Thanks Thanks:  0
Likes Likes:  0
Needs Pictures Needs Pictures:  0
Picture(s) thanks Picture(s) thanks:  0
Page 1 of 2 12 LastLast
Results 1 to 15 of 16

Thread: Scraper Mk1

  1. #1
    Join Date
    Oct 2007
    Location
    Sydney
    Posts
    3,112

    Default Scraper Mk1

    G'day guys, with a lot of interest on scraping at the moment I thought I'd put up some pictures of a scraper I quickly knocked up. It was just made up from material I had around as I was very keen to try the carbide. This was just something to hold the carbide and actually perfect the honing setup rather than a serious attempt at a permanent scraper. However I thought I'd try something other than flatbar just to see how it would go, and maybe it would allow me to get easier access under certain situations. I have some 25 mm flat bar and will make a copy of a commercial scraper and compare.


    The holder is designed to securely hold radiused blades, and while it may not look like it, it actually holds them extremely securely. Originally it was intended to be used "wrong way up", so the force was against the handle shaft rather than the brass holder. However in practice that wasn't necessary, and the taper underneath allows a flatter angle if needed. Unfortunately I didn't have any M5 countersunk socket heads, so this puppy was used instead. I'll replace and modify once I restock.


    The assembled scraper, a definite departure from commercial scrapers but that's fine by me. A good experiment, even if it's to discover that it's not the way to go!



    Longer shot of the complete scraper. I'd finished for the night so the plate was about to be cleaned but still has the blue on it. Indeed I can still see where the plane I was scraping sat on the plate when I spotted it so I'll throw up a few images of that for a giggle just to prove that it works

    Pete

  2. #2
    Join Date
    Sep 2002
    Location
    Minbun, FNQ, Australia
    Age
    66
    Posts
    2,012

    Default

    Nice job, hope it works as good as it looks.
    Cliff.
    ...if all you have is a hammer, everything looks like a nail...

  3. #3
    Join Date
    Oct 2007
    Location
    Sydney
    Posts
    3,112

    Default Carbide

    These are the carbide blanks I'm using. Obtained from Enco in the US for about A$3.60 each. I lashed out and bought 3!


    The raw blank is behind as I receive them, in front is one I was using, radius is approximately 80 mm and about 200 mm. I was just freehanding on the diamond wheel, and while they are quite symmetrical I didn't think the actual radius was especially critical so didn't measure it. The centre still has some rough surface however it's nowhere near the edge so doesn't affect anything.


    This was a bugger of a shot to take, so sorry but it was the best I could do. The surfaces are very shiny and it's quite close so focus is an issue. Anyway, the edge I was using was at the top and it can hopefully be seen that the bottom facet needs a touch more honing.


    The hone is an aluminium plate and the rest a piece of wood cut at 5 degrees on the compound saw. I made up another rest in steel, but it was an experiment. I know it all looks very ... errr "agricultural", but it actually works extremely well. The wood is the correct height so the carbide is horizontal, angled down at 5 degrees, but with the wheel running ALONG the blade and not across it. This was a highly critical discovery, as I initially had it an normal centre height angled up as one would expect a normal rest, however I found that was causing micro fractures along the edge. Extremely small, but enough to show as scratches on the work

    Edit: I took off my buff to use this end of this grinder, hence the mess. The diamond paste doesn't come off the plate at all, the green around the shot is from the buff.

  4. #4
    Join Date
    Oct 2007
    Location
    Sydney
    Posts
    3,112

    Default

    Hi Cliff, yes it works

    I decided to give my poor old Record hand plane yet another hammering. I swear the sole of that thing must be just about translucent, it's had so may "experiments" conducted on it! It was actually scraped a couple of years ago, however I was using my HSS scraper then, so time to drag out poor old Buster for another walloping

    I was messing about while trying to get the hone working correctly not really paying much interest to what and where I was scraping. To start afresh I decided to throw it on the surface grinder, at least then I hoped it would be roughly flat.


    It looks "ok" from here, however ...


    ... the surface plate thinks otherwise. Even though I was very careful with the heat and let everything cool right off before just touching with the wheel, just a few degrees is enough to warp the plane longitudinally. Not only that but I was holding in a vice and clamped down much harder than I needed to. The results in the edges are obvious where the vice was holding.


