This is how I make steel doming punches to shape soft metals (gold, silver, copper, brass,) for jewellery making.Doming ( or dapping punches as they are often referred to by jewellery makers) punches are expensive for what they are- basically highly polished pieces of curved steel. I have a few comercially made punches and a brass dapping block but I needed larger ones for a project. I couldnt justify the expense knowing they would only see occasional use, so I made my own.they are cheap, easy and quick to make with only a few tools, yet they still delivers excellent results.
The tools are straight forward,1) Sanding sticks of various grits Ive used 120, 240, 320, 400, 600, 800,1200.2) A few loose pieces of sand paper of various grits3) Buffing stick (an old leather belt glued to a piece of hard wood) or a polishing motor with stitched cotton buff.4) Buffing compound (Ive used blade honing compound as it cuts steel quickly, you could use jewellers Tripoli or brasso with good results)5)hack saw.6) A file.
For this project Ive used an old carriage bolt (domed bolt). As I dont have a lathe to remove large amounts of material a piece of preshaped steel was important to reduce the need for labourious hand work ( this project is about saving money not losing time)DONT CONFUSE STEEL BOLTS WITH LEAD HEADED ROOFING NAILS!!!lead is super soft and will conform to the shape of whatever it is hit against, meaning flat lead not domed metal.when considering the steel you need to take into account the curve of the face. This bolt head is approx 28mm wide and 7mm deep. which is appropriate for the curve i want, you may need to look for a few different sizes before you get what you need. If you are going to use your finished tool in a commercially made dapping block CHECK that the dome will fit! also some carriage bolt arent 100% round, if the arent made round they can mar the side of the dapping block.For a small punch a large nail or small bolt could be ground or filed to shape as less material needs to be removed.It is also necessary to consider the condition of the face, you want it to be as smooth as possible, again to reduce the amount of work required to produce a quality tool.Give the bolt a quick rub with 400 grit paper to help show any bumps or dings- As you can see in the photos there are several marks in this bolt, there is the raise type along the top and a dent just to the left of the centre.
It is important that the tool is comfortable to use. This particular tool was to long.Mark and cut with a hack saw.The length of the shanks of the commercial doming punches I own vary between 8 an 12cm Ive cut this one to be just over 9cm long.
Gently round the end of the stump. this is an important step. by rounding the end, even by only a few degrees you create a small crown this helps to direct the force from the hammer blow straight down the punch even if the hammer does not strike the punch perfectly flat.
In the initial stages of shaping you want remove the bumps and dents identified in step 2, and if necessary modify the shape to suit your e a medium cut file to remove bumps and dents from dome, you want to use long sweeping strokes of the file. Starting from close to or on the outside edge, angling towards the centre you want to cover as much of the face with each smooth stroke as possible.IT is important NOT TO FILE FLAT SPOTS ON THE DOME! this will result in an uneven finished product.
In this step we continue to shape the punch with sand paper and remove the tool marks from the previous step.Depending on how coarse the file or grinding stone was in the previous step, start with either 80 or 120 grit paper.With the sanding stick use the same long strokes that you used with the file. The idea is to remove all the tool marks left by the stone or spect the dome once you have sanded its entire surface. Then take a loose piece of the same grit paper holding the piece of paper in the palm of your hand rotate the dome against the paper. This help to even any out the sanding marks and leaves the dome with a uniform surface for the next grade of paper.For a scratch free finish it is essential to remove all marks from the previous paper before starting on the next grit. So using the 240grit paper make sure you cant see any deeper scratches left by the 120 paper before progressing on to 320 or 400- It will be impossible to remove these later with having to start the sanding again.Repeat this step, working your way through the different grits of paper coarsest to finest right up to 1200.
Once the dome was been sanded up to 1200 grit it should have a uniform face. To achieve a mirror finish it is necessary to polish the dome. This can be done either using a polishing motor or if you dont have access to a polishing motor with the use of a buffing stick.To polish with a buffing stick load the leather with compound by rubbing the stick over the polishing compound. Then vigorously rub the stick back and forth over the surface of the dome. This is can be quite a labour intensive excercise and while a true mirrior finish is hard to achieve good results should still be possible.NB: DANGER in the photos posted I dont have a guard on the motor. Not only is this bad practice it is extremely dangerous- polishing motor run at SEVERAL THOUSAND R.P.M. if what you are polishing goes flying there is a high probabilty you could be seriously hurt.To polish using a polishing motor load the wheel by lightly touch the polishing compound to the spinning wheel. Hold the dome between 4 and 5 oclock on the wheel ( the position not the time) dont dig the dome into the wheel but rather use a firm even pressure youll get a feel for the correct pressure quickly. Move the dome so the face receives an even polishing (with softer metals it is possible to polish a groove into the surface- we dont wont this) Inspect your progress often.Then rotate the dome 45 around its centre and start again- this is to polish out all the little scratches let by the 1200 grit paper as polishing perpendicular to a scratch is more effective at removing it. repeat this rotation and polishing several times until the dome has been polish from all angles.THINGS TO REMEMBER WHEN USING A POLISHING MOTOR:NEVER OPERATE A POLISHING MOTOR OR GRINDER WITHOUT A GUARD ON ITALWAYS WEAR SAFETY GOOGLEShold the item you are polishing firmly to prevent it from being pull from your handTake your time youll get better results.watch out that the piece doesnt get to hot, you can actually burn yourself.
