Power scraping. Anyone tried to convert a Makita HK0500 for metal? - Page 2
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  1. #21
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    Quote Originally Posted by Forrest Addy View Post
    Good grief -- $40/lb!

    I just found it on Ebay for $34 per Kg:

    http://cgi.ebay.com/ws/eBayISAPI.dll...m=300138592144

    Anyone want to split a kilogram with me?

  2. #22
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    Quote Originally Posted by Forrest Addy View Post
    Here's some more from my old writings:
    Thanks for the lead write-up Forrest!

    Some interesting comments from the red lead page at the artist supply store. The first one indicates how much oil to mix with the lead:

    Properties

    Oil Absorption: 6 g linseed oil/100 g pigment

    Toxicity
    Red lead is highly toxic, and utmost care should be used in handling the dry powder pigment to avoid inhaling the dust or ingesting the pigment in any form.

    Is red lead really that toxic? I thought the health issues were related to long-term exposure through ingestion?

    This is the lead toxicity entry in Wikipedia. Isn't 50 microgram per cubic meter a lot?
    Workplace Air

    The OSHA Lead Standard specifies the permissible exposure limit (PEL) of lead in the workplace, the frequency and extent of medical monitoring, and other responsibilities of the employer. OSHA has set a PEL (enforceable) of lead in workplace air at 50 µg/m3 averaged over an 8-hour workday for workers in general industry. NIOSH at CDC has set a Recommended Exposure Limit (REL) of 50 µg/m3 to be maintained so that worker blood lead remains < 60 µg/dL of whole blood.[40] The ACGIH has set a threshold limit value for a time-weighted average (TLV/TWA) of 50 µg/m3 for lead in workplace air (except for lead arsenate).[41]

  3. #23
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    Great. So which one of you goop spreading guys is figuring out how I can get, buy, or make a power scraper?

    I don't quite follow the difference between the analogy of the sawzall vs. the power scraper (Makita). I looked at both parts drawings and they use the same cam mechanism for the reciprocating motion, but one is smoother than the other?
    Of all the tools the chinese have copied and spread like manuer all over this country, why doesn't HF sell a chiax power scraper? -Mike

  4. #24
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    Quote Originally Posted by Holescreek View Post
    Great. So which one of you goop spreading guys is figuring out how I can get, buy, or make a power scraper?
    Sorry Mike!

    Of all the tools the chinese have copied and spread like manuer all over this country, why doesn't HF sell a chiax power scraper?
    'Cause there's maybe 100 guys left on Earth who still scrape, and 80 of them are here

  5. #25
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    Ive trained 102 (official count from the original rosters) scraper hands so there's more than 100. Maybe there will be more in the future.

    I'm working on some preliminary drawings of the power scraper conversion. I can post it soon to maybe inspire a few to making their own.

  6. #26
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    I had several tubes of GM pinion setting marking compound that was bright yellow with a consistancy of blueing (this was probably from the '70's). They made an excellent contrast with prussian blue, but the stuff came in incredibly small tubes, like maybe 1/10 oz. Anyone know what I was actually using, and if it is available in larger sizes?

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    I haven't yet mastered even a paint scraper, but it'd seem like air would be useful for a metal scraper. A double-acting air cylinder, variable valves, and some position readout to a controller should allow variable stroke & cycle rate in a small package.

    May as well add more stoopid to the idea:

    Why not recoilless unit with a reaction mass thrown opposite the scraper blade, to cancel out the vibration, reduce the need for a heavy tool to do that?

  8. #28
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    Quote Originally Posted by joecr View Post
    I haven't yet mastered even a paint scraper, but it'd seem like air would be useful for a metal scraper. A double-acting air cylinder, variable valves, and some position readout to a controller should allow variable stroke & cycle rate in a small package.
    There was an article in HSM magazine many moons ago (I think it might be on MetalwebNews too) about making a scraper from an air file. Guy said it worked great, but he had a really tiny scraping tip, so I don't know if he ws scraping little model engineering machines...

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    Ok - which is worse, red lead or chrome yellow?

    "Chrome Yellow is a natural yellow pigment made of lead(II) chromate (PbCrO4). It was first extracted from the mineral crocoite by the French chemist Louis Vauquelin in 1809. Because the pigment tends to oxidize and darken on exposure to air over time, and it contains lead, a toxic, heavy metal, it has been largely replaced by another pigment, Cadmium Yellow.

    It is commonly produced by mixing solutions of lead nitrate and potassium chromate and filtering off the lead chromate precipitate."

  10. #30
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    Quote Originally Posted by William E Williams View Post
    Ok - which is worse, red lead or yellow lead?

    "Chrome Yellow is a natural yellow pigment made of lead(II) chromate (PbCrO4). It was first extracted from the mineral crocoite by the French chemist Louis Vauquelin in 1809. Because the pigment tends to oxidize and darken on exposure to air over time, and it contains lead, a toxic, heavy metal, it has been largely replaced by another pigment, Cadmium Yellow.

