was working on when we had the scraping class was a bump scraper, to make possible short and consistent length cuts with the thought of making precision scraping cuts exactly where needed. He brought one to demonstrate that was kinda' like a slide hammer, and in the discussion we talked about making bump scrapers with electric solenoid or air power. I don't know where that eventually went, but it is interesting. We did meet up with one of the class participants, Adam, at a Sturgeon's Mill tour, and he said he scraped in a tiny cast iron surface plate (about 2x2 inches) to 100 points per square inch with a homemade bump scraper -- just to see if he could do it. He was with his wife and a new baby, so we did not have time to talk about the scraper or techniques he used for that job. Richard showed us a way of bump scraping using the palm of the hand near the wrist to bump the end of the scraper handle, with the fingers supporting the scraper under the handle. I found it clumsy, or maybe it was just me not trying hard enough or long enough. Interesting stuff...
Now that sounds interesting.
Anything to take a little bit out of the physical efforts of scraping.
That one video of a class out by you where, I think is was NWAirgun, was asking you guys 'how are ya feeling', a couple of days into the class...

Is the bump scraping like what is in some of the videos where they're using a deadblow down near the end?
 
That one video of a class out by you where, I think is was NWAirgun, was asking you guys 'how are ya feeling', a couple of days into the class...
That was the second day of the class. By the end, we kept going all day with no problem.
Is the bump scraping like what is in some of the videos where they're using a deadblow down near the end?
I have not seen a dead blow hammer in use on a scraper. I suppose it would work OK if you had three hands...
 
That was the second day of the class. By the end, we kept going all day with no problem.

I have not seen a dead blow hammer in use on a scraper. I suppose it would work OK if you had three hands...
@19:11 on this one of Adam's at the class last year at Keith's.


and @7:19 on PartII of Vacaville right after some gent going at it with a Biax...


I was wondering if a deadblow 'slug' would be easier that a handled one.
 
@19:11 on this one of Adam's at the class last year at Keith's.


and @7:19 on PartII of Vacaville right after some gent going at it with a Biax...


I was wondering if a deadblow 'slug' would be easier that a handled one.
That is called "oil flaking" and it is not scraping. The idea of it is to make pockets that break up the surface to hold oil. Ground surfaces or worn surfaces, face to face, squeeze out the oil and then it is metal to metal and it galls. Flaking can be done by hand or by machine. It really is best when it is applied to the upper surface, facing down, than on the bottom surface, where the flaking collects grit and crud to wear the surfaces. But that is not what you typically see on machines, where they want it to "look nice" (or hide sins.) They put it on the bottom where you can see it. I did some oil flaking at the Vacaville class, both by hand and with a power flaking machine. It is not too difficult to do, but it needs the correct technique. If you don't do it all the time it takes some practice on scrap material to get back in the groove. Flaking on ways of machines like Bridgeports is often called "scraping", but it is not. Flaking cuts deep, and if it is worn through in places it means you are looking at a lot of wear.
 
Ive never did any type of hand scraping ANYTHING but i have a thought that might lend itself to helping the process along!
Has anyone setup a hand scraper in the form of a "Slide Hammer" type tool? Im not sure if it would be more of a help or more of a hindrance however I think that maybe adding a lightweight slide hammer onto the scraper shaft it might help make things move along a bit easier, What do you guys/gals who have this type of work experience think about that idea, possibly helpful or no?
 
Ive never did any type of hand scraping ANYTHING but i have a thought that might lend itself to helping the process along!
Has anyone setup a hand scraper in the form of a "Slide Hammer" type tool? Im not sure if it would be more of a help or more of a hindrance however I think that maybe adding a lightweight slide hammer onto the scraper shaft it might help make things move along a bit easier, What do you guys/gals who have this type of work experience think about that idea, possibly helpful or no?
See post #10 in this thread. Yes, that has been thought of. I think a DC electric solenoid pushing a rod of the correct mass and speed, and a trigger and a current controller, would work really well. but I haven't gone any further than that.
 
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Just for kicks I'll throw in my version. Being the frugal type(cheap), I used a piece of hot rolled from the local Home Deathspot and brazed the carbide on. For me, I found that I kind of cradle the scraper similar to a football. This also forces me to use my body instead of moving my arms. Meaning, I have the pad/handle pressing on my bicep and use my left hand to hold the scraper with my hand on top closer to the point of contact. This prompted a simple pine disc cut and a scrap piece of foam glued to it for some extra cushioning. In case you're wondering that is a variable speed treadmill motor used to sharpen my carbide. Did I mention I was "frugal"?:p Here's a pic of mine:
Scraping Stuff (4).jpg
 
See post #10 in this thread. Yes, that has been thought of. I think a DC electric solenoid pulling a rod of the correct mass and speed and a trigger. would work really well. but I haven't gone any further than that.

Wow I Better start reading the complete thread before I post something up!
Thanks
 
For me, I found that I kind of cradle the scraper similar to a football. This also forces me to use my body instead of moving my arms.

I thought I was the only weirdo that holds a manual scraper that way! I put a nice thick piece of foam on the end of my manual scraper. When I tuck my right elbow tightly into my side, the foam cradles nicely against my right bicep. Left hand up top at the front to control, hips and full body to power the stroke. That's my preferred stance for scraping horizontal surfaces. (Completely different, but it reminds me strongly of the body mechanics when hand-planing lumber: weight transfer from back to front foot, the "feel" and consistency of the stroke, and the definitive need to use larger muscles efficiently.)

I'm in the middle of a restoration where a hand scraper is actually a little more convenient than my ancient (and HEAVY) Biax for much of the work. For things like inverted ways where it's impractical to get the surface you're scraping horizontal, I take the the pad off of my manual scraper and hold the grip with my hand, but still tucked in against my body. I still use my body to power the stroke, but it's easier to control the odd angles with my hand on the grip.

If I lose focus and start using my hands and arms to power the stroke instead of my body, the marks become inconsistent real quick (and I get tired a whole lot faster).

I suspect the "football tuck" depends on the length of your forearm and scraper, but I found holding the end of the scraper against my hip or torso was harder to control. I want the length of the scraper and the direction of the push as parallel to my forearm as possible. Anything else just feels wrong to me somehow.
 
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