THE GEAR TRAIN FOR THE SLOW FEED AND SCREWCUTTING
NOW THAT THE CLUTCH PROBLEM WAS SOLVED THE GEAR TRAIN HAD TO BE PUT IN PLACE. THE ORIGINAL SCREWCUTTING GEAR TRAIN ON THE EW WAS NOT ABLE TO GIVE THE LOW GEAR RATIO THAT WAS NEEDED FOR THE SLOW FEED. ALSO, THE WAY THAT SCREWCUTTING WAS CARRIED OUT, WAS TO FIT A CRANKING HANDLE TO THE INPUT PULLEY OF THE COUNTERSHAFT AND TURN THE LATHE SPINDLE MANUALLY. THIS WORKED BUT NOW WITH THE LEADSCREW CLUTCH IN PLACE, SCREWCUTTING COULD BE DONE THE NORMAL WAY UNDER POWER.
THE SLOW SPEED GEAR TRAIN WAS A PROBLEM AND MARTIN CLEEVE SOLVED THIS BY MAKING AN EXTERNAL GEARBOX THAT CERTAINLY LOOKED LIKE THE INTERNALS OF A GRANDFATHER CLOCK. YOU CAN SEE THIS IN THE MODEL ENGINEER COVER PHOTO AS SHOWN ABOVE.
WITH A BIT OF LATERAL THINKING I WAS ABLE TO SOLVE THE PROBLEM SIMPLY WITHOUT ALL THAT CLOCK NONSENSE
THE SLOW SPEED GEAR TRAIN WAS A PROBLEM AND MARTIN CLEEVE SOLVED THIS BY MAKING AN EXTERNAL GEARBOX THAT CERTAINLY LOOKED LIKE THE INTERNALS OF A GRANDFATHER CLOCK. YOU CAN SEE THIS IN THE MODEL ENGINEER COVER PHOTO AS SHOWN ABOVE.
WITH A BIT OF LATERAL THINKING I WAS ABLE TO SOLVE THE PROBLEM SIMPLY WITHOUT ALL THAT CLOCK NONSENSE
ABOVE ARE PHOTOS OF THE ORIGINAL EW SCREWCUTTING BANJO ASSEMBLY. VERY SIMPLE AND ADEQUATE FOR THE ORIGINAL DESIGN. HOWEVER I WANTED TO HAVE POWER SLOW FEED AND SIMPLE WITH IT.
ABOVE IS MY ORIGINAL DESIGN SKETCH FOR THE SCREWCUTTING / SLOW FEED BANJO. PLEASE NOTE: THAT DUE TO THE SPACER USED UNDER THE ORIGINAL BANJO I WAS ABLE TO DESIGN A SPLIT ARTICULATING BANJO THAT WOULD ALLOW ENOUGH COMPOUND GEARS TO GIVE THE FINAL RATIO REQUIRED AND HAVE THE LEADSCREW TURN IN THE CORRECT ROTATION. INSTEAD OF USING 16DP GEARS AS ON THE ORIGINAL EW, I USED 20DP GEARS AS USED ON THE MYFORD LATHE. THE REASON BEING THAT THE GEARS WERE EASILY OBTAINABLE SECONDHAND AND CHEAP, AS WELL AS MAKING A MORE COMPACT ASSEMBLY. THE GEAR SPINDLES ARE MODIFIED MYFORD ONES.
I HAVEN`T FULLY EXPLORED THE EXTENT OF THE POSSIBLE LOW RATIOS BUT WITHOUT RE CALCULATING THE ACTUAL RATIO AT PRESENT ON MY EW, I BELIEVE THIS TO BE AROUND 160 TPI OR MORE.
I HAVEN`T FULLY EXPLORED THE EXTENT OF THE POSSIBLE LOW RATIOS BUT WITHOUT RE CALCULATING THE ACTUAL RATIO AT PRESENT ON MY EW, I BELIEVE THIS TO BE AROUND 160 TPI OR MORE.
