Dimple Dies Explained

Transcript

- Hi guys and welcome to today's gold webinar which is focusing on dimple dies. Now dimple dies are a common feature in motorsports and it's something that you'll see a lot around the paddock and in the pits and in many builds because as you'll see from today's webinar, they're quite easy to produce and with the right tools and the right processes can be a pretty simple modification that can save weight and add strength which is something that we're always focusing on in motorsports. So just before we get into that I just want to let you know that we'll be doing some questions at the end of today's webinar so if you're watching and you have any questions that you'd like me to answer on any of the topics today or anything fabrication related, then make sure you chuck them in the chat and I'll get to them at the end. So today we'll be focusing on dimple dies, the processes around them, the sheet metal removal methods and then showing you basically the tools that we have on the bench here, how they work and how easy it can be. Before we do that, I guess we need to answer one of the simple questions and what is a dimple die? So basically a dimple die is a tool that creates a hole and a flare like you see here.

So basically the purpose of this is to remove the weight via removing the material from the centre of the hole. As you probably know in motorsports the less material we have the faster we can go but we also need to keep the rigidity and that's why we add the flare on the outside of the hole and that's why we get this nice finish on our dimple dies and these are commonly seen in role cages and many chassis builds all through motorsport. Just before we go too far I want to show you my first time that I ever did any dimple dieing and this was on my 180SX drift car. As you'll see from this really short 14 second clip, this is the dimple die gussets that tie the B pillar into the main hoop of the roll cage. This was the first time that I did any dimple dieing and the first dimple die that I actually purchased for this process so I know a lot of you guys at home are probably looking at this stuff and thinking that's quite expensive and yes it is.

If we set ourselves up with a whole kit then these can range from around $500-$1000 USD which is quite expensive but you don't need all of them. Really in motorsports if we have 1 or 2 specific sizes then it can pretty much cover the majority of tasks that we're faced with so I would suggest going out and working out your hole diameter that you're looking to run and also remember that if we're building a roll cage then there are stipulations on the hole diameter for the gussets that you're using. So these usually range, the hole must be no larger than the diameter of tube that the gusset is reinforcing so if you're looking to do a roll cage in the majority of FIA sanctioned events, then most of our tubes are either 1.75 inch or 44.4 mm and 1.5 inch or 38.1 mm. If you get a dimple die that's 38.1 then you can use it for all of your gussets in that vehicle and that'll be perfect for that and many other jobs that you may be faced with. So without going too far into that we will obviously get into a demonstration today and I'll show you how to remove those materials and we can get into that.

So a dimple die, this is what it looks like, it's made of 2 halves, a die and a punch. So the female version or the female half is the die and the punch is the male half. So basically it has this flange that's machined onto it so when the 2 halves come together and sandwich the material, that fits in this centre hole, then it'll create the flare. So depending on the thickness of material that you're doing, this can either be done in a vice or with a hydraulic punch that we're about to do soon and that basically makes up a dimple die. These are made from hardened steel so they'll last a lifetime.

Most of the time these are chromoly or 4140 or any other high carbon steel so it's a really good idea, if you're leaving them in the toolbox or you have a set, make sure that they're oiled because they are a carbon steel and they will get rusty over time and the last thing that we want to do is introduce any contaminants into our materials when we're using this process. So that's a dimple die, what sizes are they available in? Well like I mentioned, you don't need all of them but a typical kit will come from something that is as small as this little guy which I think is around a half inch or 12.5 mm right up to this which is around 3 inches in diameter and in motorsports you wouldn't typically use something that's 3 inches in diameter so buying a full kit may not be specific to your needs so you can buy these individually or you can buy a smaller kit that'll have a range of dimple dies that'll suit your needs. So there are a few different dimple dies out there. These are either the radiused or the tapered version. So what we have here is a tapered version and what we have here, that is also a tapered version.

I'll grab a radiused version. So looking at these 2 parts, we have one that's a taper and one that's a radius. As you can see here, this is a radiused version and this is the taper version. What you get with these 2 parts is a different looking dimple die. The jury's out on which one's stronger because I guess the taper would have more rigidity but the, sorry the radiused would probably have more rigidity due to the material being flanged more than the taper but this is something that obviously we don't need to really understand too much because if we do dimple die something then it's going to be a lot stronger than not dimple dieing it and all and it really is up to you which one you use.

I prefer the taper just because it's a more classic look but the radius can be better for tighter dimple dies that require smaller holes and less of a flanged area on the outside. We do have to be careful when we're clamping these down because the process of clamping them will actually, if we're clamping some soft materials, if we're doing aluminium which we'll demonstrate in a minute you'll actually be forcing the outside surfaces onto each other. Now these are usually specified for maximum material thickness up to 3 mm thick. Anything above that you will be putting a lot of force on the dimple die's taper which may create wear over time. Anything smaller than that then what you'll be doing is you'll be clamping the outside of the material before the taper is clamping.

