G'day everyone,
To start the year off right in the workshop, I thought it would be best to finish off a project that I started in December. And that is to make a punch for sheet metal. I am going to make it my aim to use more sheet metal in the workshop projects this year, but I need to sort out ways of cutting small features into it. For large stuff I use the angle grinder and files, and for holes I use a step drill. But for slots my go to was to use a file, which takes quite some time to do, especially if you have multiple to do.
But now that I have the press, I want to look into making a very simple punch and die that would have me make slots, and in the future more complex shapes if need me.
In this video I will first see if the fly/screw press is up to the job, and then I will look into constructing a more complex punch which I will then heat treat. I hope you enjoy the video.
Timestamps
0:00 - Intro
2:14 - Making The Test Punch
6:30 - Approximate Force Calculations
8:39 - Making The Slotting Punch
15:01 - Testing The Punch and Die
Hope you enjoy this one, it was a lot of fun making it. FYI if you are wondering why the press stand is bolted to the floor, it is not my workshop so can not drill into the floor. Cheers
You could still make it sturdier so half of your energy isn't wasted in the stand jumping all around.
Great job 👍🇬🇧
I haven't made many punches yet, but did run across an idea that might be useful, especially for larger punches... When shaping the face of a punch, mill it off at a slight angle, so that one corner/edge/end of the punch face enters the work first. The punch still moves at 90° relative to the work, but only a small part of the cut is happening at one time - more like a pair of scisors than a paper hole punch. Your tools and equipment- and more importantly your back! - will last a lot longer. ...LOL, I do have to admit that it probably won't help a whole lot with punching a 15mm long slot through 5mm thick aluminum! Should be awesome for 1mm steel stock though, and the edges of the cut will be cleaner too. Cheers.
dont cut stock by hand!
Sorry about the dozen odd copies of my comment. Had a slight browser malfunction here. (The rest should be deleted now. I hope!)
Rather than not minding, I honestly prefer the exploratory format. Thank you for sharing!
I completely agree. Seeing the experiment helps me understand how to make the tool (or something similar for my needs) much better.
Here are a few tips on piercing metal that may be useful. The punch and die need to have clearance between them. This is typically 10% of the material thickness PER SIDE although this varies depending on the result required,it is a good compromise. If you want the hole or slot to be a certain size then the punch is made to that size & the additional clearance is on the die. If you want the slug (blank) to be a certain size then the die is made to that size & the clearance removed from the punch. So in your case the punch should be the size of the slot required & the die 20% of the material thickness to be pierced, bigger overall. The relief in the face of the punch will not help with cutting pressure as it cuts on the perimeter only. Typically cutting force is reduced by a shear angle on the face of the punch, usually along the longest length. This angle is usually the material thickness over the punch end length ( slot length in your case ). Piercing metal on a press can often be performed with just a punch & a rubber die. Aside from the advantage of not having to make a die, alignment is not an issue. A rubber die can also perfom bending & forming around a punch. Here are a couple of examples on my channel to explain better. kzhead.info/sun/lc2wqsmhlqKqaJs/bejne.htmlsi=FKs0tjkWDjZRTG6k kzhead.info/sun/l7N6hseCaHV5oJE/bejne.htmlsi=8MUNXfyOzw5D-rCG I hope you find these tips useful.
I have 10 years of experience with sheet metal fab specifically in the punch press mass fabrication. This is it. I was going to type up my own dissertation but yours is correct. Cheers from Nevada.
As a tool and die maker i can agree to that comment. Cheers from Germany
wow thanks for the tips! what type of rubber is used? this looks excellent for forming, combined forming/punching and for when you want a small positive shape. however if you wanted a slot in a larger part is there any way to stop the part from warping like what happens in your video examples? seems like it kinda wastes alot of material. maybe the part/blank could be clamped from above to stop it warping?
To prevent warping, a couple things need to be insured. the die must be flat. A slight angle from the die face would be similar to a ball ping hammer going at it to the sheet metal surface. Too much tonnage can also cause warping especially with forming tools. And yes it’s a tad wasteful especially when punching out large cutouts but it’s metal. The waste slugs can be recycled. A savvy operator can get an extra part from big enough cutoffs. A well programmed punch turret can output insane quantities of parts so the wasted material is negligible when the cost of the parts are worth more than its weight. This machine has been my bread and butter for 10 years plus programming the thing. kzhead.info/sun/bJ2cdNRreYSwoqM/bejne.htmlsi=rbZz37o5grvjj_19
relief on the tool will help with extraction though.
