What's inside
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What Final Honing Actually Does
After you have ground a primary bevel at 25 degrees and honed a secondary bevel at 30 degrees on stones to 4000 or 8000 grit, you still have a wire edge. Under a loupe at 10x it looks like a thin, ragged foil hanging off the tip. Final honing is not about removing a lot of steel. It is about stripping that burr cleanly and polishing the last 0.2mm of the bevel so the two planes meet in a true zero-radius intersection. Done right, it drops cutting resistance noticeably. In pine or poplar, a properly honed 3/4-inch bench chisel will pare end grain with two fingers of pressure instead of needing a mallet tap.
The choice between plain leather stropping and diamond paste comes down to how aggressively you want to abrade that final intersection, how much tolerance you have for rounding the apex, and how often you are willing to refresh the surface.
Leather Stropping: How It Works
A traditional strop is a piece of smooth, vegetable-tanned leather glued to a flat hardwood or MDF substrate. Used bare, leather does almost no cutting. It is slightly compressible and charged with the stray grit left from your stones. It burnishes and folds the burr back and forth until it breaks off. It is forgiving, but slow.
Most woodworkers load the leather with a honing compound – the classic green chromium oxide bar. That compound is about 0.5 micron, roughly equivalent to 30,000 grit. A pea-sized amount rubbed into the leather gives you a very fine abrasive that cuts just enough to polish. Stropping technique is simple: bevel flat on the leather, pull edge-trailing only, 10 to 15 light strokes per side with the weight of the chisel only. No pressure. Lift, flip, repeat. If you push edge-leading you will dig in and slice the leather.
The failure mode with leather is rounding. Because leather compresses even when glued to a board, it wraps slightly around the apex. If you use heavy pressure or do 50+ strokes chasing a mirror polish, you will dub the edge. You will still get a shiny bevel, but the chisel will skate on hardwood instead of biting. On a hanging leather strop, like a barber strop, this effect is even worse. For chisels and plane irons, always use leather bonded to a flat, hard backing. A good leather strop for chisels on a flat board costs very little and will last years if you keep it clean and dry.
Plain leather or green compound is fast enough if you hone often. If you come off an 8000-grit waterstone, you need only 6 to 10 strokes to remove the burr. Where leather struggles is when you jump from a coarser stone. Coming off a 1000-grit stone, green compound will take a minute or more of stropping and you still may not fully erase the deeper scratches.
Diamond Paste: How It Works
Diamond paste is monocrystalline or polycrystalline diamond suspended in an oil or water-soluble carrier. It comes in syringes graded by micron size: 3 micron, 1 micron, 0.5 micron and 0.25 micron are common for woodworking. For reference, 1 micron is about 14,000 grit and 0.5 micron is about 30,000 grit, but diamond cuts far more aggressively than chromium oxide at the same particle size.
You do not apply diamond paste to soft leather. You apply it to a hard, flat substrate – MDF, hard maple, balsa, or a cast acrylic plate. A grain-of-rice sized dot spread thin is enough for the whole surface. On MDF or maple, diamond does not compress. It stays at the surface and cuts the steel directly instead of burnishing it. Three to five light, edge-trailing strokes on 1 micron paste after an 8000-grit stone will produce a visibly brighter, more uniform polish than 15 strokes on green compound, and it will remove micro-burrs that leather alone just folds over.
The trade-off is aggression. Diamond paste will remove steel, and it will do it quickly. That is an advantage if you want to skip a fine stone. Many carpenters working on site hone to 1000 grit, then jump straight to 1 micron diamond paste on MDF to refine the edge without carrying a full progression of waterstones. The disadvantage is that diamond leaves a more scratchy polish at the same micron rating and can create a slightly toothier edge if you stay at 3 or 1 micron and do not follow with 0.5 micron. It also embeds in the substrate. Once you charge a board with 1 micron, that board is a 1 micron board. Do not mix grits on the same face.
