Flat dies vs. Dovetail dies?

[Ferguson]

I am back to looking at building a power hammer, probably a 35 pound "new Kinyon" style. I have good welding equipment and a small lathe, but no access to a milling machine.

My question relates to dies. As far as I can see, commercial hammers generally use dovetail dies. Flat dies seem more common for homemade hammers, especially treadle hamers.

With flat dies, what do people do for working stock down? I have seen one hammer with flat dies which used a "wedge" with a slight taper, set on the bottom die to facilitate making tapers.

I understand that flat dies are easier to use with spring dies, which makes sense. Some people have some provision for having spring dies drop into a square hole, so the spring die stays in place without one having to hold it.

I think that I have seen some examples of people using flat dies and then bolting on home made dies. The examples I have seen have the bolt holes on the top of the die, which means that the flat die has holes in it. I was thinking of putting the bolt holes on the side, but I imagine that there would be some disadvantages of that. Do people have hammers with flat dies and no provision to bolt on dies?

Since I don't have a mill, the dovetail dies might be impractical in that I would not be able to make my own dies. I like to make my own tools. So maybe I need to stick to flat dies just for that reason.

Pointers to useful web sites or previous discussions would be great, as I did not come up with anything in my own searches.

As an aside, what do people do to keep the bolts on their hammers from coming apart with vibration? Locktite? Wired bolts like on an old motorcycle? Tack weld the heads?

Thanks in advance.

Richard

[Dave H.]

Do you mean drawing dies? In general flat dies are better for general forging. It is much easier & safer to use flat dies when using tooling with your hammer. Power hammers like to beat themselves apart. Loc tite, lock nuts, castlelated nuts All will help but going over your hammer & checking them over before & during operation is the best preventive medicine. Don't be afraid to use lot's of Grease & oil. I prefer to lube with oil myself as oil will help flush grit & slag out of a bearing where as grease turns it into laping compound. Hope this helps.

Dave Huffman

[781]

Dovetail die is ussually how the for mounts to the anvil of the hammer. Flat or drawing OS the working surface. use flat with top tooling or spring does on the flats. WWW.umbaonline
.ning.com has clay Spencer fforging with a tire hammer and flat dies # rd105.

[Alan Evans]

With flat dies, what do people do for working stock down? I have seen one hammer with flat dies which used a "wedge" with a slight taper, set on the bottom die to facilitate making tapers.

To work stock down with flat dies you use just the edge of the die and starting from the tip feed inwards taking a little bit at a time so a taper ends up stepped, or ziggurat style. The die edges must always have a radius and it is this radius which has a fullering action. A light dressing pass will take out most of the steps and if you like the texture you can leave it at that or use a half round section flatter to smooth it further. The flat of the half round conforms to the taper and the half round top allows a straight blow. You use the flatter again starting from the tip of the taper up towards the thicker section, from thick to thin will always attempt to parallel the taper.

If you are in production making a lot of the same rate tapers you could have a fixed wedge, the half round flatter enables you to smooth any rate of taper.

I have also made up a series of fixed top tool taper flatters for small runs. I measure them by millimetres per 100mm so I have 4.5mm 6mm 7mm 10 mm and etc. the 6mm gives about 1/4" per 4" for instance.

I understand that flat dies are easier to use with spring dies, which makes sense. Some people have some provision for having spring dies drop into a square hole, so the spring die stays in place without one having to hold it.

I made up a frame which clamps around the bottom pallet and had a piece of 50mm (2") square tube which formed the socket and all the spring tools have a corresponding piece of 40mm (11/2"+) which drops in.

I think that I have seen some examples of people using flat dies and then bolting on home made dies. The examples I have seen have the bolt holes on the top of the die, which means that the flat die has holes in it. I was thinking of putting the bolt holes on the side, but I imagine that there would be some disadvantages of that. Do people have hammers with flat dies and no provision to bolt on dies?