    Off we go! I had no idea just now much I needed to take off at this stage and was pussy-footing around far too much. I should have laid out thicker blue to give a better idea just how much needed to come off. I was happy my grinding was otherwise flat however, quite smeared on thin blue.


    Getting there. About now I stopped scraping the toe to tip the plane back and thereby save a lot of scraping. Obviously precise fore/aft alignment isn't necessary in something like a wood plane.

    ... to be continued.

  5. #5
    Join Date
    Oct 2007
    Location
    Sydney
    Posts
    3,112

    Default

    ... cont.


    This shot shows the obvious shift in scraping to tip the plane backward. No idea if this is a "correct" procedure, but it did exactly what I intended and I think saved a lot of scraping down.


    The plane is finally in one plane, and from here I simply started to spot finer. Unfortunately the blue starts to get a bit thin and hard to photograph, but basically the smurf-freckles just get smaller and more of them. They were quite even. I could have kept going but it was never the intention to have this as a project, just an experiment to make sure the hone etc worked as it should. After a bit of a dreadful false start I found the carbide was a much sharper edge than my HSS scraper, and although it's German, it may also have something to do with the type of steel they use. I doubt it's especially good quality. The carbide held its edge nicely and was quite sharp.


    This is where I stopped. Sorry but I find it real tricky to photograph a scraped surface, the light makes the surface look uneven, but that's not the case at all. Indeed it looks like there are great big divots at different places! They spotted evenly so I guess that's just a trick of the light. Again sorry, but the best I could do.

    For the "woodies" here. I took the blade out and spotted the sole without it, it definitely changed the base. Indeed I had to re-tension the frog and blade pretty much precisely the same as when scraped in order to get the flat pattern back again.

    Anyway, maybe that's of interest to somebody. If nothing else my 2 year old likes the pretty pattern

    Pete

  6. #6
    Join Date
    Jun 2008
    Location
    Victoria, Australia
    Age
    74
    Posts
    5,080

    Default

    Hi Pete,

    Was that made from a turning chisel? Nice idea..

    I'm planning on copying the Sandvik style..

    Regards
    Ray

  7. #7
    Join Date
    Oct 2007
    Location
    Sydney
    Posts
    3,112

    Default

    Ray, just the handle came from a turning chisel. I picked it up when I was at McJings IIRC years ago and knew it would come in handy some day. The shaft is just some plain old 12 mm square section I turned one end in the 4 jaw to take the handle, the other was milled as shown.

    Yes Mk2 will be a replica Sandvik and I picked up some 25 x 5 mm flat bar while I was getting some argon today. This scraper works just fine, so I may hold off on Mk2 until I have an actual scraping job pending instead of making Buster's sole even more translucent.

    Pete

  8. #8
    Join Date
    Jun 2008
    Location
    Victoria, Australia
    Age
    74
    Posts
    5,080

    Default

    Hi Pete,

    The handle was what I was looking at, because, I'm trying to understand why the scrapers I've seen pictures of all show fairly rounded "ball" shaped looking handles.

    I imagine it's so you can push with the palm of your hand more easily, although I think I recall a post by .RC where he said he was using his shoulder to push the chisel for more force.

    Dunno, just trying to understand the way it's supposed to work...

    Regards
    Ray

  9. #9
    Join Date
    Oct 2007
    Location
    Sydney
    Posts
    3,112

    Default

    Mate don't ask me, I'm just bumbling along.

    I didn't need to use much force however, the carbide cuts beautifully by itself. HOWEVER I should have got stuck into it a lot more in the early part. Maybe RC, GregQ, or one of the other pros can let us know on that. My other scraper has a pretty standard looking handle on it too, but I don't think it's a serious scraper by these standards.

    Pete

  10. #10
    Join Date
    Nov 2008
    Location
    Perth WA
    Age
    71
    Posts
    6,458

    Default

    A few things Pete.

    What's caused the streaks in the surface ground finish? And, do you reckon 25 x 5 is going to be stiff enough? I don't know if Sandvik use anything special steel wise. What did you buy, 1020?

