Member postings for Adrian Dixon

As stated above my understanding was to open existing holes (note ref. to casting 'cored hole' ). They reputedly give a more accurate and better finished hole than a standard drill and are a half way house to a reamer, but definately no substitute for one. I have, I think, one in the workshop and have never used it!

Adrian

(Contd. from previous posting - text was too long for one!)

I was lazy when it came to the thread indicator attachment stud and did not make the bolt come stud as per drawing but used a length of commercial ¼” BSF studding I had in stock with the original nut to secure the indicator. Then came the next problem, the stud did not line up with the tapped hole in the 3/8” bar, this despite careful marking for the hole in the block as recommended in the instructions. The cause soon became apparent and was no reflection on my machining nor the design. Without the thread indicator fitted all was perfect, the faces on the indicator were not square to the bore nor parallel to each other, hence when the nut was tightened the stud deflected off centre! To be fair to Myford we are trying to do something that was never intended, hence this out of square was previously of no importance. I turned up a stub in the chuck that was a push fit in the bolt hole in the indicator and skimmed the faces true and all was well.

The final word of warning…..all then fitted and worked well but if you have a power cross-feed machine be aware that the inner end of the shaft that carries the push – pull knob for engaging and disengaging the feed can foul the T bar at the inner end of travel with possibly severe consequences. There is ‘free’ movement at the inner end of the travel of the shaft after the drive is disengaged so I removed the knob and both circlips (one in front and one behind the knob) and fitted a 1/16” thick washer behind the second circlip which prevents the shaft travelling far enough in to foul the T strip. Another option may be to chamfer the ends of the T on the front face so the shaft will ride out and thus not cause a jam up. Your choice.

I’m sorry if this is long winded, but it is all fairly simple really and may help someone in the future. At the end of the day we are trying to shoe horn stuff into places that was never intended, hence maybe only fair to expect some issues?

Regards,

Adrian

In the absence of any further responses and now having completed the saddle stop I am able to offer the following information that may benefit others in the future(?). This applies to the installation for my long bed Super 7 with power cross-feed of 1980 vintage and may differ for other machines……….certainly my earlier pre power x-feed machine does vary slightly. There is very limited clearance for the saddle / apron assembly to pass with the T strip fitted due to the proximity of the saddle plate above, the rack pinion shaft below and the apron to the front. Before starting it is necessary to remove the cast alloy leadscrew guard and the blackened sheet steel piece behind it as these will foul the T strip. Once the T strip is fitted the sheet item can be reduced by about 1/16” on its inner edge to clear and a small corner (maybe 1/8” x 1/8” ) cut from the bolting flange of the guard. This does mean the assertion that ‘no modification to your lathe is necessary’ is not strictly true!

The T strip that attaches over the rack was machined from 5 x 12mm BMS strip in lieu of the supplied ¼ x ½” and the width was reduced from the stated 0.455” to approx 0.430”.

The 3/8” was maintained but the 1/8” thicknesses were reduced to approx 2.5mm each – although I erred on making the thickness of the top of the T slightly under and preferring to leave a shade more meat on the lips on the cast iron block.

The holes for securing to the lathe were offset towards the top edge of the strip, thus lowering the strip, by drilling about 12 thou off centre – without this the strip fouled the plate that holds the saddle down on the lathe bed. Note that due to the reduced thickness of the strip you cannot use 2BA cap screws as there is no room for metal under the head! My solution was to countersink and substitute 2BA x ¾” long socket head countersunk screws. As my machine is a long bed I made the T strip about 14” long and span 5 rack screws rather than 3 as per drawing – but note that the pitch of the screws is 3.300” on my machines – not 3.5” as stated on the drawing, though to be fair they do state to use the rack as a drill jig. I didn’t, just relying on the feed screws on my D/W for spacing and all was ok.

The position of the hole, in the CI block, for the brass clamp pads for the tee needs to be relative to the ‘T slot’ not the edge of the block.

The suggested woodruff cutter was no longer suitable due to the size changes and I opted to make my own cutter from 5/16” dia silver steel with a slot across the end and a small scrap of carbide brazed in and ground up – looks a bit like a boring tool. For security I threaded the holding end and used in the autolock chuck and basically flycut the undercuts one side at a time.

Edited By Adrian Dixon on 11/01/2012 21:11:36

Edited By Adrian Dixon on 11/01/2012 21:11:59