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Unimat 3 Pillar Drill

I really want a small pillar drill that is available for use on a regular basis. I have a Unimat 3 lathe/mill, but whenever I want to use it as a drill it is normally configured wrong and so lots of messing around. At this point I normally resort to the much larger milling machine and this is just not delicate enough for 2mm drills.

So for some time I have been looking at the Universal Pillar Drill that you can buy as a set of plans and castings. Then I thought why not buy another Unimat 3 post and drill attachment and make it into a permanent drill.

Review / Make

The drill purchased for 95 including postage on ebay - August 2014

Very few marks on the post or the head. Also, no play in the bearings.

This was a stunningly good buy for the price.


There is a separate fine feed that can be fitted to this head if you want to use it as a milling machine. For this particular use I don′t think I need it.

The first task is to build a nice sturdy base. My idea was to build the base from a wood sandwich.


Home made captive nuts tapped 6mm to tack the caphead bolts that fix the bottom end of the pillar.

As you can see here I applied slow setting 2-part epoxy to the nuts.


This shows the nuts from the other side before I pulled them through and slightly proud.

The nuts are in one of the oak layers.

The layers of oak and mahogany all glued together to form a substantial base.

This is looking rather rough at this point and quite a lot of machining was needed to get this into a better shape so that I could then mark out a nice plan form.


The captive nuts that were shown earlier you can now see are slightly proud of the wood in which they sit.

The "V" shape is a nice form to pull the pillar into. This was a bit hit and miss, but the wood is soft compared to the steel pillar and so you can adjust the bolts to pull the pillar into position.


I sanded the base and then gave it 2 coats of plyurethane varnish. The pillar attaches perfectly and forms a nice looking stable and solid base.


The next step is to form the part to support the table. For this I found a piece of aluminium that had been cut from a round.


I machined this table from a 1/2" thick slice of mild steel.

I quite often mark out using a permanent marker to colour the metal plate, wait for it to dry and then scribe. This is much cleaner than engineers blue and you get a very nice regular surface to scribe.

The centre of the table was threaded 14x1mm - the headstock/tailstock/drill head thread of the Unimat 3.


8 slots were machined in the table 6mm wide so that parts or vices can be bolted down if required.

After some machining the table was threaded onto the support spigot and slotted into the bracket.

As this image shows the table is quite large for the size of the drill, makes for an easy surface to work on.


Whilst machining the arbor for the plate I thought it would be worth engineering an indexing system that would allow me to effortlessly, but accurately drill the fixing holes for cylinder end covers etc.

I used the Hobbymat lathe with the Unimat milling head to index and make the holes 6, 8 and 10 in three rows that would allow me index combinations of: 2, 3, 4, 5, 6, 8, 10


The 14x1mm thread allows me to fit Unimat chucks etc to the mill and so easily hold parts for indexing - this is just a practise part that I drilled 6 evenly spaced holes in.

The piano wire for the indexing is ok, but is a bit flexible and not that elegant. I will replace this some time soon when I think of something better, maybe just another piece of piano wire with a neater bend.


Now with the aluminium table support powder coated in white the drill is really starting to come together.

The wooden base was rather thick and so made me wonder about including a drawer. After some machining out the core and then folding a drawer out of brass it is a nifty addition.

The table support shaft and nut were treated with a blacking chemical.


The finished drill with rubber pads under the base and a black front to the drawer.

I looked online for chemical blacking for brass, but did not really want to wait for it to arrive and so just tried the Birchwood Gun Blue that I had bought for the steel components and if applied generously and left then it works rather well.

You do need to clean the parts very well before you apply this bluing chemical and I used Asaka Cleaner.


The only thing that could be better is the drive motor.

I have seen a more powerful sewing machine motor (120W) on ebay that has a white case and rotates in the direction that will allow it to be mounted pointing upwards and so lead to a more compact design.

It would be nice to also make a neat belt cover - something for the future as this is now functional and there are engines to build....


Conclusion

This has been a great project and has resulted in a neat small pillar drill that is just perfect for sensitive drilling with drill bits from 0.5mm to 6mm. The indexing arrangement and 14x1mm thread attachment gives great flexibility.

I think total cost once I buy a new motor will be just under 200.

See also: Tools, Unimat 3 Lathe/Mill.