So you may not get the full taper on your dimple but this depends on the material thickness and of course we're not going to have a set of dimple dies that are machined specifically for a different thickness of material so these are all usually machined for 3 mm maximum and that's something that we have to just work with because obviously there's no point having too many of these things because they are expensive. So without too much rambling let's grab a punch and we'll start showing you how to create a dimple die. So a punch kit is basically again like our dimple die, it is two halves, we have the punch and the female version which accepts the punch and basically what this does is it removes the material that we need to first remove from our dimple die and this will actually create the hole that our dimple die can then be forced down onto. So before we do that we need to create the hole for the pull stud. So what I'm using today, and we can use a vice to push these dimples through, or we can use a pull stud that is attached to a hydraulic cylinder.

So if we have a look from above there this is basically a small hydraulic ram that uses a pull stud that is in a porta power type receiver here. So basically as we pump this it pulls the pull stud through and that will then relieve our material and create the hole in our material for the dimple die process. So just to give you a bit of an idea, we've got some aluminium here and I should have predrilled these holes because this is going to get a little loud. But what we'll do is we'll chuck some holes in this and run some dimple dies through. We'll do one on a taper and one on a radius and I'll show you the process of completing these and hopefully you get a pretty good idea on the process.

So I'll grab my safety glasses. So once we have our PPE which is basically our safety glasses we just need to create a hole and this pull stud actually measured 20 mm in diameter and to accept that we need to first put that into our part. Now this is just a bit of an explanation on the process so it's not vital that we keep this in the very centre but one thing to note that when we are dimple dieing our parts, our material does pull in for the flange and the flare so that if our dimple die is quite close to the outside of our part, one thing that you will notice is that the edge may not stay straight and it may be important to prepare the dimple into the part before we actually shape it. This can be something that we need to maybe pre do for our roll cage. Say if we've worked out a gusset and we've got a template and we've worked out our hole centres then we may do all of our dimple dies before we actually shape the outside to have a good fit on the material.

So first we just need to drill a hole in this and like I said, we just want to keep it in the centre so we've got a centre point there of 42 and to drill a hole I'm going to be using my step drill today. So this is a really good way of punching a 20 mm hole in something without having to go through a series of different drills. I don't have the luxury of having my pedestal drill set up here so we're just going to use the cordless. One thing I like to do with a step drill is use a multiple amount of speeds. Because we're starting with a 4 mm diameter hole.

I usually run this on speed 2 and then as we get up in diameter we, I like to bring this up to, or bring this down to speed 1. So the first thing that we need to do when we're working with a step drill is to identify which step is the diameter that we're working to. So here we have diameter 20 and I can see that via the markings on this. So I just want to put a little black line around here to identify once that punches through the material, then I know I'm going to be good to go for the pull stud to go through this aluminium. So while we're at it, I might do a couple of holes so that we can get a good idea and do a few more dimple dies.

We'll do a radiused and a taper so I can show you the difference in those styles. Before we do that, always lube up any drill that you're using. This may not be needed for obviously coolant reasons but it does actually make your drill last a long time and these things can get pretty expensive so that is important. So I've just punched through a hole here. So this is our smaller size first.

So as I'm going up in diameter, just want to change that speed back to 1. Keeping an eye... ...on when my 20 mm goes through. The larger the hole, the more torque our drill is going to have. So make sure that you're holding it nice and tight.

If this was a smaller material thickness then I'd probably want to wear gloves just to make sure that it doesn't rotate and cut me. This is actually 3 mm thick and aluminium that's been deburred so we don't really have that danger. Alright so there we have a 20 mm hole and before I drill the next one we'll punch this hole out. So one thing to note when buying a kit is that we want to match the punch size diameter with the dimple die diameter. So here we have a 51 mm hole which is 2 inches and we'll match that up with our 2 inch dimple die.

So first we need to put the female component onto the pull stud to run our 20 mm hole straight through here, I'll line this up so you get a better view from overhead. And then we can just wind on the male punch until it takes up the pressure onto the aluminium and then simply just pull this through. So basically as the pull stud's working its way through the material, it's cutting the hole for the dimple die to act on this part. So we just keep going until it's free and that is a very easy way to make a 2 inch diameter hole. One thing to note is you can use a hole saw for these.

