1. Welcome to TalkBass, the Premier Bass Player Community and Information Source. We've been uniting the Low End Since 1998!

    We're glad you've found us. Register a 100% Free Account to post and unlock tons of features.

Manton Customs Tutorial On Chisel, Plane and Spoke-shave Iron Sharpening

Discussion in 'Luthier's Corner' started by Manton Customs, Feb 25, 2014.


  1. Manton Customs

    Manton Customs UK Luthier Supporting Member

    Joined:
    Jan 31, 2014
    Location:
    Shropshire, UK
    Disclosures:
    Luthier, Manton Customs
    Hello all,

    I just thought I would share this tutorial on sharpening which I have put together. I had a full set of chisels to sharpen and thought I would make it a bit more interesting by taking pictures as I go. I'm sure some of the newer people to instrument building will find it useful a long with anyone who perhaps hasn't fully utilised these wonderfully versatile tools in their work. I'm sharpening chisels in the pictures, but the process is pretty much the same for plane and spoke-shave irons.

    Chisels
    As we are working on chisels here I'll go into a bit of detail on them. The set you will see below is a vintage set made by Marples, Sheffield dating to probably around 100 years ago. I would advise anyone who is seriously interested in instrument building to buy vintage rather than new, there was a quality to the steel back then which doesn't seem to be matched these days. I'm sure if you were going to spend a lot of money you could get something of similar quality, but the cheaper brands just don't compare. Another great thing about vintage ones is that they are cheap to purchase and once you have done they will last you your life. Some makers of chisels to look out for are Sorby, Marples and Ward. Marples are in fact still going, but the quality is not the same.

    Ok, lets begin! Here are the very few tools you will need: An Oil Stone, a Honing Guide and some Cutting Oil....plus whatever you will be sharpening!

    [​IMG]

    Firstly you will need to make sure your Oil Stone is flat, if it is not as this one pictured here isn't, you will need to lap it flat. This can be done over a coarse grit paper attached to a flat surface, the stone is then pushed over this till dead flat (keep checking with a straight edge).

    [​IMG]

    Lets now take a look at the state of the chisels we are going to be working on, or more specifically the bevel. The bevel is the sloped cutting edge, this can vary from 25 degrees to up to 45. Shallower angles are better for shaving while more steep ones for chopping type jobs. In guitar building the latter is rare, so we are going for a 25 degree bevel. The chisels currently have around a 30 degree bevel, so there is going to be quite a bit more work here than simply honing the cutting edge...we need to create a new bevel (or rather re-shape it). As you can see the blade is in good condition with no chips to the edge, if chips were present we would need to re grind it completely on a bench grinder. Another great thing about chisels...they're pretty much indestructible as you can always grind a new cutting edge!

    [​IMG]

    Now lets look at the honing guide, this is the device that holds the chisel at a fixed angle. You will see the different angles mentioned on the guide with a measurment next to it. This is how far the blade needs to project in front of the guide, for a 25 degree bevel we need 25 mm of blade in front of the guide (as pictured).

    [​IMG]

    Here is the guide in action, the oil stone has been wet with cutting oil and the guide with chisel attached is pushed and pulled backwards and forwards. At first in both direction (back and forth) until we get close to the finish, when it is only pulled along the stone.

    [​IMG]

    You need to be careful to distribute pressure across the guide or you will end up like the picture below (see how the right edge is higher than the left?), this is no big deal, it just means you need to put more pressure on the other corner until it evens out. Don't think you can just put even pressure on it and get it right...you cant! You need to keep checking your progress and putting pressure on different points. You should be able to see what we are aiming for now, we want that silver line close to the edge to come all the way down to the cutting edge.

    [​IMG]

    Here you can see we are nearly there, you can just see a tiny silver line on the right edge. This shiny part has yet to be touched by the stone, all the previous grinding has just been grinding the bevel. So we keep going until it has vanished!

    [​IMG]

    And here we have reached the cutting edge, this is how it should look before progressing onto the finer side of the stone. After a few strokes over the fine side you should be noticing a burr on the back edge (flat side) of the chisel, you want this to be quite pronounced before moving on. Feel for the burr with your thumb nail, you will notice it catch and take a tiny part of your nail with it!