ABOVE THE UPDATED DRAWING FOR THE SPLIT ARTICULATING BANJO PLEASE NOTE THAT THE DRAWING IS FOR LASER CUTTING OF THE PARTS WITHIN THE CUTTING TOLERANCES OF THE MACHINE SO THAT THE DIAMETERS FOR THE LEADSCREW AND THE WIDTH OF THE SLOTS ARE NOT THE NOMINAL SIZES. THIS IS A PROTOTYPE SO THAT I DID`NT INCLUDE A LOT OF RADII TO MAKE IT EASIER ON THE EYE.
THE ABOVE PHOTOS SHOW THE PROTOTYPE BANJO CUT OUT AND THEN ASSEMBLED ON THE LATHE
THE ABOVE PHOTOS SHOW THE GEAR TRAIN IN SITU AND I MUST SAY THAT I`M HAPPY WITH THE RESULT AND CAN TAKE 1/16" CUTS (1.5mm) WITH LOVELY CONTINUOUS SWARF ALL DAY, THE LIMITING FACTOR IS BELT SLIP.
THESE MODIFICATIONS HAVE MADE THE LATHE MUCH MORE PLEASANT TO USE!
THESE MODIFICATIONS HAVE MADE THE LATHE MUCH MORE PLEASANT TO USE!
EW SCREWCUTTING USING THE ORIGINAL EW GEARS
IT SUDDENLY STRUCK ME THAT THERE MAY BE EW OWNERS THAT HAVE COMPLETE SETS OF ORIGINAL GEARS SO THAT THERE WOULD BE NO NEED TO BUY IN MYFORD GEARS FOR THE GEAR TRAIN IF THAT IS THE CASE.
ABOVE A COPY OF THE ORIGINAL EW SCREWCUTTING CHART KINDLY SUPPLIED BY NORMAN.. THESE ARE THE THREADS AVAILABLE USING THE ORIGINAL EW SCREWCUTTING KIT.
EW SLOW FEED AND SCREWCUTTING USING THE ORIGINAL EW GEARS WITH SPLIT BANJO.
ABOVE LEFT THE "ROTRING" A4 PLASTIC TABLE TOP DRAWING BOARD THAT I USE TO SKETCH OUT THE DESIGNS THAT APPEAR ON THESE PAGES. I DO HAVE A FULL SIZE DRAWING BOARD IN THE WORKSHOP BUT IT`S NICE TO SIT AT HOME IN THE WARM WHEN DRAWING. ON THE RIGHT I`VE SKETCHED IN THE HEADSTOCK END OF THE EW IN ORDER TO FIND THE GEAR RATIOS THAT CAN BE ACHIEVED USING THE TEN GEARS THAT COMPRISE THE ORIGINAL SET.
YOU WILL NEED TO MAKE THE SPLIT BANJO SHOWN ABOVE TO UTILISE THE PROPOSED GEAR TRAINS
YOU WILL NEED TO MAKE THE SPLIT BANJO SHOWN ABOVE TO UTILISE THE PROPOSED GEAR TRAINS
GEAR TRAIN WITH TWO COMPOUND GEARS
THE TWO IMAGES ABOVE SHOW THE EASY WAY TO FIGURE OUT THE RATIOS WITHOUT ALL THE ASSEMBLING AND DIS ASSEMBLING OF THE GEARS ON THE BANJO. WHAT I DID WAS TO DRAW THE HEADSTOCK END OF THE LATHE FULL SIZE AND PLACING PLASTIC FILM OVER THIS, WAS ABLE TO LAY OUT THE GEARS ON THE SKETCH TO PROVE THE RATIOS THAT COULD BE ATTAINED.
THIS TRAIN USES THREE 65 T GEARS (C,E & G), TWO 20 T GEARS (A & F), B IS 35 T & D IS 25 T.
THIS GIVES A TPI OF 220. I USED THE DUPLICATE GEARS THAT I HAVE TO ACHIEVE THIS RESULT AND THE NEXT TRAIN WILL BE BASED ON ONLY THE TEN AVAILABLE GEARS IN THE SET.
THIS TRAIN USES THREE 65 T GEARS (C,E & G), TWO 20 T GEARS (A & F), B IS 35 T & D IS 25 T.
THIS GIVES A TPI OF 220. I USED THE DUPLICATE GEARS THAT I HAVE TO ACHIEVE THIS RESULT AND THE NEXT TRAIN WILL BE BASED ON ONLY THE TEN AVAILABLE GEARS IN THE SET.