It’s honestly refreshing to see a this type of content. Opposed to the type of KZheadr with a massive CNC, water jet cutter, top model mill and lathe, etc etc, All just “sitting in their garage” It all feels inaccessible and becomes boring. Your content feels like we’re on a journey with you. I look forward to more videos
For someone who looks at something like this just because they like it and has no idea at all about metal and how to process it, experiments like this are particularly important. These often help to understand the context of why or how something works.
Sheet metal really helps solve alot of problems. It's nice to see you also look at this side of Metalworking. :)
To help with the burr, try making the clearance on the dies 10% of the material thickness. That may also help the sticking if the burr is getting caught. Great video
Thankyou for the suggestion. Cheers
Interesting to see the production process of the part and your thinking behind it. Very educational mate. Good work!
This is vodoo, holes need to be drilled in my world.
I definitely don't mind these types of videos. Hell I love watching people make tools and come up with different solutions to problems. Congratulations making a tool that worked the first time! Most of mine need a version 2 or 3 etc. before I get a working example.
Nice! A former place I worked at actually had 5 old fot operated pendulum presses. They were used in production to about 2010 for small batches. Very quick to set up and very quick to lose fingers as well. We either used like a fork from the side or like a urethane rubber that fitt on the punch to pull the part of. The proper play will get the most of the burrs away. 1mm thick plate will need 0.15 to 0.2 mm play. 2mm 0.3 to 0.4mm. If you bore a pocket in a plate you can use smaller round dies that you lock in with a setscrew, much easier to grind sharp too. the die holder can have threaded holes for fixturing
Videos like these help me determine what approaches are worth pursuing in my own projects. Sheet metal has always looked attractive, but seeing how well die punching works, for how cheap it is, really makes it hard to ignore.
Maybe if you put a slight angle on the cutting tool. So it's not the entire surface cutting through it at once but rather punching through a very small shear edge. Maybe that'll help with lowering the pressure needed to force your way through your sheet metal.
same comment from me ;) In theory, it help, I think. But on small pieces maybe not that interesting, and the angle may depends on the thickness of the sheet
Generally the larger the tool is a greater need to apply an angle to the tool. Sheering or long cutting tools that are thin are shaped like an “upside down house.”
@@Pacheko36097 @archloy the downside to adding shear to punches is that it can cause side load which in the same way as nibbling and also it takes away from the amount of actual stroke the press can achieve. Also it increases the time taken to sharpen the tool It only will reduce the shear force by a percentage, and that percentage depends on how much the surface area is reduced. In practical terms its often only 10-15% reduction, but none the less effective
@@thierryboudanphotography4562I’d imagine a V profile would fix the side load issue?
I think now I understand where the name “spring pass” comes from!
I think you may have the wrong idea ? But there is humour in the reference you implied.
I always look forward to ur vids. Some of the best metalworking content👍🏻
a tip to reduce the exerted force: the cut face could be inclined, so you have a small portion of the force used as the tool advances
I certainly like experimental stuff like this. A lot to learn from how you approach things.
Mind? This was brilliant! Loved the format of "Here's the idea, let's make it happen and see if it works!"
As a former press tool designer, you have done pretty well with your experiment. However, the clearance between punch and die is pretty important. It can make a big difference to the force involved and the life of your tooling. Also the quality of the hole/slot. Maybe check that out fir different materials, if you are going to be doing it a lot. For small runs its less important. Cheers mate!
Absolutely love these experimental type videos. And it’s so nice to see your press meeting expectations. I’m also very interested to see what kind of constructions you make with sheet metal. I think that would be accessible to a lot more of us.
I enjoy this type of learning projects.
Great video, and always interesting to see what you can do with simple tools. Regarding the energy it takes to press through metal, have you looked into relief in the dies? The die must be bigger for thicker metal, othervise the pressure needed is greatly increasing. If you look at the cutting surface, it is split between a flat, smooth and part and a more rough, cut part. On a properly sized die, the thiknes of the smooth part should be 1/3 of the material thikness. Hope this helps
bottom also need's be hardended. And dont do "relive" on punch, it only get it worse to take part out. Also You can just add stell plate over die to hold part while punch is returning after cutting. PS. If you "hardedned" it in water and it didnt broke, then You dont get enough temperature to hardend it properlly. Cheers! PS 2. size of burr is depended of clearance between die and punch. In industrial its ~7% of thickness matterial who you are cutting, double for stainless. PS 3. in bad centricity you can do 135degree cutting edge. It would help up to ceter punch and die.
