Thread: Fly press tooling?

Hi Jordan,
As best I know they have always been custom made(except from a limited number of turret press tooling)
What are you punching the holes in? How many holes will you be punching?
Punches are easy, just buy some round HSS and make a holder for it.(limited number of standard sizes but grinding them down is no biggy if you know someone with a tool post grinder.
Dias wont be so easy but they dont need to be as good(depending on what and how many you are planing on punching.)

Stuart

Could Punch & Shear tooling be adapted? Don't know where to buy it though. I might be tempted to try making them. I'm sure you could find enough info online about materials, hardness, clearances etc.

Hi Jordan,
the latest copy of Model Engineers Workshop tells you how. If you don't have a copy or access to one let me know and I will sort it.

Phil

Hi Jordan,

If you just want to punch a few 5mm holes in light gage material. get a 5mm drill and turn it around and grind the shank end to a v shape with the low spot of the v in the middle, then grab a block of mild steel and drill a 5mm hole, now get a 6mm drill and drill from the bottom of the die to within about a mm of the top, so you have a relief for the waste to drop out the bottom.

I realise the instructions are a bit sketchy, but the critical things are provide clearance for the scrap to get out, and make the punch cut from the edges as you press down, (that was the v shape.)

If it's for a big production run in heavy material, then you might have to spend a few bucks and get the real thing in hardened tool steel.

Hope that helps.

Regards
Ray

To make the punch, you need a piece of 1/2" dia Silver Steel. This is machined down to 3/8" leaving a 3mm thick head at the end. the 5mm dia. is flared into the 3/8" dia. with a generous radius. It is absolutely essential to have no sharp corners or turned "rings" on the pin itself or the flared section. The length is dependent on the setup you use and the thickness of the stripper plate. I certainly would not use HSS for the punch, this is too dangerous if you have had no experience with press tools. The Silver Steel will make an excellent punch and will last a long time.
The dies are very easy to make as well. Use a mild steel plate about 1" thick, machined on both sides. Bore a hole in one side (the top surface) about 3/4" dia or 1" dia and about 1/2" deep. Drill a 1/4"- 5/16" hole thru the center. Make the die from Silver Steel using a piece finished to the same depth s the hole. Drill a 5mm hole all the way thru the center. Now, take a suitable taper pin reamer and from the underside of the die, run the reamer in until there is a parallel section left at the top of the die. This section needs to be about 4mm or 5mm in length. The taper ensures there is clearance for the slugs to fall out and pass thru the die-set. Harden and the punch and die and quench in water. Temper them back to relieve the brittleness and then assemble them in the press. The die needs to be a firm fit into the block it is mounted in. The punch needs to have a head turned on it so that it won't pull out of the top mount when the stripper plate is pulling the sheet metal off the punch. Polish the punch after hardening and tempering and grind the end flat. The die is also lightly ground on the top to produce a sharp edge.
The punch needs to have clearance in the die, this clearance should be between 3% to 5% of the thickness of the material being pierced. If there is no clearance, the punch will snap and the die will wear away. If you want an exact 5mm dia hole, make the punch 5mm dia. and enlarge the die to obtain the required clearance. If you would like a drawing of this set-up, I will provide one for you. All the above can be made quite simply on a lathe. Any common high carbon tool steel can be used for the punch and the die. Scrounge around at any tooling engineers workshop if you can. Try and identify the steel so you can properly harden it but don't use an air hardening steel if this is your first attempt at making this tooling. Contact me here if you or anyone else needs more info.
Kody

(Toolmaker/Machinist by trade)

Hi Kody,
Just what might happen to HSS in a flypress?
What do you think Jordan is punching a hole in? 3%-5% sounds way to tight to me.

Stuart

Originally Posted by Stustoys

What are you punching the holes in? How many holes will you be punching?
Punches are easy, just buy some round HSS and make a holder for it.(limited number of standard sizes but grinding them down is no biggy if you know someone with a tool post grinder.
Dias wont be so easy but they dont need to be as good(depending on what and how many you are planing on punching.)

Stuart

Thickness of workpieces is 4mm, mild steel. Potentially, hundreds of holes so punching them out instead of drilling seems a better alternative if possible.
HSS round does seem obvious choice for the punch but the more tricky part is the die.