It can get a little messy over time just because a hole saw likes to wander and then we may not get a perfect edge on our dimple die so these punch tools are really really handy and again you don't need a whole kit, you just need the specific ones that match your die. So once we have that done we can use our, release our die and sometimes the aluminium sticks in here which you'll need to remove the pull stud or grab a small hammer. Just to release the slug that's in there. So there is the component that is pressed out of the centre of the hole. Then we can take the punch off this and replace it with the dimple die.

So first up we will use the tapered flare. This is something that I think is a real timeless feature in motorsport. I think the tapered flare has just a good look about it and as you can see this is quite a large dimple die so we'll see how it affects the outside diameter of this material. So now this fits straight through the hole that we've just punched really neatly. You can take the sharp edge off that but we can also do this at a later date.

Sandwich the material in our little press here. Put the retaining nut over the top and then it's just a process of repeating the hydraulic ram through here so I might hold this up so that you can see this acting on the material as it runs through. So as we're pumping that you can see it closing up, you can see the aluminium starting to deform and it's not until these parts start to come together that the aluminium starts to flatten out. Now we don't want to go too far because it will bruise the material around the outside but we want to go far enough that it then returns that material flat because then we know that our dimple die has worked perfectly and basically that will allow us to have that nice flange on there and create some strength on that panel. So backing the pull stuff off, removing the component, there we have a completed dimple.

And you might see that I can look straight down the line and it's pulled a little bit of the material in around this area and this isn't such a huge problem but if you were working on something that needed a dead straight line then obviously leave a little bit of material so that you can file it flat later just because the flare here pulls a small amount in and we need to account for that. So that is the flared dimple die acting on some 3 mm aluminium, let's go ahead and we'll do the radiused dimple die in a 2 inch diameter to give you an idea of that process. Basically the drilling and the punching is going to be exactly the same so let's get that done first. Again we want to put some lube, this is multipurpose lubricating wax which I absolutely swear by, it's really good in motorsport fabrication because it keeps everything clean, you're not spraying coolant around and it only turns into a fluid when it gets hot so it's really good for protecting drills and I swear by it when hole sawing as well. So first we need to put this on speed 2 to get our small diameters ran through this aluminium.

Then once it starts getting into the larger ones, back it back to speed 1. Looking out for our... Looking out for the black mark on our material, on our drill rather. Like I said, it can get a bit grabby. There we have our 20 mm hole.

It is a good idea not to wear, you're probably thinking that I probably should have gloves on but it is a good idea not to wear gloves around rotating machinery. Especially those that we can't control because it is pretty common in fabrication that any loose clothing or any material can get caught up, any strands can get caught up in our drill or any rotating machines and actually drag us into them which again is not good for our safety so we always want to play it safe when fabricating. So now we set up our punch, pretty much how we did it before as well. Our 20 mm hole slides over the pull stud, the punch tightens down and we can run this through. Might hold this one up so you can witness the cutting effect that this has.

So keeping in mind this is 3 mm thick aluminium and really it takes no pressure at all, just to send this through. It makes holes very easy obtained. And there it's broken through. So I like to run it all the way through just to make sure that it's free. Back off the hydraulic cylinder.

And then separate... ...the two halves. And that can be stuck in there obviously 'cause that's the last dimple die that we'll use but this is a 2 inch hole and then we'll swap our dimple die onto the radiused edge. So as you can see here this is a radius rather than a straight taper. And one thing to note about these is they, when we line these up and we're doing multiple dimple dies in a row we need to leave enough room for the actual dimple die to have some space next to it.

So obviously when these crush down we don't want to be crushing the edge of the previous dimple die that we've created and this will allow us to have a series of dimple dies that all look the same. It might be pretty common, or I have seen actually a few fabricators that have taken the edges off some of their dimple dies so they can stack them a lot closer together and this is pretty common in motorsport fabrication when doing gussets for roll cages and things like that where you want multiple holes all lined up. So now we assemble our little pull together pull stud assembly. You don't need one of these, you can do it in a normal vice or a press or something like that but I just find these really handy to be able to just jump in, get the hole punched and be able to put this whole kit together because if you buy them as a kit you do save quite a lot of money and it really does make adding this hydraulic ram onto the equation quite a cheap and simple process. So I've put this in the wrong way.

This is one thing to note that we need to have all the dimple flanges on the right way. So I'll flip this over, run this down. We can get into bringing this through. So take up the pressure and you'll see that aluminium starting to deform. As that flange is starting to be pressed.

At this point this is where both the parts start to come back together and flatten out the material. Again we don't want to go too far and bruise the aluminium so a small amount of pressure, make sure the material's flat. Then back off this pressure, pull the retaining nut off the pull stud and there we have a radiused dimple die. As you can see that's quite short and sharp. And then we have our flanged dimple die or our tapered dimple die and this is quite a little bit larger and probably more visual.

