Hi! I am in need of advice regarding a fly press that has no stop on top of the screw to make it stop at the desired point. Can you please give me an idea on how to solve this? 

Will a split collar for hydraulic cylinder put on the screw work? Or will it damage the screw?

Don't know the size of the press but the screw diameter  is 60mm (about 2.36 inch).

We have a section devoted to presses, I will relocate this there

My screwpress has a knob to hold it up at a certain place but I know of no press made with one that stops going down at a certain place---severe stresses on the system!  I use a stop block of the correct size to stop the ram going down at a specific point.

I've only used one screw press (in Latticino's shop), but that one had an adjustable depth stop so that you couldn't over-press your workpiece. For example, you could set the minimum distance between a set of fullering dies at 1/4" and fuller down a long section without any risk of squeezing any part of it too thin.

This was adjusted with a knob on top around the spindle, but I can't remember if that adjusted the whole screw mechanism up and down, or if it had a movable stop that limited the ram's travel. Either way, it was pretty awesome.

Also, welcome to IFI! If you haven't yet, please READ THIS FIRST!!!

That's what i'm talking about. An adjustable depth stop. They usually have it on the srew, it's a split collar that also has threads. The screw having on the top portion smaller threads on top of the big ones. I could use a block under the ram for a stop but it's really unconvinient and not really adjustable unless you have a lot of  blocks in different sizes. 

Thanks for the welcome!

My made in India 5 ton has just the setup that you have described - A fine-pitch (10 TPI) thread is cut into the major diameter of the big screw.

A split collar would work, but not as a HARD STOP. Your press likely has enough power to DAMAGE itself at your hand.  Even though mine appears to be intended as a Hard Stop, I would first add a heavy spring washer to decelerate the ram.

If someone has a different experience with this, I stand ready to update my knowledge base.

Hope this helps,

Robert Taylor

Not the best illustration, but here it is:

Robert, that is indeed a hard stop. 

Both of my flypresses have them.

OP, sorry about the inconvenience but if you don't have a collar stop on the screw, you must resort to kiss blocks

Ok, I understand. I'll make some kiss blocks. Thanks all for your answers! 

Greetings Mihai, 

       Another solution is to cut thick wall pipe for depth control in place of the collar lock . Split the pipe in half than a simple hose clamp will hold it together. Doing it this way the kiss block will not get in the way I the work. 

Forge on and make beautiful things 

jim

A lot depends on if you are using the screwpress to bend stock but not change it's cross section or if you are planning to change its cross section; or if you are using it to drift and want to stop at a certain point... The way I often use mine is to spin it down as fast and hard as possible; as the toroid is several hundred pounds (couldn't afford a small one had to settle for a large one!) It has a lot of umph to put into deformation and so kiss blocks work for me and pipe wouldn't. 

Now a friend of mine has a similar one, and a larger electromechanical one and finally got a knuckle press...for coining...see www.shirepost.com/blogs/news/how-a-fantasy-coin-is-made  to see several of their presses

When I drift I want to be able to stop at a certain point. Pipe might work. I will try. Thank you! 

On 2/19/2019 at 9:52 AM, arftist said:

Robert, that is indeed a hard stop. 

Thanks, arftist.

I have not had time to do any actual work with my press - Still working and living out of town. I did get to set the stop and slam it down a few times - seems OK, but there is a lot of garbage at the interface between the two threads. Needs a serious deburr job. I will eventually pull the screw out to finish it proper, and sample its properties.

I will be a bit leery until I ascertain the toughness of these features.

Robert Taylor