    BT

  11. #11
    Join Date
    Aug 2008
    Location
    near Rockhampton
    Posts
    6,216

    Default

    The Morgan book says before that initial spotting to do a two way scrape over the entire surface to break it up which allows the spotting to happen... as you can see in the first picture, the blue has smeared and not spotted...

    It also says when you see where the pattern is to start doing double cuts to cut down on scraping time.. Going back to single cuts when you start getting a pattern over the entire surface..
    Gold, the colour of choice for the discerning person.

  12. #12
    Join Date
    Oct 2007
    Location
    Sydney
    Posts
    3,112

    Default

    Quote Originally Posted by Anorak Bob View Post
    A few things Pete.

    What's caused the streaks in the surface ground finish? And, do you reckon 25 x 5 is going to be stiff enough? I don't know if Sandvik use anything special steel wise. What did you buy, 1020?

    BT
    Hey Bob, I think again that's just a bit of a light thing causing the obvious streaks in the photo. In the end I was just touching the wheel and it's probably just a micro variation in the wheel diameter across it that is causing these tiny variations. Stuart or Ray may possibly be able to explain it. The amount is stupidly small, by that I mean spotting medium (of any description) looks like a mountain compared to the depth of these streaks. When I did this I just dressed and used the wheel that was in the machine, I have no idea what was in there, if I remember, out of curiosity I'll have a look later. The intention was only to get a surface that was relatively flat so I didn't need to scrape as much, I wasn't really concerned with how it looked. Having said that, I definitely could have dressed the wheel better. I realised that as I started grinding, but to redress the wheel would have meant removing the plane and it was a bit of a process to get it held accurately level in both directions just as it was.

    As for the steel, isn't the Sandvik 25 x 5? I bought some different sizes while I was there (offcuts are 25% less, so I always buy bar ends and offcuts while I'm there to go in the "this will be useful one day" rack), one was a 4.5m "offcut", thank you! However too much wider and I think it would be getting awkward to hold??? The steel is still in the tray, so when I bring it in I'll see. Maybe a tiny bit of flex in a scraper is a good thing? I can imagine that could help control it better. I'd expect it will be 1020, but no idea. I always mark my steel even if it still has the ends still painted and I'll be marking all these as 1020, but whether flat bar is actually 1020 or something similar I'm not sure. Again, maybe other members may know precisely what grade of steel is used in products like flat bar, RHS etc.

    Thanks Richard, both those points make sense. As mentioned, this was just intended as a crash test dummy rather than a "project" per se. However I did learn a lot going through the whole process that I will take away and hopefully remember when I'm doing this for real. The main thing for me is to not screw around at the beginning, if metal needs to be removed, then remove it and don't play with it. I really didn't want to go low, and with the carbide cutting so freely I was nervous that I would cut too deep, but after a while it was pretty obvious that wasn't going to happen. In that regard, again in hindsight, I could have played with the hi-spot thickness on the plate and I would have seen precisely how much needed to come off. Double cutting would have been a good idea.

    With regard scraping the ground surface. It's a bit strange to scrape, the blade wants to skid on the surface, then it begins to cut once it gets below that ground "skin". However if the blue is smearing wouldn't that still indicate that the surface in that area is very close to being at the same level, at least in relation to the thickness of the blue?

    Pete

  13. #13
    Join Date
    Nov 2008
    Location
    Perth WA
    Age
    71
    Posts
    6,458

    Default

    Yes Pete, the Sandvik is 25 x 5.

  14. #14
    Join Date
    Jun 2008
    Location
    Victoria, Australia
    Age
    74
    Posts
    5,080

    Default

    Hi Pete,

    The streaks are probably uneven wear on the the wheel, did you do a sparkout pass?, the last passes on the grinder are usually a couple of slow passes back and forward with zero downfeed, until you see no sparks, called a sparkout pass.

    Stuart might be able to offer some other hints..

    Regards
    Ray

  15. #15
    Join Date
    Oct 2007
    Location
    Sydney
    Posts
    3,112

    Default

    Quote Originally Posted by RayG View Post
    The streaks are probably uneven wear on the the wheel, did you do a sparkout pass?, the last passes on the grinder are usually a couple of slow passes back and forward with zero downfeed, until you see no sparks, called a sparkout pass.
    Yep did that. I forgot to look at the wheel on the machine

Page 1 of 2 12 LastLast

Tags for this Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •