Thursday, January 13, 2011

Monty Remon's Taig Lathe Mods, Part 1

“First, the drilling tailstock. I got rid of the hex head clamping bolts like every one else and elected to replace them with ratcheting levers fitted with brass washers, they can now be aligned for ergonomic or aesthetic reasons. Note the length of 1/8"x1/2" brass angle under the ram clamping lever to spread the load over 3 /4". Next job to be attacked was that little lever which has caused so much pain after a heavy drilling session. I decided not to go down the 'mine is bigger than yours road' and attach a 12" billet of titanium so that it dug me in the ribs as I walked passed, and instead this telescopic assembly sort of evolved. It is 1/2"x1/2" alloy bar fitted with a ss draw knob at the end for comfort and a spring and ball bearing catch let in near the other end. The original arm is replaced by a length of 5/8" x 18g box section steel with a short length of 1/8" bar silver soldered on the side and holes drilled to accept the ram and link pin fixings(*). The underside has holes drilled at 1" spacing to allow the lever to step out to any length required, 9" is enough to hang your hat on.
(*)It is too easy to copy the pivot spacing dimensions of the original lever but they are not the best! Set up your lever assy., to mid., travel and you will most likely see lots of 90 deg. angles. Now if you are like me and you do lots of full stroke drilling then any deviation either side of the ram mid position causes the link to deviate from parallel and increases the ram side loading (on 1/8" air gap!) If the hole spacing on the lever is made 1/16" greater than the ram c/l to link pivot dim., then the side loads are decreased because the link swings through an arc and is aligned twice, and therefore decreased side loads.”


“The next addition was stimulated by pictures from other web site donors who rotated the tailstock assy., 180 deg. to get the drill chuck nearer (3/4") to the work piece (the 't' slots were used to retain a bar for dropping a mounting for the link /pin). My scrap box came up with a different solution. Two links and a triangular mounting plate (should be brass). The plate thickness must be such that it is a loose fit in the existing clamping slot when the drilling ram is locked, the plate is located by the slot, the clamping bolt and the sliding ram (that's the reason for the brass). New pins were made for the pivots to take slack out the system. A quickly reversible job. (A sort of pun)”remon08remon07

“The next job of making the ram wind in and out with accuracy eluded me for ages. I had a system on the drawing board that used the end of my telescopic arm to engage in an acme type thread for quick disconnect but it would not give linear micrometer type accuracy - back burner for a while. The solution was found by accident! One day I had in my possession a used drilling tailstock and I noticed a hole drilled and tapped 1/4"x20 set below the ram? I had no idea of its original purpose so I fitted the assembly to a lathe bed and screwed a length of 1/4 x20 rod in place, I stared at this setup in a menacing manner for the duration of a cup of coffee. A visit to the scrap box yielded a short length of 1/2" diam.,brass bar, this was drilled and tapped 1/4x20 for 1" length and the rest was 1/4" to clear the thread. A 1/8" external groove at the threaded end to finish, this was then screwed home and a long split pin dropped through the ram end into the groove. I found it possible to drill 1/4" holes by rolling the rod between thumb and finger! I allowed myself a ten minute smug break then substituted DELRIN for the brass rod and a temp., knob/spinner fitted, there is no slack in the groove/thread department. The threaded rod is now fitted to a piece of 1/2x1/2 alloy bolted under the tailstock so that things line up with my telescopic lever assy., this system will permit changing to a stiffer 3/8 rod if needed. The ram pin features a knob with saddle seating at two depths and 90 deg. apart, a 1/4 turn on this allows instant switching between systems at any stroke position. YI - HA. A new free index able graduated winding knob is on the cards, it involves acrylic, antifreeze, printer ink and an 'O' ring! If it works I feel a smug level '10' coming on.”


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