Hi All,
I'm sure there is a joke in the title somewhere, not too sure about these things.
I make a part where it requires a 1-1/2" NPT female thread in silicon bronze, it REALLY tough stuff with about 30% the machinability of steel. 4130/4140 is easier to machine than this for reference, at least from my experience.
I've used brute force a number of times, raw torque, bore the hole, taper ream the hole to size, and skip tooth tap. Regular tap will not work. I made a special "tap holder" from 2" hex stock, and use a 2" box wrench as the tap arm. It will stall a 7.5HP lathe in the lowest gear, it's just raw torque. It's really a hard way to do it, hard on everything, not to mention me. It's stressful to do that way.
So we send them out to a machine shop, over the year we do about 500 pieces, batches of 75 or so at a time. $20 a pop and they do good work. The problem is they are going out of business, and it's a good time to look at options. They single point thread it on a CNC Mori something. I cannot buy their machine, and it will not fit in my shop. A little tight for space, not an option.
So I'm looking at options.
Currently the best idea is to CNC retrofit a spare Bridgeport and thread mill it. I have the Bridgeport (bought it from the shop), done plenty of CNC retro's in the past, very comfortable with it. It will fit in the budget, less that what I spend to send them out now. Plus I get a fun CNC mill to do some other small chores here and there, CNC mill is a handy thing to have around.
But of course it's sometimes good to hear from others, If I convince myself this is the ONLY solution, we all knows how that goes. I don't want to drink my own kool-aid.
So can anyone think of a better option CNC retro a mill and thread mill this large 1-1/2" NPT in silicon bronze? for under about $8K?
All good ideas welcome.
Thanks in advance.
Aaron
I'm sure there is a joke in the title somewhere, not too sure about these things.
I make a part where it requires a 1-1/2" NPT female thread in silicon bronze, it REALLY tough stuff with about 30% the machinability of steel. 4130/4140 is easier to machine than this for reference, at least from my experience.
I've used brute force a number of times, raw torque, bore the hole, taper ream the hole to size, and skip tooth tap. Regular tap will not work. I made a special "tap holder" from 2" hex stock, and use a 2" box wrench as the tap arm. It will stall a 7.5HP lathe in the lowest gear, it's just raw torque. It's really a hard way to do it, hard on everything, not to mention me. It's stressful to do that way.
So we send them out to a machine shop, over the year we do about 500 pieces, batches of 75 or so at a time. $20 a pop and they do good work. The problem is they are going out of business, and it's a good time to look at options. They single point thread it on a CNC Mori something. I cannot buy their machine, and it will not fit in my shop. A little tight for space, not an option.
So I'm looking at options.
Currently the best idea is to CNC retrofit a spare Bridgeport and thread mill it. I have the Bridgeport (bought it from the shop), done plenty of CNC retro's in the past, very comfortable with it. It will fit in the budget, less that what I spend to send them out now. Plus I get a fun CNC mill to do some other small chores here and there, CNC mill is a handy thing to have around.
But of course it's sometimes good to hear from others, If I convince myself this is the ONLY solution, we all knows how that goes. I don't want to drink my own kool-aid.
So can anyone think of a better option CNC retro a mill and thread mill this large 1-1/2" NPT in silicon bronze? for under about $8K?
All good ideas welcome.
Thanks in advance.
Aaron