Love the learn as you go vids 😊 I'm a tier 1 automotive tool maker and enjoyed the lovely simplicity of it 😊
Very nice depiction of your trial and prove methods. An amazingly good outcome for your efforts as well. Enjoyed very much, cheers!
First off, awesome of you to navigate through the construction & application of a punch & die! With over a decade in the Tool & Die industry and co-owning a manufacturing business spanning three generations, I can attest to the vast complexity surrounding such a seemingly simple setup. Your creation closely resembles that of an Ironworker. Over the years, we've had competitors try to copy some of our machine tooling. Sadly, they encountered an instance where misalignment led to a lethal accident, including the punch exploding under high tonnage, shooting punch shrapnel through the operator's heart. Today, most Ironworker machines incorporate safety measures like impact-resistant polycarbonate to mitigate such hazards. I urge you to consider integrating similar safeguards, such as mounting a barrier between the punch and yourself, to ensure your safety while operating. You can find material for the barrier on McMaster pretty inexpensively.
Great show. So simple to make.
I can't believe I've watched all your weekly videos for months and was not subscribed. Love the channel.
No, I don't mind these type of videos, they're very interesting!
Nice video. Makes the point that you never really know what you can do unless you try. And that's when the learning part starts too. Nice punches and it shows how an idea can become reality... Thumbs Up!
I do mind hehe I think these experimental videos are even better, so keep them coming! Today I learned how to calculate the sheer force.
This was a good watch! Thanks!
Neat idea with the spring. The punching press in our shop has shoe that can be adjusted and fixed over the workpiece which prevents the die from pulling back up the material
Heck yeah, man! Experimental videos where you make a new tool and test it is very ideal. keen for more!
I definitely enjoyed this video. It gives confidence that if we try todo something similar, we should have success. Thanks.
Like such research into a new area. Cheers 👍💪✌
One thing you can do to lighten the load is make your punch at the desired dimensions, but angle the tip so instead of the punch engaging the entire surface all at once, the punch begins at a spot and the cut progresses around the shape. Like the punches electricians use to cut circles out of junction boxes, the cutting edge is a high-low wave around the punch.
Fantastic work! 👍
nice testing and iteresting. cheers ben.
Love this type of vid. Nice work!
if no toolsteal try spring leaf/rod heat temp & retemp 250/300f used it for ages in spring industry for small jobs leaf if treated right will cut spring steel tension springs easy
Excellent work!
I found another use for my surplus Moccona jars - fill with oil for quenching. Resealeable lid & see thru container was a bonus in case I dropped the part.
Very interesting indeed mate, thanks dude.
No I don't mind at all. Try wiping oil on the underside. It should make punching occur heaps easier, as far as pressure to break through goes. Putting the cutting edge of the punch on an angle will help with thicker material even more. I have a sloppy cheap hydraulic press so a die holder would be needed to make use of my own ideas about this here. To keep the male/female components aligned. So much of what I do is bespoke components that require a drill bit in the correct spot where a majority wont fit in the press at all. Also marking out has to often, be done after welding. Still I am very interested in this method since tools like butterfly wrenches and impact drivers have found their way into the site and plasma is in the shop now also. The most impressive item recently added is a cold cut chop saw. Always room for more if it can be used occasionally! Good video.
Two things that might help you. On your punch, looking at it from the side, picture a very shallow angle v shape. Maybe just 5 or 10 degrees on the legs. So the outer edges contact and cut thru before the center contacts the workpiece. Look at pics of Greenlee brand hole punches as an example. Really reduces needed tonnage. For the spring you might try and automotive valve spring or on from a small engine like a motorcycle. They are heavier and shorter than what you used here. Just a thought on the springs but I can tell you the v shaped punch face will help.
Cool project!
Don't apologise for these experimental videos. In some ways they are more interesting than your other videos. I'm looking to make a punch suitable for making shim washers in copper. They are available commercially but they are obscenely priced at around A$0.30 each and I need dozens. Your video has helped me develop my plans a great deal.
