Hard to tell from the pics but the thread pitch makes them look like a screw press instead of flypress. So if you bid on them make sure you double check the thread pitch and how many starts.
Well, they are actually listed on ebay as screw presses. I guess I thought a screw press and a flypress were the same thing. What is the difference? Screw pitch? What does "how many starts" mean? I'm flypress/screw press illiterate!
Walker
walker Wrote:Well, they are actually listed on ebay as screw presses. I guess I thought a screw press and a flypress were the same thing. What is the difference? Screw pitch? What does "how many starts" mean? I'm flypress/screw press illiterate!
Walker
A screw press was designed for jewelry work where little head travel was needed. Therefore the threads are finer and you would have to move the handle more to get more travel. ACME threads have different starts. A start is basically how far the screw will travel in one revolution. This is important for a flypress because you don't want to have to swing the handle in front of your face to get the travel you need.
walker Wrote:...What is the difference? Screw pitch? What does "how many starts" mean? I'm flypress/screw press illiterate!
Walker
Screw starts is how many independent threads on the screw. Pitch is the distance between threads. Lead is the amount the nut moves in one revolution of the screw. (or I guess in the case of a flypress, how much the head moves in one revolution of the handle). For a single start, lead is the same as pitch. For multiple starts, lead is pitch * starts. See
HERE for a good explanation and pictures.
Shawn,
Nice explanation of multiple start threads. On the internet groups there is always someone trying to build a flypress, without understanding the idea of the multiple starts giving you the acceleration that makes the whole thing work when it comes to the sudden stop at the bottom.
Now's where that sophomore physics text: mass, acceleration, force, etc.? Welcome back from vacation, you were missed; Duck almost didn't play nice a couple of times.
Dave
I have a flypress similar to the ones listed in the first two links....in fact mine says adams brothers on the cast table and on the press itself is listed reynolds tool sales (which is now rice machinery in providence RI)
the screw in my press is a 4 start thread. I used many like it when I worked at speidel and they were common in the jewelry industry. I'm not sure how long of a stroke it has on it....its been sitting in storage pretty much since I got it about 1997 (for free). I originally offered to give it to a friend.....he said hold onto it and told me about the uses in blacksmithing. I wasnt into smithing at the time and I'm just really starting to get into it.
I have photos of my press posted at Iforgeiron.com along with tooling I picked up where I work now. I'm heading over to the storage place now to pull the head out of it. the hole in the ram for the tooling is either 13/16" or 15/16" and I'm going to try to find a machine shop to bore it out to 1" so I can use some of the tooling I have now.
http://www.iforgeiron.com/gallery/showga...puser/2172