If you have a commercially made dapping block that your dome fits in you can use it. however if you dont have one you can also use a block of lead, urethane or a sand bag.(If you using a lead block with silver or gold make sure that no lead is transfer to the metal by using a thin layer of latex or plastic wrap. Failure to do this can result in pitting of the silver or gold when heated.)1) Cut a small circlular metal disk,2) Place the disk on lead or dapping block of appropiate size3) Centre the punch on top of it4) deliver a few blows with an appropriate sized hammer5) inspect your results and enjoy the wonderful feeling that comes when you make something yourselfENJOY D.P
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Thank you for this, each step of the process has been so well illustrated and clearly explained that even I can follow it!
Personally I have used this method to create domed washers for a project I put the drill in the vise and the domed bolt into the chuck and switched on the drill and sanded it that way.
I might put my bolt in a drill or drill-press (or lathe as suggested) and sand it while spinning, to prevent uneven shaping.
pm sent i like these tool of your makeing makeing my own is what i like if need a morw solid dapping block kor thin ss any ideas?
Do you think I could use this by putting it in my vice, and put a piece of sheet metal on top, and hit the metal with a hammer to shape it however I please?
Definitely! thats a great idea. In jewellery making working sheet metal into a 3D form in the way you describe is called raising. there is no reason why a doming punch couldnt be used for that.
Actually its called Repousse raising is using a hammer to move the metal upward while working on a blacksmiths anvil stake.
You are correct in saying the punch can be used for repousse and even as a small stake to do some really small scale raising.
We were taught in MCTCs Jewelry program to do this with a soft hammer. The vice chews up the handle of the punch, so be warned : )
I wrap leather around my punch or whatever before putting it int the vice
this is cool you think i could use this and keep hitting a penny and reshape it or is it way to thick (the full copper one not the new one
you can shape a copper penny this way. i recommend you anneal it first. To anneal copper heat it to an even cherry red colour then quench it by plunging it in cold water. As the penny bends it will work harden so you may need to anneal it again during forming.
You seem to have described tempering as opposed to annealing. If you wanna get a good, soft annealed medium youd want to heat it up and very, very slowly let it cool, as in 10 degrees Fahrenheit per hour. For bigger stock when blacksmithing sometimes youll put it in a campfire and get it nice and hot, then let the smoldering embers and ash completely surround it then let the fire die down. If you let it burn down over night, and its buried in ash, then by the next day itll still be warm and have cooled down VERY gradually. The more gradual, the softer the annealed material will be.
I bet you even putting it in the oven at a high temperature for like an hour and 15 minutes then every once in a while lowering the oven temp. a little would anneal it pretty nice.
What you described is akin to tempering it at a low heat (dull cherry red), so while it wasnt that hot to begin with, itll be tempered and therefore soft but still much harder than ideal. Tempering locks in the structure formed at high heat and embeds a hardness in the metal. Annealing relaxes all the stressed metal structures that form, and make it nice and soft and workable.
I only hope that this helps you make even cooler stuff in the future, and do it more easily and better.
For steel, you are correct. But for copper, heating or torching and then dunking it in water will make it soft, especially if you have very thin (24gauge or thinner) copperitll bend like paper. You can also try it out on a pre-1982 pennyyou wont be able to fold it but it will bend very easily with pliers. Post 1982 are only copper plated and melt FAST in a flameyes, thats personal experience talking! lol
For people who dont have a polishing motor Im sure if you look at this lathe Instructable youll be able to find inspiration to improvise something.
You can get buffs that have an arbor for a drill, as well. Put the punch in a vice and move the drill around.
This is a great idea! Thanks for breaking down the steps so well. I have a set of dapping punches, but I do not have larger sizes. Im sure Ill need to make one or two of these sometime. Also, thanks for the tip regarding placing plastic wrap between your metal and lead block. I have been using paper and cant see what Im doing! I never even thought of using plastic. Good times.
You can buy a whole set of these at Harbor Freight for cheap on sale now and again, save a lot of time and effort. But I do like the idea.
You rock man! We shop at HF all the time and I never thought to look there. I have been pricing this set for a year now thinking there was no way I could afford it. thanks!
I bought a set a year or two ago, I think it was like $20 or $25 on sale, it has the other side mandrels too, for punching with the doming punch. If you sign up for HF emails, they send out 20% off coupons every couple of weeks, that makes it even a better deal, and sometimes the catalog will have those too.
The mini lathe (link posted below) is also a fantastic way to shape and sand the doming punch -provided it fits in the chuck.