Great video, thank you 😊
Love it! THX! That helped a lot!
great little vid i too work with sheet steel, i'm a retired panel beater and a year or so ago i got a cheap plasma cutter, 55 amp plasmargon make, what a game changer that has been, i used to hate cutting big sheets up, i'd either use an air saw or grinder bother were accurate enough but hugley noisy and pretty slow going. the plasma cutter was stupid quick, like 10+ times quicker and very quite compared to the other two options, i work in my residential london garage so yeah p'ing off the neighbors i like to keep to a minimum as for the punching i wanted to swap out my garage gate hinges to have coach bolts instead of the scews so i needed to punch quare holes, sure i could have filed them but meh, too much time as i also wanted to use on other stuff i went with the vevor ch-70 hydraulic hole punch and its actually very good, punches through 10mm steel place with no problems at all, and you can get several shape punches including slot ones or you can make your own as for the sheet steel punching one of the first projects when i got the plasma cutter was to convert a workshop tool trolly into a plasma cutting trolly with a spark catcher so i could use it inside the garage rather than cutting stuff out side every time for risk of fires from wayward sparks, and the mess on the floor. the ch-70 made fast progress of the 40 or so 13mm holes i need for the sheet steel, drilling that many would have taken ages and risked hole distortion if the bits grabbed etc as it was 0.9mm gauge one of the features that the hydraulic press has which you could implicate in your hand one is a pair of flat bars that extend down to the flat bed where the die sits, these are used to hold the work down as the punch rises back out of the work piece, they dont need to be tight on the work pice so you can easily slide work in and out, they replace the spring idea you have which aids locating the punch on the steel also the punch section has a dimple point on the face rather than a sharp hollow, this also helps grab the steel work piece, where i did my 40+ holes i went one step further and pre drilled each one with a 3mm pilot hole, this was for quick accuracy as the hole punch then had a sure feel point to locate in and i didn't have to keep checking that part for alignment when handling large sheets of steel fine tuning its position can be a challenge but the pilot hole worked out great i also got a hydraulic/air foot pump so it made it alot easier to feed the work into position and punch the holes if you havent tried a plasma cutter for cutting long cuts on sheet steel its well worth it, on thicker steel the slag from the cut chips off very easy, on thin steel its not alot at all so i nip it off with a flap wheel on an angle grinder
Home from home to me as I spent over 70 years making press and all sorts of other tools.
That was great! Definitely enjoy this kind fo video - bring on more :) ohh, and a "spring cut" to make the spring fit 🤣🤣🤣🤣🤣🤣
thanks a lot for testing, I'm doing sheet metal processing (amateur based), and your video is filling up the missing gap. I'm going to do the same with a different shape punch within the next 1-2 months..
Very interesting video, that press is very nice and you did excellent work on it👍, makes want to get our hydraulic press finish up so can make some tools for it!
Impressive!
Testing is always welcome!
Mind? Why should I mind?? Love it! Les in UK
I do love me a fly press there's a big beautiful one where I work (when I get a van I'm going to try and buy it) I used to use one to straighten drill bits at my first part time job while at college and I've wanted one ever since
I've seen a computerised stamping machine, using combinations of standard sets of punches, produce all sorts of shapes. So it can actually be used in a much more complex way than one initially imagines.
Great teaching vid
love this content thank you
Great video. One suggestion, instead of welding the die into the holder, why not use set (grub) screws? Then holder could be used for multiple dies in the future, again I'm enjoying watching your channel. Thank you
The force of the press is determined by the screw pitch, and lever arm, I think. If you can get hold of an old car axle from a wrecker they're invariably going to be reasonably tough and somewhat hard. Case hardening is an option. Burnishing in the lathe to work harden (might not be all that suitable). Arc welding a blob of 6018 or 7018 rod onto the end and machining that back will be a harder face, although hard facing rod is obviously the ticket.
excellent thanks for the video
Thanks for an enlightening video. Some interesting comments from others too. Hopefully we'll see some further results in upcoming projects. Regards from Canada's banana belt.🤞🇨🇦🍌🥋🇺🇦🕊️🇦🇺👍
When I saw the beginning, I initially thought you would have the head of the punch cut at a slight angle (like how a syringe needle is cut to make it sharp, but not so sharp an angle) so one side of the punch would start penetrating before the other, or perhaps like an inverted "U" shape, so the "horns" at each end of the slot would be cut before the middle... don't know how well they would work, but if they did, wouldn't they reduce the workload?
You can buy 7 1/4" saw blades to cut Aluminum, Steel and Stainless now a days. The Aluminum blade works great, and I've cut 1/2" plate with the circular saw with the steel blade. The Stainless blade seems to dull fairly quickly. But the blades are really worth it and they have come down in price.
gREAT video. thanks!
