home  >  Workshop  >  Lab Log 9 February 2020

2019-September - New Top-slide mount for B920 lathe
Everybody complains about the top-slide mount, it just isn't very rigid so I decided to make a Pitkin Donut mount as designed by John Pitkin.
Fortunately I had a bar end of just the right diameter and thickness. The clamps in the photos are made from angle-iron. The 'T' studs are M6 threaded rod welded in 2" long bars which just fit in the T-slots.
The new mount makes a tremendous difference.
Pitkin-Donut Compound Mount for the 9X20 Lathe.pdf
Pitkin-Donut Compound Mount Machining Instructions.pdf

2019-May - Saddle-clamp for B920 lathe
The saddle can be clamped using an Allen key in a bolt in the saddle. The key was always somewhere else or fell out so I made a new clamp. I turned a piece of 12mm bar and threaded one end M6. The handle has to be removable to get the clamp screw in and out of the hole. I screwed the new clamp in by hand and marked where the handle hole should be, drilled and tapped a hole M6 and made the hande with a slot at the end so it can be tightened in (and removed) using a screwdriver.
Yes the photo shows the Pitkin Donut, I didn't take the photo when I made the clamp.

2019-04-08 - New Cross-slide handle for B920 lathe
Ever since I got the lathe I have found the throw on the cross-slide handle was too small. I decide to improve it and rough sawed a piece of 3/8" aluminium plate to just over 80mm diameter, put it in the 3-jaw and faced it and drilled and bored a centre hole about 47mm, just smaller than the cross-slide handle disc. Gripped it by the centre bore and faced the other side then turned the diameter to 80mm. Holding it by the outer edge I bored it so it would just slide over the original disc, drilled and tapped a hole to take the original handle and fastened it in place on the original disc using threadlock. When the threadlock had set I moved over the handle. Now with the larger throw I have so much more control of the feed.

2017-03-14 - Flexible Drive coupling
A friend bought a flexible drive and second hand sewing-machine motor and needed them connecting. The drive had an 8mm shaft and the motor a 1/4" spindle cross drilled and tapped near M3. The thread was a very good fit for an M3 screw but it would only go 3/4 of the way through from either side - goodness knows what the thread really was so I ran an M3 tap right through. I made the coupling from 30mm of 3/4" bar, faced off in the lathe and bored 8mm dia. x 20mm at one end for the flexible drive and 1/4" dia. x 10mm at the other. Four M6x6mm set screws at 90deg hold the 8mm shaft in place and a recessed M3 screw fastens the motor shaft.

2016-11-19 - BL-920 four-jaw chuck
While making muscle ends for the Shadow-Leg-Mk2 I used the four-jaw chuck supplied with the lathe and the best description for it is 'agricultural'. Twenty years ago Patrick had givn me a 6" four-jaw intended for a previous lathe but I couldn't get a backplate for that lathe. I eventually found that Chester Machine Tools sold a backplate for the BL-920 and ordered one but it didn't fit - the nose register was too small a diameter! Non of their other stock fitted their 920s either - hmm. So I scraped the backplate register to fit the lathe nose register, turned it to fit the recess in Patrick's chuck, cleaned off all the surface rust from the chuck and fitted it. Fantastic.

2016-11-17 - BL-020 lathe back-gear problems
Of course repairing the bearing wasn't the only problem. I have always used the back-gear because it was almost impossible to get the V-belt onto the motor and spindle pullies, it was dangerously tight. How the belt arrangement was originally set up I don't know but accountants/time-and-motion-people seemed have been involved in a re-design. The first step was to position the motor so the V-belt could be slipped onto the motor and spindle pullies and then tensioned using the tensioning arm. Of course with the motor in the right position the back-gear mounting plate, which is held in position by two screws by the spindle, had to be at a crazy angle for the back-gear toothed belt to fit on the pullies, which meant the gear cover didn't fit properly and it all looked like a train wreck. So I adjusted the back-gear plate nice and square with the lathe and determined that the back-gear stud needed to be about 1/2" higher so the toothed belt was at proper tension. I filed a slot in the back-gear plate so the stud was in the proper place and the tension could be adjusted. That done the belts can be repositioned and changed and the guard door fits.

2016-11-17 - BL-020 lathe back-gear bearing problems
Continued from 2016-10-27
The Oilite bearings arived, so I polished the Back-gear stud, turned out the old phosphor-bronze bearings and turned recesses in the back-gear hub to take the new Oilite bearings. Polishing the stud left it a little undersize but it will be a lot better than it was and I bought six Oilite bearings so have four spare if I need to replace them in the future.

2016-11-07 - Black and Decker Jobber
While making a window box I used my Black and Decker Jobber on my new outside workshop table, however it was difficult to hold the wood because it really needed four more holes for the dogs, one at each corner. In addition one of the plastic handles was quite tight on the aluminium so I took the Jobber apart, cleaned up the handles and used a Forstner bit to drill four new holes.

2016-11-06 - Pillar-drill depth-stop
The depth-stop-lock on my pillar-drill has always been difficult to use - it is too short. I got another handle in a box of bits from a friend and swapped them over. Now adjusting the depth-stop is easy.

2016-11-06 - Bandsaw table
The area of my bandsaw table round the blade had worn and remembering a bandsaw project on California Gears I cut a square out of the table and made a drop-in piece.

2016-11-03 - Workshop table
For some time I had been considering where I could fit an outside table for dusty/dirty work then I realised I could make one that folded up. I bought two treated "gravel-boards" and three sturdy hinges, sanded the gravel-boards and used an offcut of a treated 3" fence post as the wall mount fixed to the wall with two frame-screws. I was going to fit a spike to the drop-down leg which would go into the lawn to stop the bottom of the leg moving but it turned out not to be necessary and the table is very rigid. A simple wooden swivel lever holds it in the up position.

2016-10-27 - BL-020 lathe back-gear bearing problems
The Back-gear bearing started to make noises and when I stripped it down it was obvious why. The oil had not been getting to where it ought to have gone because the oilway was gummed up. However that was only part of the problem, the back-gear stud seemed to have only been rough turned and not polished, consequently the phosphor bronze bearings were quite worn. What to do? I could turn new bearings from Phosphor bronze bar but decided to get some Oilite bearings instead. Continued on 2016-11-17
I wasn't the only one - "When my ~ 10yr old 9x20 was new, the shafts for the "a" gear and idler gear were bent; while the surface finish on the clutch pulley shaft was rough and it quickly ate up the brass clutch pulley bushings. All fixable, but still a nuisance. Bill" 9x20Lathe@yahoogroups.com 2018-01-19

2014-03-17 - Angle Grinder Attachment for Lathe
I needed to cut some rings from a steel tube for muscle ends. Last time I did that I chucked lengths of tube in the lathe and held an angle grinder by hand. It worked well but I did loose a couple of rings as the cutting disk skidded over the tube and marked it. This time I decided to try out a holder for an angle grinder which turns it into a chop saw, I bought it last year from Lidl for about 15. I was surprised when I assembled it, it was actually very good. My friend Jim Whiting made an attachment to hold an angle grinder on the cross-slide of his lathe and I had thought about making one then I wondered could the Aldi one be adapted? It turned out it was so simple.

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