Obviously this is aluminium so it's difficult to see the differences. But you can definitely notice on the back side that the round version or the radiused version is quite a lot sharper here which would require some sort of clean up or a little bit of a file or a deburr prior to fitting this onto the vehicle or welding it to something. Just so that when you're doing stuff on the back side you don't cut yourself or a line or something might be rubbing up against it so we just want to make sure that there's no sharp edges on that. So that is the process of dimple dieing and as I said you really don't need a whole kit, you just need a couple of sizes that are going to suit the project that you're working on but it is a really good idea to have a punch kit, have a hydraulic ram that makes doing everything in one position really easy and this can be great for doing roll cage gussets using a lot of dimple dies on aluminium for certain things like supports that might be in a cooling system, something that might be supporting an intercooler or really anything around the car for that matter. If we remove the material then we're creating a much lighter part and then by adding the dimple dies we're creating a much stronger part.

So usually if we remove this material from this part it would be able to bend quite easily but then by adding the third dimension from the dimple die, being it either radiused or tapered, then we create quite a strong and visually appealing part that pretty much screams motorsport so if you're looking to jump into this then it's a really good way of producing your parts, again removing some weight and increasing performance at the same time. So I think that about covers it all. The kit that I bought obviously ranges from that small half inch and I think I have 12 in total. This cost me $750 with the hydraulic setup. Again you don't need them all but it is really handy to have in the workshop.

That pretty much covers it and again if you've got any questions then throw them in the chat and I'll jump to them in a second and that's brought us to the end of the webinar. Remember if you don't get your questions answered on here then you can always jump into our forums and I'll jump on there and answer your questions. If you have anything or you even just want to upload the work that you're doing then it's always great to see you guys in there so jump onto our forums and ask any questions and I'll endeavour to answer them when I'm on there. Alright so I'm just going to refresh this page and see if we've got any come through. Sometimes this doesn't load up straight away but dimple dieing is something that I've had quite a lot of experience in and I'm just about to get into it in our roll cage for the S15 so it's something that is important in motorsport fabrication and having the tools to do it correctly, a drill to be able to drill out the diameter for the pull stud and then having a kit with the diameters that you require.

Remember if you're building a roll cage then you'll want to consult the rules for the diameter of the holes for your gussets and if you match the diameter of your dimple dies to those rules then you'll be able to use it all around the vehicle to great affect. Alright let's have a look at any questions that have come through, like I said the forums is a perfect place to do this so if you have anything then let us know. Alright some that have come through, does the depth of the dimple increase as the diameter does? Really good question yes it does. It's relative to the diameter and the actual width of the taper extends with the diameter of the dimple die. Let me visually show you this.

So this is I think a 2.5 inch and a 2 inch dimple die. That'd be even smaller I think that's 1.75 but the actual flange length is in relation to the diameter. This is something that we don't really get to choose, it's pretty much you buy a kit and that's how it is but it does extend out further in larger dimple dies so you will actually have a larger flange on that. Being a larger hole in the centre and then you'll have to space out each of these dimple dies a little further apart as we go further in diameter. So usually if we did have a really short amount of flat on this and if our taper did extend out even further then we wouldn't have the flattening capability that we need to then flatten out the part further and the edges may dig into our part and cause some unsightly marks around the edges which is really common when working with aluminium.

You can see some marks around here, this is just from the outer face flattening the material around and returning that dimple die or returning that panel to its natural state. What kind of edge margin determines the size of the die used? OK so this is edge margins, I guess you'd be working on how does it fit in the vehicle. So for instance if you're gusseting a roll cage then obviously this wraps around the tube and what we want to work with is enough margin on the edge to be able to clear the actual tube that it's reinforcing. We don't want this hitting up against the tube. So this is really relative to whatever you're working on but we want to make sure that we leave enough space for a nice weld.

We want to leave enough space so that we create enough room for the tube to wrap around inside of this. And if we're working with a flat bracket like this then we obviously want to create a margin on this so that we still have enough strength in the part. This will be relative to whatever you're working on but I wouldn't go any more than I guess the actual width of the outer of the dimple die itself. So if we're working on something like this sheet then what I would usually do and if I'm not bound by the diameter, I would usually grab my dimple die and I'd sit it on it and I'd say alright they're pretty much the same diameters or the same widths, let's use this size dimple die and that's going to give me a pretty even look and it's going to allow the part to be flattened, it's going to create enough strength through these areas and it's going to give me a pretty good looking dimple died panel but again we can thin that down if it's being welded to something as that weld is actually going to increase the strength of the panel overall. So we can go quite thin but just remember that we want to create the outer edge of the dimple die to be able to flatten the panel and otherwise we'd basically be moving it around too much and then when it comes to welding it we'd have to hand flatten it before welding.