Jordan

Originally Posted by Steamwhisperer

Hi Jordan,
the latest copy of Model Engineers Workshop tells you how. If you don't have a copy or access to one let me know and I will sort it.

Phil

Thanks Phil. I'll see if I can get one from the newsagent.

Jordan

Originally Posted by RayG

If you just want to punch a few 5mm holes in light gage material.

Actually, possibly many holes and 4mm MS material, so something more durable is indicated I think. I get the principles you've kindly outlined.

Jordan

Originally Posted by Kody

To make the punch, you need a piece of 1/2" dia Silver Steel.

(and lots more detail)

Kody
(Toolmaker/Machinist by trade)

That's a great summary, well described thanks Kody.
I have some 1 inch thick mild steel, but need to get hold of some 3/4 inch hardenable stuff for the die.

Could HSS for the punch shatter dangerously?

Jordan

Hi Jordan,
HSS is notorious for shattering when used as a small hole punch. It often disintergrates and the small pieces fly out with great velocity. These small pieces can do a lot of damage to you similar to a bullet. You "might" get away with using HSS but I would never even consider using the stuff. The second problem with HSS is shaping it to the desired dimensions. Silver Steel would do the job very well for you. If you can find some, you could use a high carbon tool steel called "TOH" but there are many others that are equally as good. Keep the actual shank of the "pin" as short as possible. A suggested length is as follows. 4mm material thickness + 5mm Stripper Plate thickness + 5mm = the total length of the "pin". This equals 14mm or no more than 15mm. From this point, the punch is flared out to 3/8" plus the head on the end. The extra 5mm will allow for sharpening of the punch but this extra length should be kept as small as possible. Even 2mm would be better and simply make a new punch when needed. It is very easy to change the punch when made as I described it. Entry into the die need be only 0.3mm but no more than 0.5mm.
Punching 4mm thick ms, a clearance of 4% per side would be a very good staring point. This equates to 0.157" ms plate being punched and 4% of 0.157" = .006". Therefore make the punch 0.012" smaller than the die or conversely, make the die 0.169" dia. The dia. of the punch will be the dia. of the hole that it makes. Too much clearance will produce a torn hole that is rough and ragged on the bottom. Too small a clearance will overload the punch and it will break. Are you punching the holes in a strip or in single parts? Single parts or a long strip will need special modifications to enable the parts to be passed thru/across the die if a high production run is required. A stripper plate is an essential part of the tooling. The complete assembly is best made using a standard die-set. This looks like two solid cast iron plates with two pillars at the ends. These pillars are essentially slides that maintain correct alignment of the punch and die. After setting the die and the punch in the exact position, the parts are carefully doweled to maintain alignment when maintenance on the parts requires disassembly of the parts.
Good luck with your project, feel free to contact me if you need further help and for when you are heat treating the punch and die. Please stay away from HSS for this project.

Kody

Originally Posted by nadroj

Thanks Phil. I'll see if I can get one from the newsagent.

Jordan

Hi Jordan,
it is issue No. 184. It's not out yet, I subscribe so get them a couple of months early.

PM sent

Phil

Hi Kody
Can't say I've had a HSS punch shatter, not that it would have mattered(given the design of the machine), I haven't heard of it and google isn't much help either. But I'm talking about HSS tooling made for punching, given the normal end user has no control over the temper of HSS I'm happy to believe it could happen. But of course tool steel punches not tempered correctly would do the same.
There should be no need punch entry into the dia at all. Why do you say 0.3mm?
I dont recall hearing die clearance ever been called "per side"(at least on a round punch/die), but I guess that might be a "tomato,tomato" thing. 8% still seems a little on the low side, I would have thought somewhere between 10 and 15%
You want a die set(with their expense and limitations, ok they have a couple of advantages as well) to punch what a present seems to be a few hundred holes in a fly press?(assuming of course the the flypress is well adjusted and up to the job) Unless he has a spare die set laying around thats going to get pricey.

Stuart

There are some die sets on Ebay at the moment, item 120818027458
They seem to be for a particular shape. Can they be adapted? There is no separate removable die visible - the shape is made in the bottom plate directly by the look of it.
Being hardened, it'd be a job to alter it I think?

Jordan