    It is commonly produced by mixing solutions of lead nitrate and potassium chromate and filtering off the lead chromate precipitate."
    Looked up some of that stuff. Some called chromium yellow is mostly lead ("Chrome Yellow"), but some is pure Cr2O3 (Chromium Oxide Green LIght")
    http://www.pigments.com/inorganic.html#yellow

  11. #31
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    Biax has an air powered model. I guess all the Biaxes on Ebay must have dried up. Some time ago there were a number of them available. I got a scraper and a flaker. I only wanted the flaker,so I sold the scraper to a friend. I have a new biax scraper. The flaker was pretty worn out,and made a continuous wavy line rather than separate half moons. But,the mechanism is very simple,so I made a new part for it and hardened it. Works pretty well now. As for the other brand of scraper being sold,mentioned above,that was being offered in the tools and accessories section of this forum. may still be there.
    Edited: No,the scraper isn't there anymore. as for converting an air file,stroke would not be adjustable,I guess,and you really need the weight of the Biax to resist the cutting stroke,and the variable speed.
    Last edited by gwilson; 07-07-2008 at 11:58 AM.

  12. #32
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    OK, you forced me into it. I try not to use my imagination too much but I think I figured out a quick cheap and easy way to make one of these things. So far I have $19.99 into it and a couple of hours machining. It will have both variable speed and adjustable stroke length from 0 to 1.25". In a little under 2 more hours of machining I should have a working prototype that anyone can make and afford. -Mike

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    Hi Mike...

    Are you going to post your idea here for the rest of us Biax wannahaves?

    Greg

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    OK here it is. First let me say that I am self taught in scraping and have ever used a power scraper. I stopped by the local import tool store and picked up a $20 sawzall. I opened up the transmission as soon as I got it home.

    Cleaned up:

    Based on the previous comments I would need variable speed and stroke adjustment. The tool already has variable speed. All I had to do was make the stroke adjustable.

    Stroke is adjusted by loosening the set screws. Unfortunately the design requires removing the rubber boot, 4 screws remove the top and then the set screws are in view.

  15. #35
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    I had a small scraper blade I found in my grandfathers tool box that was about 5/8" wide and 5" long. I trimmed the steel down to fit into the blade clamp.

    I tried a couple of cuts on one of my current projects. I'm sure practice will improve the look somewhat, but I really just needed a rougher to get this bed down close enough to finish by hand.

    This one'll get the thread locked:

    -Mike

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    Wink

    Quote Originally Posted by Holescreek View Post
    This one'll get the thread locked:

    -Mike
    Well, I hope Milacron or others cut you some slack when you are creating a "proof of concept". Seems to me I may have one of those guys floating around somewhere.

    Ha. The wife wonders about my hand scraping. Little does she know....Off to do battle with a chunk of versa-bar, Chink tool in my scabbard....Dulcinea, we are coming...(humming theme to Don Quixote.)

    Doug

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    Default Get thee to your local machine shop

    Find a mill and ask them how much. With the money you save buy a biax. Are you "hand scraping" with a file? Cause that carbide tip ain't sharp at all.

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    Quote Originally Posted by gentle View Post
    Find a mill and ask them how much. With the money you save buy a biax. Are you "hand scraping" with a file? Cause that carbide tip ain't sharp at all.
    gentle,

    I'm not sure if your comment was addressed to me or not. (No disrespect intended if you are talking about something else. I was referring to a chunk of 1"x2"x10" versa-bar that Forrest Addy provided in his class, not something I'm going to carry into a CNC machine shop. If I told them I wanted to make some 1-2-3 blocks out of it, could you please machine this to half a thou or so, to to complement my $7 ENCO purchase, well, ya get the picture.

    The Biax is a nice machine. It also costs $2500. Not gonna happen for me.

    Remarkably, I didn't think the scrapers Forrest provided seemed sharp either. I wouldn't want to shave with it. I don't think you could cut your finger with it if you tried. Carbide tipped, diamond honed to a mirror finish. And they scraped. Half a thou here, half a thou there....Beautiful!!

    Doug

  19. #39
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    Are you "hand scraping" with a file? Cause that carbide tip ain't sharp at all.
    No doubt there are a few bugs I need to work out including blade length, tool sharpness, stroke length, pressure angle... But those things are to be expected when concept to working model takes place in just a few hours. Where were your clever ideas when the question was first thrown out? -Mike

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    Default Re: Contrast media

    Forrest,

    After the scraping class in Vermont (April 2007) I got together the supplies I needed from several sources. All your recommended sources worked out well. From Dapra I purchased the Connolly book, a spotting gage, and some yellow media that came in a squeeze bottle. The yellow media appears to be water based. I haven't tried it yet. As I recall it was not that expensive. Here it is (top of page) on the Dapra website.

    -DU-


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