ABOVE THE SLOW FEED GEAR TRAIN USING ONLY GEARS FROM THE ORIGINAL SET OF TEN THIS GIVES A SLOW FEED OF 114 TPI WHICH ISN`T QUITE ENOUGH. A NORMAL SLOW FEED WOULD BE AROUND 180 TPI.
IF WE REPLACE THE 30T GEAR (D) BY THE DRIVER 25T GEAR AT (F) AND USE A NEW 20T GEAR AT (F) THEN THE FEED WILL BE 172 TPI WHICH WOULD BE A GOOD SOLUTION FOR US.
I BELIEVE THAT MOST EW USERS SELDOM DO SCREWCUTTING AND WOULD JUST LIKE THE SLOW FEED TO BE CONTINUOSLY AVAILABLE AND LIKE MYSELF, USE TAPS AND DIES TO CUT THE SMALLER THREADS THAT WE USE.
IF WE REPLACE THE 30T GEAR (D) BY THE DRIVER 25T GEAR AT (F) AND USE A NEW 20T GEAR AT (F) THEN THE FEED WILL BE 172 TPI WHICH WOULD BE A GOOD SOLUTION FOR US.
I BELIEVE THAT MOST EW USERS SELDOM DO SCREWCUTTING AND WOULD JUST LIKE THE SLOW FEED TO BE CONTINUOSLY AVAILABLE AND LIKE MYSELF, USE TAPS AND DIES TO CUT THE SMALLER THREADS THAT WE USE.
ABOVE, PAGES FROM THE CURRENT HPC ONLINE CATALOGUE. FOR THOSE THAT HAVE NOT SEEN THEIR PRODUCTS BEFORE, THEY SUPPLY ALL KINDS OF INTERESTING SMALL PARTS THAT INCLUDE LEADSCREWS THAT CAN BE FITTED TO THE EW WITH A LITTLE MODIFICATION.
THE 20T GEAR ONLY COSTS 16 GBP BUT WILL HAVE TO BE BORED OUT TO 5/8" AND THINNED DOWN TO 5/16 THICK.
THE 1/16" DIA HOLE FOR THE DRIVE PIN CAN BE DRILLED BY SIMPLY DRILLING THROUGH THE EXISTING HOLE IN THE DRIVE COLLAR (ALL THE COLLARS THAT ARE USED ON THE EW ARE DRILLED FOR THE DRIVE PIN), THIS CAN THEN BE USED AS A DRILLING JIG FOR ANY NEW GEAR THAT YOU MAY WANT TO FIT, INCLUDING THE MYFORDS.
THE 20T GEAR ONLY COSTS 16 GBP BUT WILL HAVE TO BE BORED OUT TO 5/8" AND THINNED DOWN TO 5/16 THICK.
THE 1/16" DIA HOLE FOR THE DRIVE PIN CAN BE DRILLED BY SIMPLY DRILLING THROUGH THE EXISTING HOLE IN THE DRIVE COLLAR (ALL THE COLLARS THAT ARE USED ON THE EW ARE DRILLED FOR THE DRIVE PIN), THIS CAN THEN BE USED AS A DRILLING JIG FOR ANY NEW GEAR THAT YOU MAY WANT TO FIT, INCLUDING THE MYFORDS.
GEAR TRAIN WITH THREE COMPOUND GEARS
USING ONLY THE ORIGINAL GEARS, I EXPERIMENTED WITH HAVING A THIRD COMPOUND GEAR BUT THIS TRAIN ONLY PRODUCED 204 TPI. THIS COULD BE IMPROVED BY MODIFYING THE LOWER PART OF THE SPLIT BANJO.
I WON`T ELABORATE ON THIS THEME AS WE CAN ALREADY GET SATISFACTORY FEEDS WITH THE TWO COMPOUND GEAR TRAIN AS SHOWN ABOVE.
I WON`T ELABORATE ON THIS THEME AS WE CAN ALREADY GET SATISFACTORY FEEDS WITH THE TWO COMPOUND GEAR TRAIN AS SHOWN ABOVE.
SLOW FEEDS USING MYFORD GEARS.