Nice work 😍😍
Hey, old tool and die guy here, been machining and making tools for a long time 40+ die work not so long, kinda been around it for a long time but proper tool and die about 3 years, kinda a newby. Die clearance look in machineries handbook there is a formula. Steel, we use A2, stock punches come in D2, D2 is the best but hell to resharpen on big sections, A2 and we temper at 600f, work good for us. Why I started commenting was on hardness. The most used machine in shop after mills and surface grinders is our old Weiderman sp? turret punch which we punch holes in shims for dies, grind it down you have to shim it. Anyway, had a slow night and payed attention to the old girl, 3/8 punch was wrinkling shims .010 thick, inches that is, I am an imperial sort of guy but I am bilingual and can do metric. So I sharpened some punches and dies. The .375 die was hard, I knew so because I made it about a year ago, was amazed at punches, not that hard, stuck in lathe and turned gave a lick with stone, these punches have a centering tip to go into transfer punch holes. Almost soft as butter. We generally punch only brass stock, somebody had been punching 16 guage steel was the reason I was sharpening. Long winded but softer punches and dies will work for short runs but need to be harder than the material being punched. Story time again, I remember a big radius tool used in lathe, guy I worked with made one out of cold roll, kinda made fun of it but it worked well on that plastic.
Thankyou for the information. It will give me a good idea of the metal I need to look for for the die. Cheers
nice job
I worked with an industrial hole punch and it had a foot on it to stop the part from lifting when punch is extracted, retracted. It looked very much like a the foot on a sewing machine and had a dip down lever too just like a sewing machine.
I think you may be confusing area(the surface) and volume(the slug). Otherwise very good build.
I'd love to see you make a few different shapes like stars, ovals, triangles, etc. I think that would be a pretty cool project. You could also make a spring loaded release that uses 4 rods like that diagram you put up on the screen, except it only springs on the punch side and presses the material off. That'll give you a bit more control, and it will help hold the material in place while punching. There's nothing worse than the material moving on you right before the punch connects...been there and cussed up a storm when I had remake the entire part from scratch.
This would be really good for making just normal holes in sheet metal. When i do it i usually get really nasty burrs and the drill bit can wonder by a mm or more. With a punch setup you could rest the work piece against some pins in the die to create a line of holes that are really accurately positioned near the edge. You could also use the previous hole in a guide pin and space the holes accurately too.
Midnight oil post. The press worked great
You might want to consider adding a centring point to the punch in future ones so you can pick up a centre punch mark, the spring would get in the way though. All my round punches have them, and most of the square ones do as well. While I don't use them that frequently when I do use them for punching holes in sheet metal it sure beats drilling them, fast clean holes with no burrs to clean up.
Some random thoughts. I run an industrial CNC punch and shear. We buy all the punches and dies, so I will admit that I don't know the details of them all, but I look at them multiple times a day haha. For the punches they're just straight sides, no relief. While I think it's a good idea, I believe you're giving up quite a bit of strength doing so. Our punches also have a little "pip" sticking out of the center. Makes lining up by eye REALLY easy, though it'd be a pain to make in your case. The dies definitely need to be hardened. They actually provide most of the "cutting" action. You can tell. The punches can get dull and everything is decent. Once the dies get too worn it gets visible quick, misshapen holes, bigger burrs. As the others said, clearance, look for online calculators to figure clearance. Going from sheetmetal to that aluminum makes a big difference in clearance. There's lots of wiggle room obviously but if have too much it will make a big burr. Too tight clearance will make a lot more punching force. Good luck, and GOOD JOB
Many years ago I worked in a small company that made lapidary products.my work as a toolmaker was punching tooling, O1 tool steel was used for the punch and the die was cast from some low melting alloy cast around the punch as it wore down it was faced down on the lathe.these where used in a fly press,can’t remember what the alloy was called that was 45 years ago.
Thank you
Thanks!
Just for fun you might have a look at tooling for an ironworker (the fabrication shop machine). It’s somewhat standardized and the dimension drawings might give you some thoughts about how to make interchangeable punches and dies. You can buy these, obviously, including ovals and squares, etc., but I completely understand the desire to make them.
One idea for getting the material to come off the punch easier is to use a urethane stripper. basically a stiff urethane "spring" that slides over the punch a d compresses as the punch comes down. then the force of it returning it's shape pops the metal off. A lot of the older punch & die tooling I use at work has this style of stripper. Springs can work but usually need to be bigger and stronger which results in a dangerous amount of force near your fingers.
Thankyou, I think I have some urethane rods in strange somewhere. I’ll have to see if they are big enough for the job
@@artisanmakes it's worth trying. We use tapping oil to lubricate our punches usually so you should be fine with the oil you had. The only other note, our punches usually have a flat bottom face and a tapered neck. I don't know if that is better than a concave face or if it makes a difference at all. We punch mostly steel and sometimes copper with our big tools, occasionally brass with the small stuff.