Diamond paste also needs occasional refreshing. The carrier dries out in 6 to 12 months and the surface loads with steel swarf. A wipe with isopropyl alcohol and a fresh application restores the cut. Cost per syringe is low, but you will use it up eventually, while a green compound bar lasts almost indefinitely.
Head-To-Head Comparison
If you are deciding what to keep in your tool roll, this is how they stack up in practice on O1, A2 and PM-V11 chisel steels:
| Aspect | Leather + Green Compound (0.5 Micron) | Diamond Paste on MDF/Hardwood (1 to 0.5 Micron) |
|---|---|---|
| Cutting Speed | Slow, burnishing action. Needs 10-20 strokes to clean burr from 8000 grit. | Fast, true abrasion. Needs 3-8 strokes to clean same burr. Can refine directly from 1000-4000 grit. |
| Edge Sharpness | Very keen, polished apex. Typically shaves arm hair and pares softwood cleanly. | Equal or slightly keener at 0.5 micron. More consistent burr removal on wear-resistant steels like A2 and PM-V11. |
| Risk of Rounding | Higher if you press hard or strop more than ~20 strokes. Leather compression wraps the apex. | Very low on hard MDF or maple. Minimal dubbing even with moderate pressure. |
| Best Grit Jump | Works best after 6000-8000 grit. Not efficient after 1000 grit. | Works after any grit. 1 micron after 1000 grit is a common site shortcut. |
| Maintenance | Scrape, re-apply compound every few months. Keep flat and dry. | Wipe with alcohol, re-charge with small dot. Do not cross-contaminate grits. |
| Cost Over 2 Years | About $15-25 for a board and compound bar. Lowest cost. | About $12-20 per syringe. Need 1-2 syringes. MDF is free scrap. |
Which Should You Buy for Site and Shop Work
For most bench work where you already own 4000 and 8000 grit stones and you hone at the bench, plain leather on a flat board with green compound is completely adequate. It is cheaper, quieter, and you do not have to manage multiple pastes. If your chisels are mostly O1 steel, leather will get them as sharp as they can usefully be for dovetails, hinge mortises and general paring. There is no practical gain in paying for diamond for this use case.
Diamond paste makes sense in two situations. First, if you work with A2 or PM-V11 irons, which hold a burr more tenaciously. Chromium oxide can skate over those carbides instead of cutting them. One micron diamond cuts them cleanly and you will feel the difference in fewer strokes to get a burr-free edge. Second, if you want a minimal kit for site work. A double-sided MDF paddle with 3 micron on one side and 1 micron on the other plus a single 1000-grit diamond plate lets you go from grinding to finished edge without waterstones. That saves weight and mess in a tool belt and site kit where you need to touch up an edge on a joist or window jamb.
Many experienced joiners keep both: a hard MDF board with 1 micron diamond for the first step of final honing, and a leather board with 0.5 micron green compound for a final 5-stroke polish. That two-step sequence gives the speed of diamond with the smooth polish of chromium oxide, and it limits time on the compressible leather so rounding is not an issue. If you only want one, choose diamond on MDF. It is more versatile, and the risk of ruining an edge by rounding is lower.
Technique Matters More Than Product
Both systems fail the same way: too much pressure and too many strokes at a raised angle. Keep the bevel flat on the strop. Lock your wrists and pull straight back, not in an arc. Use no more than the weight of the chisel – about 200 to 400 grams of force. Count strokes. If the edge is not sharp after 10 strokes on diamond or 15 on leather, go back to your finest stone. You have a burr that stropping is not fixing, you are just polishing the burr itself.
Check your work by feel and by cut, not just by shine. A truly honed chisel will not catch a fingernail when you drag it lightly across the edge, and it will pare end grain on soft maple without crushing the fibers. If you see a bright line at the tip under a good light, that is a reflected flat where the edge is rounded or still burred. One or two light, alternating strokes at exact bevel angle should erase it. If you keep stropping and the line persists, you have rounded the apex and need to re-establish it on stone.
Keep strops clean. Steel swarf embedded in leather or MDF will scratch the bevel and actually dull the apex. Cover them or store face-to-face when not in use, and never use the same strop for both paste grits.