ABOVE LEFT, YOU CAN SEE THE PROBLEM IN USING THE MYFORD GEARS. THEY ARE 3/8" THICK WHEREAS THE EW GEARS ARE 5/16" THICK! YOU WILL HAVE TO MAKE A SPACER TO FIT BETWEEN THE SPINDLE GEAR AND THE ADJUSTING NUT TO BRING THE GEARS INTO LINE. THE MINIMUM GEAR SIZE THAT WILL FIT ON THE SPINDLE IS 25T AND YOU WILL HAVE TO SKIM A FEW THOU OFF THE OD OF THE EW DRIVING COLLAR TO ALLOW THE GEARS TO MESH PROPERLY. THIS WON`T AFFECT IT`S FUNCTION WHEN USED WITH EW GEARS.
I THINK THAT THE 20T GEAR COULD BE MADE TO FIT ON THE SPINDLE AND WILL LOOKINTO THIS SOON.
ABOVE RIGHT IS SHOWN AN EW 65T GEAR WITH A MYFORD 65T ON TOP OF IT. THE MYFORD GEARS MAKE A MUCH MORE COMPACT GEAR TRAIN ASSEMBLY AND IF YOU DON`T HAVE EW GEARS THEN THIS IF THE WAY FORWARD. USING THE SPLIT BANJO THE MYFORD GEARS ADAPT PRFECTLY ONTO THE EW. BUT YOU WILL NEED THE EW GEARCUTTING BACKPLATE FITTED TO ENABLE THIS.
ALSO REQUIRED ARE THREE MYFORD GEAR HOLDERS THAT WILL HAVE TO BE MODIFIED TO FIT THE BANJO. THIS CAN BE DONE BY CAREFUL FILING OR ON THE LATHE OR MILLING MACHINE. BE AWARE THAT THERE HAVE BEEN PROBLEMS WITH THESE HOLDERS SUPPLIED BY CERTAIN SUPPLIERS CAUSED BY THE CHINESE MADE EXAMPLES BEING POORLY MADE. THESE SUPPLIERS DO NOT CHECK THE COMPONENTS ON DELIVERY AND IF ONE COMPLAINS, JUST SAY SEND THEM BACK AND WE WILL SEND NEW ONES, NOT A SATISFACTORY STATE OF AFFAIRS!
I THINK THAT THE 20T GEAR COULD BE MADE TO FIT ON THE SPINDLE AND WILL LOOKINTO THIS SOON.
ABOVE RIGHT IS SHOWN AN EW 65T GEAR WITH A MYFORD 65T ON TOP OF IT. THE MYFORD GEARS MAKE A MUCH MORE COMPACT GEAR TRAIN ASSEMBLY AND IF YOU DON`T HAVE EW GEARS THEN THIS IF THE WAY FORWARD. USING THE SPLIT BANJO THE MYFORD GEARS ADAPT PRFECTLY ONTO THE EW. BUT YOU WILL NEED THE EW GEARCUTTING BACKPLATE FITTED TO ENABLE THIS.
ALSO REQUIRED ARE THREE MYFORD GEAR HOLDERS THAT WILL HAVE TO BE MODIFIED TO FIT THE BANJO. THIS CAN BE DONE BY CAREFUL FILING OR ON THE LATHE OR MILLING MACHINE. BE AWARE THAT THERE HAVE BEEN PROBLEMS WITH THESE HOLDERS SUPPLIED BY CERTAIN SUPPLIERS CAUSED BY THE CHINESE MADE EXAMPLES BEING POORLY MADE. THESE SUPPLIERS DO NOT CHECK THE COMPONENTS ON DELIVERY AND IF ONE COMPLAINS, JUST SAY SEND THEM BACK AND WE WILL SEND NEW ONES, NOT A SATISFACTORY STATE OF AFFAIRS!
I FITTED THIS TRAIN OF MYFORD GEARS TO THE EW AND IT RAN AS QUIETLY AS IT SHOULD. IT`S BASICALLY THE SAME CONFIGURATION AS FOR THE EW TWO COMPOUND GEAR TRAIN ABOVE, USING THE SAME IDENTIFICATION, GEAR A IS 25T GEAR B 40T GEAR C 70T GEAR D 30T GEAR E 75T GEAR F 20T & GEAR G 95T. THIS GIVES A FEED OF 266 TPI. THIS IS TOO SLOW, WE WOULD BE NODDING OFF WHILE THE CUTS WERE TAKING PLACE BUT IT`S ONLY AN EXAMPLE AND I WILL GET IT DOWN TO AROUND 180 TPI NO PROBLEM.