Harden the die, the cutting corner if not hardened will blunt increasing the force required.
You really need a sturdier stand for your press. A lot of energy is being expended into the wobbling of the stand that isn't being transmitted into the press and thus your part. I expect you would find that it's 1/3 easier to complete the stroke.
Tip, put a slight angle on the face of the punch, this will reduce the force needed.
Very Cool, i have seen People use Transfer Punches for Round Holes..
Definitely consider hardening the die. Usually you’ll make a MS plate that bolts to the press with interchangeable hardened inserts for dies. Polyurethane makes an excellent stripper.
If you haven't already take a look at Make It Kustom, he does some very good videos showing his work especially with sheet metal forming.
Just my luck. I was working with sheet metal for the past three days and If I'd known about this DIY punch making It would have saved me a whole lot of time. The sheet metal I was working with wasn't very thick steel sheet, and I already have a one-ton arbor press in my tiny home shop. Oh well, now I know better. I wonder if the cutting action might be enhanced if the bottom face of the punch was angled just a tiny bit so that it's not perfectly flat. This way the force needed to start the initial piercing on the sheet metal would be more of a scissoring cut that a punch cut.
For sheetmetal, you could put a shallow V in the punch, take a look at round cutters made for conduit in sheet metal boxes, they operate with a simple bolt pulling them through. The slight V allows a shearing to take place gradually which lowers the force considerably compared to a flat surface.
Yeah. Look at "Greenly" or chassis punches. Also, the shear force is not area but perimeter. It is the length of the shear line not ALL the metal within the punched shape. When folding heavy sheet metal in a crude brake it helps to slit (stich) the bend line. Easier to fold and easier to keep true to the line.
Interesting video, thanks. They sell for a small fortune but you might want to look at the Diacro Model 2 punch press and how they guide the ram etc.. It's a 4 ton rated with 12" throat. There are a couple of adjustable legs that help with the stripping. You can also use urethane tube over the punch for stripping, similar to your spring. BTW, the punching force should be calculated from the cut length rather than the area.
This is a great video. and one that can be applied to any hydraulic shop press as much as you r fly press. The logic behind it all is perfectly sound. I spent a lot of time working in a production facility where we had big presses ( 200T while i was there but bigger now) right down to a cnc 20T turret punch press. Looking into the tooling for a turret punch press would go a long way to guiding you toward how you can make interchangeable tooling, how the punch / die / stripper arrangements work well together. Additionally rather than a stripper spring, since you have the ability to impose an upward force as much as you can downward force, a practical option is to have a dedicated stripper plate that you can bolt to your fly press. it will be more effective than the stripper spring, and you dont have to overcome the force of the spring to create the holes. There used to be a machine called a metal master which had a hydraulic punch system which had interchangeable tooling to achieve the type of holes you desire. The tooling used to be fairly inexpensive and perhaps getting one set could direct you down direction for future shop made tooling. One really great feature of these tools was a little pimple on the tip of the punch. this pimple allowed use of a guidance hole. for ultimate accuracy you can mark and drill small ( 3mm) pilot holes where you need your features, then you simply hold the sheet up to the punch as you bring the tool down, allow the pimple to line up into the pilot hole and every time you get the exact spot. For batches you make one template and use that to transfer dimples into all of the plates to be punched creating very high repeatability form a hand aligned process. www.machineryhouse.com.au/p202 This set for example could be suitable.
someone get this man a band saw good lord he is using a hack saw!
If you're doing a run of parts of the same thickness, you could make a mirror of the bottom die that the top retracts into to free the part
if you are only doing a few that are round...just take a drill of the right size and drill the die, then turn the drill bitaround, align and punch. Dremel the end of the drill bit with a small grinding wheel to sharpen it if you like.
Have you considered hard facing your punch and die? In oz you can get UNIMIG 3.2mm HYPERARC 531 Hard Facing Electrodes U63025 really cheap @ $20 for 1kg. It will give a HRC 55 surface but is not machinable, only grindable. I have used these electrodes on various projects as wear resistant surfaces with great success and makes it economical as you can apply straight to mild steel. Cheers Andy
"They told me there would be punch and pie!!" - Eric Cartman
Make a plate that overlays the top of your press with a removable center part that u can hold down with your t nuts. interchangeable an that way you can use 30mm steel as your dies that should keep cheap and easy to replace.