Boley-Leinen drilling attachment

Edited By NJH on 15/08/2010 18:50:32

Edited By NJH on 15/08/2010 18:52:35

Geoff Here is what I thing you want. The smallest drill chuck was made from a little chuck I bought from as I remember it ‘Expo Drills’. This one had a hole for a tommy bar which is where the fulcrum pin goes in this version. The 7mm was drilled and reamed to take the original chuck stem. Do not forget to cross drill into the bottom of this hole to let the air out and the oil in!

The second largest is made from a Jacobs size ‘00’ I found in the £2 per item at M.E. Exhibition at (I think Ally Pally). They are both for my 6mm Lorch. It has a No 2 MT adaptor for use on the Myford. The big chuck is for drilling square holes.

The 6mm Lorch has a 7mm tailstock so I bought some 7mm silver steel (drill rod)

Edited By Richard Parsons on 20/08/2010 10:19:36

Jupiter! you do ask the 64 megabuck question. I made the thing about 10 years ago and do not really remember the details. If any drawings/sketches were made they would have been in my old workshop notebook now long lost in the move to Hungary.

The length of the bottom bar depends on the length of the stem of the drill chuck. You have to keep enough of the drill chuck stem in the tail stock holder to make certain that chuck is held firmly when it is the full out position. From memory that distance was some 6 to 8mm. The main problem is drilling the hole in the tailstock stem. I am used to drilling deep holes. The barrel for my 1/10^th scale baker rifle was 3.2” long by 1/16” diameter and the 1/5^th scale 0.577 Enfield was well over 6” long by 3mm diameter. The trick is to ‘peck drill’ brushing the drill with a paint brush moistened with cutting fluid after each ‘peck’. About 1 peck in 4 is done just to clear swaff left behind. One easy way to break a drill is to jam it up with swaff. I also use an old fashioned (glass barrelled) syringe with a long vetinary needle to help flush out swaff. The depth of each ‘peck’ should be about the same as the diameter of the drill. The watch word is ‘take it slow and easy’. I reamed the hole and finished it with a ‘tool maker’s broach’.  This is a piece of steel (of the right diameter) whose end is ‘slash cut’ at about 10° hardened and stoned off (there is one in the new pictures). Be careful they are greedy beasts but do not ask them to scrape more than 0.05 to 0.127mm (0.002” to 0.005”. Make certain that the cross drilled hole is made so that it will not get covered up in the tailstock. My Lorch has a slot along its length but I do not know your Boley-Linen at all. Remember the tool you are looking at is for a 6mm lathe yours is an 8mm. The new picture shows the ‘front view’ of the thing. The bottom bar is just pinned with plain pins. Only the bottom bar was reamed and the other holes were drilled a few thou undersized. The two cap screws had points machined in them to fit the ‘Tommy bar’ holes in the chuck

If you ‘right click on at pictures you can then save it to your computer and ‘play tricks’ with your picture editor.

The other large thing in the earlier picture is an adjustable ‘filling rest’ for the Lorch.

Norman it is about the same as mine.  If you can trace the source of the runout you may be able to fix it.  However my Lorch tailstock has some inaccuracies as the bed is of the sliding bar type and i have never measured it's out of line distances. I do not know  the Schubert lathe at all. Mine which is a 'bitza' (I know that parts were made before 1914 and some bits in the late 30's

Edited By Richard Parsons on 28/08/2010 17:13:26

Do you know I cannot remember. I made a sketch and calculated the total movement of the chuck which allowed enough of the chuck stem to remain in the holder. I drew up the bottom bar with its position ½ way along that movement. Drew the centre line of the handle in the forward position and calculated the width of the slot. I marked the centre line of the trunnion holes on the metal at a suitable point (allowing for the length of the lower fork) drilled them tapping size and used that as the centre line of the slot. It is not too critical if everything is marked form the centre of the trunnion holes.

I originally drilled the bottom bar to the calculated length but later I had to revise this as I found the chuck was a little wobbly and needed to be given less travel. I did not bother to shorten the bar hence the extra hole in it.

Hope this helps

Regards

Dick