    [​IMG]

    Now we have to remove the burr we have just created, this is done by rubbing the back side along the stone like the picture below. Once you no longer feel a burr on this side, check the other side, it will almost certainly be there having bent over from the flat side, so a couple more passes on this side over the fine stone. Repeat this till there is no burr on either side.

    [​IMG]

    How do you know when you are done and your chisel is sharp?...When it does this! All that hair you see is from my arm, a sharp chisel should be able to shave the hairs off your arm easily. If it does not, repeat the last couple of steps (creating the burr and removing the burr) until it does.

    [​IMG]

    The final step is a process called stropping, this gives the blade a bit of polish and sharpens even further. Its basically rubbing it up and down a piece of smooth leather as you may have seen people do with straight razors on TV.

    [​IMG]

    And here are the chisels with their new bevel all done and ready for the next job.

    [​IMG]

    Thank you for reading this, I hope its clear enough and it helps someone. :)
     
  2. pilotjones

    pilotjones Supporting Member

    Joined:
    Nov 8, 2001
    Location:
    US-NY-NYC
    Thanks! I may have to buy one of those guides. I've been eyeballing angles, but the guide is probably a better idea.

    What grit of stone are you using, and what do you think of other types of stones - water, Arkansas, etc.?
     
  3. Manton Customs

    Manton Customs UK Luthier Supporting Member

    Joined:
    Jan 31, 2014
    Location:
    Shropshire, UK
    Disclosures:
    Luthier, Manton Customs
    Thanks for posting on this, I thought it had gone un-appreciated, I hope it has been useful to others too!

    Yes, a guide is a very good idea, you'll find your work becomes much easier having the bevel accurately ground as it makes a big difference!

    I'm not sure if it's different in the US, but over here generally oil stones aren't sold in with grit numbers, but with fine/medium/coarse grades. Water stones are sold in grits (which I have used before), but I personally prefer the oil stones as they last much longer before lapping. I just use the medium and fine oil stones before progressing to the strop, if it needs a lot of grinding to begin with I will use a bench grinder to get it close, though try not to be impatient so only use if necessary. I would say that not to sweat the fine polishing too much if you are intending to use your chisels...if its sharp enough to shave with, then you're good to go. Polishing to a mirror isn't necessary, though giving the strop a couple of passes every now and then while using can prolong the edge.

    Hope this is of some help.
     
  4. pilotjones

    pilotjones Supporting Member

    Joined:
    Nov 8, 2001
    Location:
    US-NY-NYC
  5. Register to disable this ad
  6. JustForSport

    JustForSport

    Joined:
    Nov 17, 2011
    Thanks for sharing all this info with us- the whole process.
    I didn't know what type of guide to get, and it seems that some have a single wheel in the center, which may make it harder to keep/ dress a straight edge (altho there's some pros to a slightly curved edge).
    May try to get a Stanley like the one shown, tho- not sure if the newer ones (cast) are good enough?
     
  7. pnchad

    pnchad

    Joined:
    Nov 3, 2005
    I need to learn to edge all my tools
     
  8. lbridenstine

    lbridenstine

    Joined:
    Jun 25, 2012
    Location:
    MI
    I appreciate you posting this too! I need to sharpen my spokeshave and plane blades soon. Probably my chisel too (I only have one).
     
  9. Manton Customs

    Manton Customs UK Luthier Supporting Member

    Joined:
    Jan 31, 2014
    Location:
    Shropshire, UK
    Disclosures:
    Luthier, Manton Customs
    Great, glad it has proved useful :). Exactly the same procedure for those (a 25 degree angle works well for these too) and both are lovely to use when sharp, though painful to use when dull!

    You're welcome. Yes, there a lot of variations and most will work well for you though the Stanley one is actually surprisingly good because it has a handy angle ruler attached. It has the measurements on the guide as pictured but also a little fold out measuring stick with the angles marked on, so it saves having to measure with a ruler. Sounds like a little thing, but its really useful!

    Yep, a curved edge can be useful on certain types of chisel (and even plane) to prevent the corners of the blade digging in. But for a majority of the time I like a flat edge on standard irons/chisels.
     
  10. flameworker

    flameworker Supporting Member

    Joined:
    Jun 15, 2014
    Location:
    Landenberg, Pennsylvania
    Disclosures:
    one day....
    Thanks for this, I didn't know about a honing guide, Pretty sure I have one knocking around somwhere, can't wait to have all nice chisels again!
     

Share This Page