I also made up some fullers which were held on top and bottom pallets with bolted lugs on the sides. The first couple of blows sheared off the bolts! so for 'mark two' I drilled the lugs out to 25mm (1") and cut off a slightly overlength piece of rubber hose which was compressed by the 12mm (1/2") bolt and washer and expanded out to fill the 25mm hole. This gave a shock absorption system and acted as an anti-vibration loosening system and works fine.

As an aside, what do people do to keep the bolts on their hammers from coming apart with vibration? Locktite? Wired bolts like on an old motorcycle? Tack weld the heads?

The only bolts I have had which kept shaking loose were on my 50kg Reiter (Kuhn) the hold down bolts and the access panel bolts would always be loose despite spring washers and nylocks, As per Dave H's advice just check them regularly.

[HWooldridge]

If dovetails and wedges are made correctly with proper taper and contact, they will often stay in place with minimal maintenance. I blued and scraped my wedges to fit the dovetails on my Beaudry and it doesn't take much effort to either seat or release a die. One or two swats with a 4 lb hammer will keep the dies in place and I seldom have to reseat a key - like most things, a little more work on the front end makes for less fussing with it over the long run.

[Bryce Masuk]

You could try the QC system like on a big blue, its nice to just be able to buy dies vs making them.

It would cost much more to have them made,
Although you can cut the taper and file it to finish what is your time worth?

Spring tools are good but they are never going to be the same as a set of dies

[Alan Evans]

Spring tools are good but they are never going to be the same as a set of dies

I guess it very much depends on the work and what size and sort of hammer you are using.

It is true the ideal would be to have a different hammer for each form of dies, to certain extent that is what I do, but the advantage of flat pallets and spring tools means that mid-heat you can swap to a different tool, you can't do that with fixed dies. On balance I find the flat pallets and loose tools more flexible/versatile.

On my 50kg Reiter I have only ever used a pair of cheese fullers with a drop on table. Could be dropped on and taken off mid heat. I used that system for ten years for virtually everything I forged. On the Alldays hammers 50kg and 150kg I have flat pallets and use either fixed spring or hand held tools in conjunction. I have made up some drop on specials which combine a series of tools and spacers for specific projects.

[HWooldridge]

Early in my career, I watched Clifton Ralph do his wonders with flat dies and slap tooling so I set out to emulate his example. My Beaudry has tall 4x7 dies and a clamp saddle to hold all sorts of spring tooling and I do not have any other dies. With that said, if all I was doing was drawing out and cleaning up fullered stock, then a set of half & half dies would probably be just fine but I make a wide variety of forms similar to what might come across an industrial smith's table so this setup is much easier for me than having a bunch of dedicated die sets.

[Alan Evans]

Early in my career, I watched Clifton Ralph do his wonders with flat dies and slap tooling so I set out to emulate his example. My Beaudry has tall 4x7 dies and a clamp saddle to hold all sorts of spring tooling and I do not have any other dies.

He certainly gave me a few pointers! Wonderful man!

With that said, if all I was doing was drawing out and cleaning up fullered stock, then a set of half & half dies would probably be just fine but I make a wide variety of forms similar to what might come across an industrial smith's table so this setup is much easier for me than having a bunch of dedicated die sets.

The only part I disagree with is the half and half dies. I think they are awful. A set came with my Reiter hammer and after an hours use and much cursing they have been on the shelf for the last 30 years! I hand ground my cheese fullers and they have not been off the hammer for the same period of time!

[Backwoods Blacksmith]

I use 1/2 13 allen head cap screws and lock washers on my dies. My main dies are flat 2 1/2 x 2 1/2 x 6 which I use with top tooling and form dies. I recently made a large radius profile set for free forming. My die plate is 1/2 x 6 x 6 and I use two bolts to hold it in place. Never had one come loose.
The dies are welded to the plate and heat treated accordingly.
No dovetails, no tapers and no wedges.

[peacock]

To get the most use of your hammer you need both flat and drawing dies. Without both it is like using only one face of one hammer on the exact same spot on the anvil and tring to do a variety of work.

[Ferguson]

Thanks to all for their comments.