How large of an arbour press would I need to use a 2.5 inch to 3 inch die? If we're talking about tonnage then you probably don't need too much. From time to time I've used a, just a normal what do you call it, a vice basically. Or you can use some clamps but usually a vice, give it a good yank and you'll be able to bring these dimple dies in together. One thing to note if you are using a die, I mean if you are using a vice you don't want to damage your dimple die so it's a really good idea to run some soft jaws on your vice jaws as they're usually made out of some hardened steel which is very similar to this. And you want to run some aluminium soft jaws on that vice so that we have a fair amount of coverage and we don't damage our dimple die.

And that will allow them to last forever and be scratch free. But usually a 5 tonne press or something like that will be ample for anything around 3 mm mild steel. If we're working with some chromoly sheet in 3 mm then this depends on the diameter of die. But if you're working on something that's around 2.5 inches then 5 tonne's going to be probably more than enough to create the dimple die. One thing I do love about the little hydraulic unit that I have here is that the centre spigot really aligns everything.

So once I drill my 20 mm hole I can put all the parts in together and everything is aligned central to that 20 mm hole. Always make sure that your hole is exactly central and doesn't wander around as you're drilling it because this will in turn not be able to be straightened up once you have the dimple die assembly all packed into the hydraulic punch. So if we get our drill right then this whole assembly will create a perfectly centered hole. What is the maximum thickness that can be used with dimple dies? Well even though they are machined for 3 mm thick, I think you can go up to 4, 4.5. I wouldn't go 5 mm thick steel in a dimple die, you're going to need so much pressure that it's probably going to start damaging the flare.

Because these are machined for 3 mm maximum then anything over that is going to put too much pressure on the actual flare of the material and can prematurely wear these. So we usually work on the rule in motorsports that 3 mm steel is pretty much the thickest material that you're going to need to run and this is backed up by roll cage regulations which stipulate that all footings must be 3 mm or above and usually that's the size of material that we would go the heaviest on any component in motorsport. Have you used 3D printed dimple dies? 3D printed dimple dies do exist, they are usually just a single 1 time use because they can crack. I have known people to produce 3D printed dimple dies and actually infill them with some heavier stuff like fibre glass for instance or resin just to make them last a little longer but you can 3D print these and if you're working on something like 0.8 mm mild steel then it is going to work. But obviously different designs and different printing methods are going to achieve different results.

I know that the carbon printing is quite tough and quite strong but these are prone to splitting but if you're working on 0.5 mm mild steel or something up to 1 mm aluminium then these can be quite effective. If you have a lathe or some machining capability then you can always make up your own dimple dies, these don't need to be exact to be able to get a really good flare and you can actually extend or decrease the amount of flare that you have on your dimple die to suit your project and store these away so that you can use them for future projects. That's actually how I got started, I was able to machine up my own and press some and really enjoyed the process of doing that because it allows you to really choose exactly what diameter you're using and how far the flare is and what angle the flare is. Should we debur the hole before running the dimple die? You can, you don't have to. Usually I prefer to debur it after it's done because this process usually brings out some of the grain structure in the material and will put a sharp edge no matter how far you debur it previous.

So this will give you a nice uniform finish and I'll just grab a deburring too now. So one of the tools that I use very often is this little rotating deburrer tool. So basically if we were to deburr this part I'd run this around and this is going to create a nice radius on my aluminium. The more times we run it around obviously the larger that radius is going to be. And there we have a nice smooth round hole that won't catch anything or won't tear into any hydraulic lines that might be backed onto this.

But you can do it previous but it's always good to do it after the dimple die has been created just to clean up that part and then I always recommend some scoth brite to clean up if you're welding it because usually our dimple dies have a little bit of oil on them and because they are high carbon steel then it's a really good idea to use oil on these. Both for storage and operation and if we're pressing our parts such as aluminium with these then we're going to transfer some of the oil onto our aluminium and if we're looking to weld that then we'd want to run it with some acetone and some scotch brite to get rid of any contaminants that are on that material and make the welding process a lot neater and cleaner. So deburring, cleaning and preparing prior to welding on your part. That's all the questions that we have for today. Again, remember if you have any more questions, then jump onto our forums and ask them there.

All of our other members can gain a lot of confidence and understanding by seeing all of those answers up there and it adds to the bank of knowledge in our ETS Fab forum so that's brought us to the end of the webinar, thanks for joining us and hopefully we can see you online again soon.