Updated: Jun 19, 2021
The polished face hammer is a very popular tool in leathercraft, but why do you need one, and what is the benefit over an unfinished hammer?
A regular hammer that you buy from a hardware store, or even a saddlers hammer, is left in a rather rough condition on it's strike face. This is because a rougher face will grip the head of a nail or tack much better than a polished one.
This roughness provides that 'bite' into the head of the nail, preventing it from slipping and striking the surface of your work.
But in our craft, we rarely use a hammer for striking nails into wood, brick, or even leather for that matter, so we don't really need a rough finish to grip anything.
While there are countless uses for a polished hammer in leathercraft, the main four that has me reaching for one is:
Flattening stitches after completing a seam for aesthetic purposes, and to prevent proud stitches from wearing out through friction.
Compressing two pieces of leather, or other materials after gluing to provide better contact and a stronger bond.
Compressing a turned edge after gluing to confirm the fold and provide a better bond with the glue used.
Doming a rivet or small nail whilst imparting a mirror polish transferred from the hammers face (hardened hammers only! 50+hrc).
In the above image, you can see a magnified screenshot from the video course: 'How To Make A Bag Frame' (release date June 8th 2021).
This stainless steel rivet was domed by using a polished hammer alone. For this purpose, I recommend a properly hardened construction hammer rather than a saddlers hammer which is usually too soft.
A ball peen hammer is ideal as it's designed for striking metal. The strike face is not damaged or marred after this process and should not loose it's mirror polish either.
However, rough hammer that hasn't had it's strike face correctly polished is likely to mark your leather or rivet, which leaves an undesirable finish to your work.
So, there we have our reasons for wanting a nicely polished hammer. A full mirror polish is not absolutely necessary for striking leather, but I find that extra step helps create sparkling rivets and it's also great for checking your lipstick 💋😘.
Step 1: Removing corners and facets.
A huge tip here: Use a marker pen to cover the area you want to begin smoothing out.
As you remove metal from all the sharp edges, you will clearly see where you have been working and where you haven't.
I have used pink and blue here just to provide a better visual image, so black or whatever colour you have is absolutely fine.
The hammer I am using here is a locksmiths hammer. It is square faced, similar to an engineers hammer, but my choice is based more on what spare hammer I had in my drawer to use as an example for you.
I don't necessarily recommend it over any other hammer, but I do recommend something in the 250g - 350g range (8oz - 12oz).
A square faced hammer is in fact the most challenging to polish due to all the sharp corners, so if I can do this by hand, you can do it with a much easier round face!
Hold your hammer steady in a vice, or use a clamp to hold it firmly to the side of the table. You can place it down on your thigh in a seated position, but it will be more challenging and messy (not to mention the hand ache!).
Begin removing the corner with a file where the strike face (coloured in pink) meets the first facet (coloured in blue).
Go around the hammer face in this way until it begins to disappear. Remove metal with the forward push stroke rather than scrubbing back and forth with your file.
If your file gets clogged with particles, use a wire brush to periodically clean the file of debris.
At this point I like to switch from a medium file to a very fine 'needle file', which means you can clean up any heavy scratches from the first filing.
I also round the edge slightly where the blue facet transitions onto the side of the hammer.
The goal is to have a smooth transition from the flat strike face onto the sides of your hammer.
In the pic above, you can still just about see see the scratches left behind from the factory grind on the strike face.
The marker pen in these scratches shows me that I have some more work to do with the file.
Stage 2: Smoothing.
In this stage, the main shaping of the face has been done. We aren't removing much material from here on in, we are simply trying to remove the scratches left by the previous stage.
For smoothing, I really recommend a sponge sander. As the name suggests, the core is made from firm sponge while the outside has an abrasive layer.
The sponge will mould itself around the steel to better remove any high spots and even out the face.
Starting with a medium grit, move the sander in a circular motion, then work your way around the outside of the face as well as the centre.
Keep going until you have removed all the scratches from the file. You can add your marker pen again if needed to highlight any deep scratches you may have missed.
When you are satisfied, finish with a sanding from a 'fine' sponge. You can buy multi-packs with various grades quite cheaply.
Above you will see 2mm EVA foam that I use for prototyping bags. Any craft foam is fine, or you can even use a doubled over piece of cloth or canvas.
This evens out the sanding and increases the surface area being worked on.
Now move onto a finer grit. For this, I recommend 1200 grit wet/dry sand paper.
The paper I am using is adhesive backed which sticks to the foam, but it's a luxury rather than a necessity.
Adding water prevents your sand paper from becoming clogged, so you can use one piece instead of several.
Begin by adding medium pressure onto your hammer, and move in a circular motion working your way around the face.
Make sure you work the sides as well as the flat strike face (and corners if you are using a square shaped hammer).
Next, move onto a finer grit like I am doing here with 2500 grit. If you aren't interested in using your hammer to dome and polish rivet heads, 2500 grit is fine to finish on if your hammer is only used for tapping stitches etc.
At 2500gr, you will begin to see your strike face becoming reflective. You can see my fingers waving at you (yoo-hoo!) on the left, but in the right light you can still see tiny scratches left behind from the abrasive particles. So next, we are going to remove this 'haze' in the polishing process.
Step 3: Final polishing.
Now you will need a leather strop with some polishing compound rubbed into it (I use Dialux Vert De Paris).
Most of you will already have this, but prior to using your strop, take a stiff bristle brush (nylon etc) and aggressively brush it down in all directions.
Quite often, strops pick up small particles from your work table and these can leave scratches as you polish which will be incredibly frustrating to you.
If this happens even after brushing, cut a piece of leather and apply fresh compound to the flesh side (after brushing it).
You don't really need to move in a circular motion anymore, back and forth (quickly) is fine. Make sure you polish all areas of the strike face as well as the sides until you can count the number of teeth you have when you smile 😁.
This will take a good few minutes, so relax your arms and shoulders, put on some Dave Brubeck and get polishing!
You hands may be achy tomorrow, but you will surely smile with a result like this! Especially knowing you did it all using basic hand tools you probably already had.
To eek out the finest polish that will rival the top Grand Seiko or Rolex watches, 'Cape Cod' polishing cloths will do the trick (I didn't in this example). But at this point, there isn't a real world benefit outside of checking who is the fairest of them all...(Snow White anyone?)
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