THE DIAL GAUGE (EXTENSION) BEARS ON THE TOP OF THE DRAWBAR WHICH HAS BEEN MACHINED FLAT.
This attachment consists of 6 main parts.
1. SOCKET MOUNTING BRACKET
2. SHAFT MOUNTING SOCKET.
3. SHAFT
4. ADJUSTER BLOCK ASSEMBLY
5. INDICATOR HOLDER/ADJUSTER ASSEMBLY
6. AND, OF COURSE, THE DIAL GAUGE.
1.
SOCKET MOUNTING BRACKET
MATERIAL: ALUMINUM ANGLE - 2 X2 X 1/4" X 3"
MARK OUT AND DRILL THREE EQUALLY SPACED #7 HOLES ON ONE SIDE OF THE ANGLE 1" FROM THE OUTSIDE EDGE.
2.
THE SHAFT MOUNTING SOCKET***********************************insert photo when available - link drawing when available**************
MATERIAL: 2 1/2 OR 3 INCH BRASS SHAFTING X 3 INCHES LONG.
CHUCK IN LATHE, FACE OFF, AND DRILL A 3/8" HOLE (CENTERED) ABOUT 2"DEEP.
BORE THIS HOLE OUT TO 3/4" AND 1" DEEP. WHEN APPROACHING THE FINAL BORE DIAMETER CHECK IT AGAINST THE
SHAFT TO OBTAIN A TIGHT BUT NON-BINDING FIT. PUT A SLIGHT CHAMFER ON THE END OF THE SHAFT SO IT
WON'T BIND ON ANY INTERNAL RADIUS AT THE BOTTOM OF THE BORED HOLE.
TURN DOWN THE OUTSIDE OF THE SHAFT TO A DIAMETER OF 1 1/2" X 1" LONG.
CUT OFF TO AN OVERALL LENGTH OF 1 3/8".
3.
THE SHAFT
***********************************insert photo when available - link drawing when available**************
3/4" X 12" BRASS SHAFTING.
FACE OFF AND CHAMFER BOTH ENDS.
DRILL AND TAP ONE END 3/8 NC ABOUT 1 1/5".
IN FACT DRILLING AS DEEP AS POSSIBLE WITHOUT BREAKING INTO THE SHAFT HOLE
WILL GIVE THE MOST WIGGLE ROOM FOR LATER ADJUSTMENTS.
4.
ADJUSTER BLOCK ASSEMBLY
MATERIAL: 6061 T6 ALUMINUM (1"PLATE) WAS USED FOR EASY MACHINING AND APPEARANCE.
THIS IS THE MOST COMPLICATED PART.
MACHINE TO OVERALL DIMENSIONS AS PER DRAWING AND MARK OUT FOR THE THREE H0LES.
DRILL THE CROSS-HOLE FOR THE COTTER.
DRILL AND TAP THE DIAL INDICATOR MOUNT HOLE.
MACHINE THE COTTER BLANK AS PER DRAWING. IT SHOULD BE A NICE SLIDING FIT IN THE CROSS-HOLE.
FASTEN THE COTTER BLANK IN ITS HOLE AND DRILL/BORE THE SHAFT HOLE.
 
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CARRIER BLOCK WITH COTTER BLANK IN PLACE.
DRILLING SHAFT HOLE.
SHAFT HOLE COMPLETE - COTTER BLANK REMOVED.
THE NEXT OPERATION IS TO CUT THE COTTER BLANK IN HALF, MACHINE OFF THE FLANGE
AND DRILL A 1/4" CLEARANCE HOLE THROUGH ONE HALF.
5.
DIAL GAUGE HOLDER/ADJUSTER ASSEMBLYMATERIAL:
-----3/8 X 6" SHAFTING. DRILL ROD, MILD STEEL - NOT CRITICAL.
----DRILL ROD IS EASIER TO WORK WITH.
-----1/8 X 3"DIA. STEEL DISC.
-----SMALL PIECE OF 1/2" BRASS SHAFTING.
CAREFULLY FACE OFF ONE END OF THE 3/8" SHAFT.
THREAD THE OTHER END 3/8 NC FOR ABOUT 3"
SILVER SOLDER OR BRAZE THE FLAT END TO THE CENTER OF THE DISC.