Bruce M. invited me to visit his shop, where I understand he uses bolted on dies. I will try to post a photo after I visit, and also explain how he uses those dies, how or if he uses spring dies, etc.

Richard

[Ferguson]

I visited Bruce M., and looked at his system. He uses simple bolt on dies. He literally has 100 different dies. The simple bolt on dies can be easily made as needed, and changed quickly using a impact wrench. He does not like spring dies in power hammers, says that they are very noisy and tend to break. I am going to try to attach a couple of photos from Bruce's shop.

Bruce's approach made a lot of sense to me.

Richard

[Andrew T]

Bruce M, I like your system.
Care to share more photos or observations of your die setup?

[David Gaddis]

anyone care to speculate as to how I could apply Bruce M's system on a Champion 65

Thanks




carry on

[doc]

Dave,
Make male dove tails to fit your hammer, weld these dove tails to plates with drilled and tapped holes to accept your tooling (dies). Then install the plates with dovetails in your hammer so from then on all your tooling can be bolted on.

[macbruce]

anyone care to speculate as to how I could apply Bruce M's system on a Champion 65

Thanks




carry on

It's pretty simple, Sid Sudimeyer makes some upper and lower dovetail dies that are for recieving bolt on's for LG's. For mechanical hammers head space can be tricky and the dies like on the top shelf shown on my rack need to be shortened alot. A good example of that type of die(s) at work is on Rory May's thread; out the video on April 20.
The dies I use are the old standard Bullhammer 4 1/2'' OC. I mix it all up with spacer plates, adaptor plates and whatever my twisted mind can come up with as long as I can get the power to the hot metal.
I did dovetail/bolt on adaptors on two Beaudry's a #8 & a #2, I can still get pics of the #2 conversion.

[Judson Yaggy]

The Champions are a little different because the dovetails are 90 deg. to the long axis of the dies, so Sid's LG system is a good inspirational starting point but won't work in the Champion configuration. But Bruce and everyone's basic concept i.e. dovetail base with bolt on tops is the way to go.

[macbruce]

The Champions are a little different because the dovetails are 90 deg. to the long axis of the dies, so Sid's LG system is a good inspirational starting point but won't work in the Champion configuration. But Bruce and everyone's basic concept i.e. dovetail base with bolt on tops is the way to go.

I reckon any dovetail hammer can be converted, as long as the particulars of any given hammer are addressed correctly.

[macbruce]

On my very first thread here a few years ago I made the statement that ''dovetails suck'' and ruffled some feathers and wouldn't dream of doing that again...hehe. One of the rufflees said that he could change his dies way faster than me. Now I that race if it were run might be pretty close cause I cheat. Truth be known I don't care what system anyone else uses, It's more about being able to make the dies quickly than speed of changing them and that's a race DT's would loose for sure.

[HWooldridge]

This makes me wonder why the older hammer makers did not use bolted dies...maybe it was because dovetails were faster to make in the factory with a shaper/mill - or that cast iron may have had a greater tendency to break out at threaded holes - or was it something so simple as one maker choosing to use dovetails and everyone else followed suit? Really big hammers also typically have dovetails - is there some size range where they perform better than bolted ones?

[macbruce]

I reckon the larger industrial hammers that are produced even today never use anything but flat dies. Small fabricated utility hammers have been around a very short time and hammers like the Iron Kiss and the Blu hammers still use DT"S....to each his own.

[HWooldridge]

I reckon the larger industrial hammers that are produced even today never use anything but flat dies. Small fabricated utility hammers have been around a very short time and hammers like the Iron Kiss and the Blu hammers still use DT"S....to each his own.

Right - but it's relatively easy to make a solid sow block, plane the surface and drill/tap some holes. I'm just wondering aloud why dovetails got started in the first place.

[Backwoods Blacksmith]

wrought iron bolts and threads do not mix very well. dovetails were easy to cast. Only guessing

[metalmangeler]

I think both big blu and Iron kiss started with bolt on dies. I think the idea was that the dovetail were more solid and they are quick to change after you have the right wedges.