mklotz
Well-Known Member
My first machine tool was a Unimat and, while I've gone on to larger equipment, I still use my Unimat as a dedicated miniature milling machine and precision drill press.
To that end, I made a number of modifications to the machine to make using it easier.
I added a 3/8" square rail parallel to the spindle on the wooden base. An adjustable bracket can be slid along this rail. It carries a 2" DI that allows measurement of the carriage position.
Said rail also carries an adjustable bracket to which is fixed a 1" DI for measuring cross slide motion. This bears on an elongated aluminum jaw fixed to the vise which is mounted on the carriage. (The rounded castings don't provide flat reference surfaces - hence the elongated jaw.)
Sitting in front of the base are two important accessories. The one closest to the base is a length of 1/4" stainless rod. It can be slid down the spindle, emerging from the opened chuck. On one end is a conical point for centering holes. The other end has a turned 0.2" precision tenon used for edge finding.
Aside: For those not familiar with the Unimat, it has very little spindle travel - about 0.6". Furthermore, the support column is round and unkeyed so, if you raise/lower the power head you lose all registration. Hence the need to do tooling changes via the aft end of the spindle once the head is located.
In front of the locating rod is a thin rod with a magnet at one end. This is used for tooling changes once the spindle is locked in place. A drill/mill/rotary file is attached to the magnet and lowered into the spindle until it emerges from the chuck. The chuck is then locked onto the tooling and the magnet withdrawn. Reversing the procedure allows the removal of tooling via the aft end of the spindle.
On the top of the column that supports the motor/spindle assembly I installed a fitting that supports another 1" DI used to measure Z motion of the tool. This DI bears on a piece of square aluminum tubing clamped to the pulley support bracket
In this view you can see one of the clamps that secures the square aluminum tubing. An identical clamp is out of view on the other side of the pulley bracket.
The motor/spindle assembly is rather heavy and adjusting it side-to-side is somewhat awkward. I made a substantial clamp that mounts to the motor support column and bears the weight of the assembly while it's tweaked side-to-side around the column. This also works as a safety feature preventing an accidental drop of the motor/spindle onto a delicate workpiece.
Once the spindle is properly extended for milling, it needs to be locked in place. On the original machine this was done with a SHCS that needed an Allen wrench to tighten - very awkward when doing precision work. I replaced the SHCS with an extended locking handle that requires no additional tooling be juggled while making adjustments.
The final improvement is electrical. As delivered, the Unimat has a switch mounted inline on the power cord. Another bit of awkwardness. (I guess the Austrians just don't know or care about ergonomics.) I took a 10 amp relay and wired a receptacle through it. The low voltage relay trigger contacts are brought out to a jack into which I can plug a (low current) foot switch of the type once used on dictation machines. Perfect for Unimat control, it can also be used to control other, larger power tools. It works a treat for the Dremel.
To that end, I made a number of modifications to the machine to make using it easier.
I added a 3/8" square rail parallel to the spindle on the wooden base. An adjustable bracket can be slid along this rail. It carries a 2" DI that allows measurement of the carriage position.
Said rail also carries an adjustable bracket to which is fixed a 1" DI for measuring cross slide motion. This bears on an elongated aluminum jaw fixed to the vise which is mounted on the carriage. (The rounded castings don't provide flat reference surfaces - hence the elongated jaw.)
Sitting in front of the base are two important accessories. The one closest to the base is a length of 1/4" stainless rod. It can be slid down the spindle, emerging from the opened chuck. On one end is a conical point for centering holes. The other end has a turned 0.2" precision tenon used for edge finding.
Aside: For those not familiar with the Unimat, it has very little spindle travel - about 0.6". Furthermore, the support column is round and unkeyed so, if you raise/lower the power head you lose all registration. Hence the need to do tooling changes via the aft end of the spindle once the head is located.
In front of the locating rod is a thin rod with a magnet at one end. This is used for tooling changes once the spindle is locked in place. A drill/mill/rotary file is attached to the magnet and lowered into the spindle until it emerges from the chuck. The chuck is then locked onto the tooling and the magnet withdrawn. Reversing the procedure allows the removal of tooling via the aft end of the spindle.
On the top of the column that supports the motor/spindle assembly I installed a fitting that supports another 1" DI used to measure Z motion of the tool. This DI bears on a piece of square aluminum tubing clamped to the pulley support bracket
In this view you can see one of the clamps that secures the square aluminum tubing. An identical clamp is out of view on the other side of the pulley bracket.
The motor/spindle assembly is rather heavy and adjusting it side-to-side is somewhat awkward. I made a substantial clamp that mounts to the motor support column and bears the weight of the assembly while it's tweaked side-to-side around the column. This also works as a safety feature preventing an accidental drop of the motor/spindle onto a delicate workpiece.
Once the spindle is properly extended for milling, it needs to be locked in place. On the original machine this was done with a SHCS that needed an Allen wrench to tighten - very awkward when doing precision work. I replaced the SHCS with an extended locking handle that requires no additional tooling be juggled while making adjustments.
The final improvement is electrical. As delivered, the Unimat has a switch mounted inline on the power cord. Another bit of awkwardness. (I guess the Austrians just don't know or care about ergonomics.) I took a 10 amp relay and wired a receptacle through it. The low voltage relay trigger contacts are brought out to a jack into which I can plug a (low current) foot switch of the type once used on dictation machines. Perfect for Unimat control, it can also be used to control other, larger power tools. It works a treat for the Dremel.
