Here is another post about my interchangeable tooling upgrade. I bet you lot are getting fed up seeing them, but as far as I am concerned they have got to be done, and I may as well show you what I get up to rather than stay quiet.
So this is what I am replacing this time, the MT adapter with a Myford nose on it.
As I have mentioned before, these have kept me going for a while, but I am just not happy with some of the surface finishes I am getting due to lack of rigidity. I just don't like cleaning up machining marks.
This big blue lump is what I am going to make it out of. Ralph gave me a long length of this stuff, I have a feeling in the back of my mind that it is cast iron, but I am not sure. I think it is an end of day pour and everything left over got chucked in the pot. You can just see a light patch on the cut face. This is a counterbalance weight off a garage door and they just stuck a length of bent rod in the casting box to make a hanging loop, that is a bit of the steel rod.
But this doesn't have to withstand massive forces, so it will do.
The lump was mounted into the 3 jaw and I attacked the hard outer skin with a pair of roughing tools. The skin must have been around 1/16th of an inch thick, but once the tool got under it, it came away fairly easy. I am preparing the metal here for all the following machining operations. I have created a main datum bottom face and a perfectly square side to it.
The centre hole was then drilled and fine bored to accept a close tolerance fit of the MT locating spigot. The spigot had previously had a non tapered area machined on it. It is that close fitting machined end and this bored hole that will align the adapter perfectly central on the RT. So that is all the datums produced to close standards. Now I had to make sure that everything else was square to these datums.
Out came the soft jaw chuck.
I love working with soft jaws, because if they are used correctly, your accuracy and concentricity of parts takes a massive leap forwards, and for stuff larger than normal collet work, knocks four jaw working into the shadows, because it is so easy to do.
With the jaws tightened down onto a bit of stock bar, the jaws are gently bored until you can just fit your turned part into the made recess.
Once that stage is reached, the barstock is removed and every burr on the machined area is dressed down and inside the jaws are cleaned up spotless.
The datum faces can now be clamped up in the soft jaws, and gently bedded into the recess.
You can now work with confidence in the knowledge that anything you machine up outside the jaws will be perfectly square and concentric to the datum areas.
The part will not be removed from the chuck until every machining exercise is completed.
The roughing tools were brought into action again, and they soon got rid of the tough outer skin and a lot of the bulk on the part.
Then everything was turned up in preparation for single point cutting the thread.
The threading and other size getting machining was carried out, then I bored down to meet the previously bored hole. but this time it was about 10 thou larger in diameter. I had drilled and tapped the end of the locating spigot, and by feeding a bolt down this hole, I can remove the spigot if I need to hold a bit of long rod in the chuck, this will allow me to hold a rod over 6" long down in the RT.
This shot shows the locating spigot in position and the new backplate with threaded nose.
This is how it will fit together.
The backplate just needs four holes drilling and I need to make up the t-nuts and bolts. Because these have been shown how to do before, I am classing this post as finished.
I have visitors tomorrow (Madmodder members) and I will be having my new computer delivered as well, so those two little jobs still to be done will have to wait until another time.
Bogs