I CHUCKED THE SHAFT IN THE DRILL PRESS TO FIXTURE IT AT RIGHT ANGLES TO THE DISC.
OTHER METHODS COULD BE USED.
THIS IS **CRITICAL**. ANY WOBBLE WILL AFFECT THE ACCURACY.
CHUCK THE BRASS SHAFT AND DRILL A 1/4" HOLE 1/2" DEEP.
CUT OFF 1/2". REVERSE AND FACE OFF IF NECESSARY.
6.
A FEW WORDS ABOUT THE DIAL GAUGE:
AS YOU MAY HAVE GUESSED BY NOW YOU WILL NEED A MAGNETIC-BACKED DIAL GAUGE.
THIS MAKES ADJUSTMENTS EASY AND AVOIDS WRECKING IT WHEN YOU FORGET IT IS THERE
AND RAISE THE QUILL TOO MUCH.
AS I DID NOT OWN ONE AND THEY ARE NOT EXACTLY CHEAP I MODIFIED A GAUGE IN MY COLLECTION.
I USED 'RARE EARTH' MAGNETS (AVAILABLE FROM SEVERAL SOURCES - ONE BEING LEE VALLEY TOOLS).
THE ONES SHOWN IN THE PHOTO BELOW ARE 1/8 X 1/8" RODS.
THESE PROVED TO BE ADEQUATE BUT JUST A LITTLE TOO WEAK.
I WILL BE REPLACING THEM WITH THE NEXT LARGER SIZE. (1/4 X 1/4)
I FABRICATED A STEEL BACK FOR THE GAUGE TO REPLACE THE ORIGINAL BRASS ONE.
AFTER ARRANGING THE MAGNETS I USED LOCTITE™ SUPER GLUE (PART#XXXXXX)
WHICH IS A 'WICKING'ADHESIVE. THE MAGNETS ARE ARRANGED N/S/N/S
THEY WILL ASSUME THIS ARRANGEMENT AUTOMATICALLY.
OTHER SIZES, STYLES OR ARRANGEMENT OF MAGNETS CAN BE USED. WHATEVER WORKS FOR YOU.
THE PHOTO ALSO SHOWS THE EXTENSIONS THAT ARE NECESSARY.
THE ONE ON THE DIAL INDICATOR IS PART OF A SET THAT WAS ORIGINALLY PART
OF A BORE GAUGE
THE LARGER ONE BELOW IS SHOP-MADE.
THE STANDARD THREAD (MODERN) SEEMS TO BE 4/48.
YOUR MILEAGE MAY VARY.
THESE EXTENSIONS CAN BE PURCHASED AS A SET.
ANY COMBINATION THAT ADDS UP TO THE TOTAL TRAVEL OF YOUR QUILL SHOULD BE ADEQUATE.
ASSEMBLY PROCEDURE:
REMOVE THE BELT HOUSING COVER.
HOLD THE SOCKET MOUNTING BRACKET HARD AGAINST THE COLUMN CASTING AND AGAINST THE UNDERSIDE
OF THE BELT HOUSING. A STRONG-BACKED HELPER OR A SUITABLE CHUNK OF SHAFTING BRACED AGAINST
THE TABLE WILL MAKE THIS EASIER.
USING A #7 DRILL BIT;
DRILL INTO THE COLUMN THROUGH ONE OF THE OUTSIDE HOLES
IN THE BRACKET.
ONCE YOU HAVE A GOOD SPOT REMOVE THE BRACKET AND DRILL THROUGH THE (THIN WALL)
OF THE HEAD CASTING.
**DRILL CAREFULLY AS THE DRILL WILL SUDDENLY DROP THROUGH THE HOLE
AND THERE IS A POSSIBILTY OF SNAGGING A WIRE OR TWO INSIDE THE HEAD.**
TAP THIS HOLE 1/4 NC.
USE A TAPPPING BLOCK - THE CASTING IS VERY THIN AND
ANY MESSED UP THREADS WILL SERIOUSLY WEAKEN THE ASSEMBLY!
OPEN UP THE HOLE YOU USED IN THE BRACKET TO 1/4" AND BOLT THE BRACKET TO THE COLUMN.
