An interesting idea, Michael, but not applicable in this instance. Doing as you suggest would require boring out the existing 5/8" (approximately) diameter sockets I'm working with to accommodate the 3/4" Acme thread. These devices still need to mount on standard 5/8" photo baby pins. If the sockets were bored and epoxy filled to conform to the Acme thread, when attached to standard baby pins, the strength and integrity of the mount would rely totally on the strength of the internal formed epoxy Acme mold. Considering the potentially high value payload, I think only a tapped all metal socket will do. Thank you for the suggestion, though. It goes into the memory bank for future use.
-
Welcome back Guest! Did you know you can mentor other members here at H-M? If not, please check out our Relaunch of Hobby Machinist Mentoring Program!
How to cut internal Acme threads in a finished piece?
- Thread starter tetrode
- Start date
An interesting idea, Michael, but not applicable in this instance. Doing as you suggest would require boring out the existing 5/8" (approximately) diameter sockets I'm working with to accommodate the 3/4" Acme thread. These devices still need to mount on standard 5/8" photo baby pins. If the sockets were bored and epoxy filled to conform to the Acme thread, when attached to standard baby pins, the strength and integrity of the mount would rely totally on the strength of the internal formed epoxy Acme mold. Considering the potentially high value payload, I think only a tapped all metal socket will do. Thank you for the suggestion, though. It goes into the memory bank for future use.
Why don't you find a suitable roller cut off the end and make an adapter ....cheeessh and I'm unemployed :>)
http://compare.ebay.com/like/120841915337
http://compare.ebay.com/like/120841915337
Last edited:
Been there, done that:
The point of this exercise is to eliminate the need for an intermediary adapter (which may not be available when needed). By internally threading the baby receptor, the roller kludge, though effective, would not be needed.
As I mentioned earlier in this thread, there already is a commercially available, shorter adapter:
http://www.kaceyenterprises.com/?page_id=447
Again, the mission here is to try to make standard photo baby pin receptors dual purpose, 5/8" and 3/4-5 Acme, without the need for an additional adapter. I think trying to run a tap into the socket is what I'll try.
Just to give my 2 cents. I have cut many internal acme threads in my day. My thoughts are this. If the piece can be chucked in a four jaw or held in a fixture on a faceplate, I would cut a relief in the bottom of the bore the depth of the thread OD, make the most rigid internal threading tool possible, mount the bar backwards and cut the thread in reverse so the bar is cutting on the way out of the bore. This way you can put the tool in the bottom of the bore, set it to your depth , engage the half nut and cut on the way out without worrying about running into the bottom of the bore. Also if you set your compound at 13 degrees and use it to increment your depth you cut down on cutting forces considerably.
Unfortunately, no, I do not have a lathe which is why I asked if it might be possible to drive a tap of the required size manually. At this point, if I can find a reasonably priced tap, I'll give it a shot.
This is sage advice, I'm sure. However, you have to remember I am not a machinist and have neither the skills nor the equipment necessary to do as you suggest. Muscling a tap into an appropriately sized hole is really the best I can manage at the moment. If this proof of concept works out, it might be feasible to have a new baby pin receptor mold made that incorporates the Acme threads. If not, the part manufacturer may be able to sub out the thread machining step. We'll see. For now, I just need to cut the Acme threads in no more than four different pieces. Even one would get things rolling.
