Unimat SL Adjustable Drill Stop

**Paul Jones** · Sep 26, 2015, 03:12 PM

I want to share some photos of an improvement I made to my Unimat SL 1000 lathe which has a 3" swing. I bought this lathe new in 1970, used it for a few years and then put into storage. I now use the Unimat for machining parts too small for my 7” and 12” lathes.

One of my Unimat improvements was permanently installing a milling and drilling head (see Homemade Lathe Modifications ). The milling and drilling head depth of cut can be adjusted with both a lead screw for milling and a spindle feed lever for drilling. I added an adjustable drill stop and digital dial indicator for repetitive drilling operations. There is a knurled collar used to set the depth and collar and stop rod can be lowered and then returned to its previous stopping depth when needed. An additional benefit the adjustable drill stop can hold a dial test indicator when the spindle is in use.

**DIYer** · Sep 27, 2015, 09:48 PM

Thanks Paul Jones! We've added your Unimat SL Adjustable Drill Stop to our Machining category, as well as to your builder page: Paul Jones's Homemade Tools. Your receipt:

Unimat SL Adjustable Drill Stop by Paul Jones

tags: drill, adjustable, stop

**PJs** · Sep 29, 2015, 11:29 AM

Paul you have really put together quite a machining center with all the goodies you added and made for it. I particularly like the indexing wheels you've added to both...the ops seem endless with that combo. Also the hand wheel Z axis is a Nice touch. How much throw does that have? Being able to attach a DTI to your knurled depth stop for setup is quite brilliant.

Thanks for sharing these great projects with us...my mind is reeling with ideas to mount a similar milling system to my meager mini now! It's funny because I recently did some poor man milling on my mini recently and was thrilled to be able to do it. Thanks Much! ~PJ

**Paul Jones** · Sep 29, 2015, 02:23 PM

PJs, thank you for the feedback. I had fun designing the modifications, but my recommendation for a milling/drilling head addition is not to use a Unimat headstock assembly. I used it because I had a spare Unimat headstock but it has its limitations. The maximum of spindle movement is approximately 0.62" , the 25mm diameter milling head column should be larger and rectangular (loss of registration when moved up or down but I have a solution and will post it), and the spindle thru hole is too small. I learned to work around these limitations and the machine can produce excellent small parts. The smaller the machine, the longer the set up time. I think next time I would adapt something more like the homemade drilling attachment ( Taig Mill ) built by John R. Bentley. He does beautiful engineering and machining for his engines and his tools. You should check out his website.

Thank you, Paul Jones

**PJs** · Sep 29, 2015, 02:57 PM

Most welcome Paul and bet you did have some fun with all of that...looks beautiful. I hear you about the Unimat head but your build reminded me my neighbor (saves all kind of goodies for me) had a nice looking baby DP a week or so ago with about a 2" column and probably a 2" throw. No idea how good the spindle or bearings are but those are fixable and might offset the head on the column to cobble something together. I got an old (1986) 6" large frame grinder from him for free a while back that was dropped and left in a puddle and it turned out great and now my primary grinder, not a buffer anymore. Cost me $17 in bearings and new cord and of course about 20hrs of cleanup/paint. This might be another really useful project to putz with!