PROCEED AS IN THE ABOVE TO DO THE OTHER TWO HOLES AGAIN KEEPING THE BRACKET TIGHT
AGAINST THE HEAD CASTING AND THE BELT HOUSING.
BE VERY CAREFUL TIGHTENING THE BOLTS - YOU DO NOT WANT TO STRIP THESE THREADS!
SHOULD THE UNTHINKABLE HAPPEN AND YOU DO STRIP A THREAD ALL IS NOT LOST.
IT WILL BE NECESSARY TO DISMANTLE THE MILL HEAD TO GAIN ACCESS TO
THE INSIDE OF THE CASTING. THEN USE A NUT TO SECURE THE BOLT(S).
LOWER THE HEAD AS FAR AS POSSIBLE AND DRILL DOWN THROUGH THE BELT HOUSING
AND THROUGH THE BRACKET.
YOU WILL NEED TO USE SOME INVENTIVE MEASURING TO DETERMINE WHERE TO LOCATE THIS HOLE
TO GET IT TO COME THROUGH THE BRACKET MORE OR LESS CENTERED.
START WITH A SMALL DRILL BIT (1/8 OR SO) EVENTUALLY OPENING IT UP TO 3/8". CAREFULLY REMOVE ANY BURR
FROM THE HOLE IN THE BOTTOM OF THE BELT HOUSING.
MAKE UP A SHORT (1 INCH) DUMMY SHAFT DRILLED AND TAPPED 3/8 NC.
DROP THE DUMMY SHAFT INTO THE SOCKET AND BOLT IT TO THE BRACKET.
DRILL (#7) DOWN THROUGH THE TWO HOLES IN THE SOCKET FLANGE THROUGH THE BRACKET.
REMOVE THE SOCKET AND TAP THE TWO HOLES IN THE FLANGE 1/4 NC.
OPEN UP THE TWO HOLES IN THE BELT HOUSING/BRACKET TO 1/4" AND BOLT THE SOCKET BACK ON THE HOUSING.
REPLACE THE BELT GUARD COVER
USING A SUITABLE PIECE OF 3/8 SHAFTING (OR A 3/8 DRILL BIT) MARK THE INSIDE OF THE BELT HOUSING COVER.
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REMOVE THE COVER AND DRILL A 1" HOLE IN IT.
REMOVE THE DRAWBAR AND MACHINE THE TOP FLAT - LATHE, DISC SANDER OR WHATEVER IS HANDY.
I USED A DISC SANDER AS THE WELD ON THE TOP OF THE DRAWBAR CAN BE QUITE HARD.
THE MORE PRECISE AND POLISHED FLAT THE GREATER THE ACCURACY OF THE ATTACHMENT.
REPLACE COVER AND BOLT FULL SIZED SHAFT INTO POSITION - DONE!
A FEW NOTES ABOUT USAGE:
THE SHAFT MAY BE LEFT IN PLACE ALL THE TIME EXCEPT WHEN CHANGING BELTS/SPEEDS.
FINAL ACCURACY WILL OBVIOUSLY DEPEND ON THE ACCURACY OF THE DIAL GAUGE USED.
MAKE SURE THAT THE DIAL GAUGE IS CENTERED ON THE TOP OF THE DRAWBAR
AND IS VERTICAL
WHERE POSSIBLE APPROACH THE FINAL READING BY RAISING THE QUILL.
MOST DIAL GAUGES WILL MEASURE A RISE MORE ACCURATELY THAN A FALL.
TAKE ALL INITIAL AND FINAL READINGS WITH THE QUILL LOCKED.
EXPECT ACCURACY (REPEATABLE) OF .0005" !
IF YOU NEED MORE ACCURACY THAN THIS YOU ARE USING THE WRONG MACHINE!
YOU WILL HAVE TO MODIFY YOUR METHOD OF LOOSENING THE DRAWBAR BY
SLAPPING IT WITH A HARD HAMMER. USE A BRASS OR LEAD HAMMER TO
AVOID MESSING UP THE NICE FLAT ON THE TOP OF THE DRAWBAR.
*DO NOT* TURN THE MACHINE ON WITH THE DIAL INDICATOR IN CONTACT WITH THE DRAWBAR!
THIS COULD PROVIDE TOO MUCH EXCITEMENT OR BE DAMAGING AND HAZARDOUS TO YOUR HEALTH !