MODIFYING THE MYFORD GEAR HOLDERS TO SUIT THE EW
ABOVE THE CHINESE VERSION OF THE GEAR HOLDER PIVOTS AND AN EXPLODED VIEW
ABOVE LEFT, THE MODIFICATIONS THAT NEED TO BE CARRIED OUT TO THE PIN.
ABOVE RIGHT, THE PROBLEM WITH THE ASSEMBLY IS NOT THE CARRIER FOR THE GEAR WHICH IS SATISFACTORY BUT THIS BUSH WHICH IN MOST CASES WERE UNDERSIZED BY AROUND .020" WHICH CAUSED THE GEAR CARRIER TO WOBBLE ALARMINGLY. I MENTIONED THIS FACT ON THE MODEL ENGINEER FORUM WHICH LED TO AN AMAZING RESPONSE FROM "SATISFIED" CUSTOMERS OF THE VENDOR RESPONDING THAT TWENTY THOU UNDERSIZE WAS OK AND WHAT WAS I COMPLAINING ABOUT! THE VENDOR ALSO RESPONDED IN THE SAME LIGHT, SAYING THAT THEIR "ENGINEER" CONSIDERED THAT THIS UNDERSIZE WAS SATISFACTORY BUT MOST OF THE REPLACEMENTS THAT HE SENT ME HAD THE SAME PROBLEM.
ANY EXPERIENCED ENGINEER, WITHOUT EVEN HAVING TO LOOK AT THE "NEWALL FITS SYSTEM", WOULD CONSIDER FOR THE ACTUAL USE OF THE BUSH THAT A TOLERANCE OF - .001 -.0015 WOULD BE AROUND THE CORRECT FIGURES.
THE BEST THING TO DO IF ONE RECEIVES SUCH RUBBISH IS TO MACHINE UP A NEW SET OF BUSHES, BETTER THAN WASTING YOUR TIME COMPLAINING AND THROWING AWAY PRECIOUS MONEY SENDING THEM BACK TO THE VENDOR JUST TO RECIEVE BACK THE SAME PROBLEMS THAT YOU COMPLAINED ABOUT.
ABOVE RIGHT, THE PROBLEM WITH THE ASSEMBLY IS NOT THE CARRIER FOR THE GEAR WHICH IS SATISFACTORY BUT THIS BUSH WHICH IN MOST CASES WERE UNDERSIZED BY AROUND .020" WHICH CAUSED THE GEAR CARRIER TO WOBBLE ALARMINGLY. I MENTIONED THIS FACT ON THE MODEL ENGINEER FORUM WHICH LED TO AN AMAZING RESPONSE FROM "SATISFIED" CUSTOMERS OF THE VENDOR RESPONDING THAT TWENTY THOU UNDERSIZE WAS OK AND WHAT WAS I COMPLAINING ABOUT! THE VENDOR ALSO RESPONDED IN THE SAME LIGHT, SAYING THAT THEIR "ENGINEER" CONSIDERED THAT THIS UNDERSIZE WAS SATISFACTORY BUT MOST OF THE REPLACEMENTS THAT HE SENT ME HAD THE SAME PROBLEM.
ANY EXPERIENCED ENGINEER, WITHOUT EVEN HAVING TO LOOK AT THE "NEWALL FITS SYSTEM", WOULD CONSIDER FOR THE ACTUAL USE OF THE BUSH THAT A TOLERANCE OF - .001 -.0015 WOULD BE AROUND THE CORRECT FIGURES.
THE BEST THING TO DO IF ONE RECEIVES SUCH RUBBISH IS TO MACHINE UP A NEW SET OF BUSHES, BETTER THAN WASTING YOUR TIME COMPLAINING AND THROWING AWAY PRECIOUS MONEY SENDING THEM BACK TO THE VENDOR JUST TO RECIEVE BACK THE SAME PROBLEMS THAT YOU COMPLAINED ABOUT.
IN PROGRESS