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robertsilas.com

HORIZONTAL MILLING MACHINE.

During a monthly meeting of the Canadian Vintage Motorcycle Group I was discussing milling machines with one of the club-mates. I happened to mention that I would like to find a small horizontal milling machine, if it existed in a small version at all. Horizontal milling machines are rarely used vertical millers took over the industry.

 

To my great surprise this club- mate of mine said that he had a friend who had such a miller and it was for sale. Wasting no time, the next day I called the owner and arranged a viewing of the machine. With some cash and the trade of a band saw I became the happy owner of a horizontal milling machine.   The machine was in poor condition; needed a lot of work.

 

This horizontal miller’s birth-date is dated back before or during WWII. This machine was fabricated in Leicester, England by Adcock & Shipley; it is a 1940 design.  All that information was found by another club-mate, on the net, well after the machine’s re-building and modification were done.

 

The first picture shows the machine in use, obviously, in the 1940s; the operator has no protection at all. All three movements of the table were done by lever actions.

 

The second picture reveals the condition of the machine at the time of purchase and that a previous owner of this machine had already converted the X and Y movements of the table from lever actions to hand operated screw-shafts. The vertical, the Z, direction still had the hand operated lever action. Beside a total reconditioning this last change was waiting for me.

 

The first job was the complete disassembling of the machine except for the upper and lower pulley assembly. Rust had to be removed, old pealing paint had to be removed. The condition of the machine did not require any new parts or bearings, cleaning and re-painting would have been sufficient if it were not for the modification of the vertical movement.

 

Besides the modification of the vertical movement there was need for a new  stand to support the whole machine, and to save space, the motor had to be placed under the machine within the stand, just below the driven pulley. The old location of the 1.0 HP 110 V motor is visible in the third picture

 

Before any further work I had to make a drawing, a design for a 90 degree drive to raise and lower the machine’s table. The location of the drive had to be within very little room, inside the bottom of the casting; therefore the pair of bevel gear for it had to be small. I bought two identical gears, 15 teeth on each. The design of the drive is shown in the fourth picture.

 

In spite of its size this is a very sturdy machine of cast iron body and tray, as is visible on the fifth picture. I did not weigh this mill but according to my estimation it is over 500 pounds.

 

Pictures 6 to 9 show milling out a space for a bearing nest from the bottom of the machine’s table and the block of steel, which will be the nest of the vertical spindle’s bearing. The fastening of the nest-block into position is also shown. The place for the bearing in the nest-block is not yet machined out at this point.

 

On picture 10 the machining of the bearing nest, for the horizontal spindle, is visible. The new gears and bearings have to be protected from falling metal shavings. For that purpose a piece of thin galvanized plate was fitted over the 90 degree angle drive, as shown on picture 11. On picture 12 both complete bearing nests are shown in their final positions.

 

Because of the limited space for the bevel gears, the hub of the gear had to be fitted directly into the bearing. The inside diameter of the bearing is 25 mm but the hub of the gear is 1.0” = 25.4 mm. The material of the gear was so hard that it could only be ground to make it fit into the gear; it is shown on picture 13.

 

Another problem was to drill a stepped hole, a seat for the “ bronze nut, into the cast iron base of the machine. The swing of the drill press was not big enough to reach the place of the hole in the base-tray of the machine. The stepped-hole carries the weight of the whole machine table assembly.

The use of a 1.25 and a 1.5 inches diameter hole-saws with carbide teeth and a magnetic drill press did the job. For finishing the seat a fly-cutter was used. Pictures 14 and 15 show the pieces needed to make the seat and the installed bronze nut.

 

Parts shown on picture 16 are ready to be assembled. The machine was carried to its final location in parts and they were assembled there.

In picture 17 the vertical spindle/screw screwed into the bronze nut, with the assembled bearing nest on top of it.  The table will be lowered onto it. 

 

For the table lifting/lowering screw  a inch diameter x 10 pitch, commercially available, threaded rod was used. A pitch of 10 means that one turn of the shaft will move the table by 100 thou, a very convenient number for a dial of the crank. Since the vertical screw and the horizontal shaft are connected by bevel gears of the same number of teeth, for one turn of the vertical screw the horizontal shaft has to be turned by one turn too.

 

This x 10 rod is right hand threaded which means that the horizontal spindle with the hand crank, has to be rotated counter clock wise to lift the table. Of course it should have been a left hand threaded screw, according to general practice, but it is only a matter of getting used to it. The readymade screw-shaft saved a lot of work.

 

Pictures 18 and 19 refer to making divisions on the dial of the horizontal crank. A 100-tooth gear was attached to the end of the lathe spindle. A long neck air-grinder was attached to the tool post of the lathe.

By using a carbide tip at 25,000 rpm the division lines were engraved into the perimeter surface of the dial.

 

Adding numbers to the division lines was the next task. Engraving companies, CNC machining firms etc., refuse to do that job. It had to be another project.  Pictures 20 to 23 deal with this problem.

 

To do a decent job a tool had to be made, which would position the numbers accurately with equal depth of indentation of each. A block of aluminum was purchased; a 30” long pipe was found at home. To ensure accurate locations for the numbers a dial was made on the computer and glued onto the face of the dial. For identical indentation a plunger had to be dropped on the number-punch, from the same height for each punch. Not to ruin the dial, test number-punching had to be done. With a string over a pulley on top of the tube the plunger was raised and dropped. For the required indentation the plunger’s height was established by trial and error. After the plunger hit the letter punch it bounced up and down a few times. To stop that 12 pieces of earth-magnets were placed beside the plunger. They did the job. When the plunger bounced back the magnets kept it at the top of its bounce.

As a further advantage the magnetized plunger drew the number punch up with it, so it was easy just to grab it and change it with the next one.

 

Pictures 24 and 25 refer to the fabrication of a hand crank for the horizontal shaft.

 

Picture 26 shows the original speed ranges of the machine. There are 6 sets of pulley arrangements and a transmission to shift gears between Fast and Slow. This combination gives steps between 180 to 3600 RPM. Originally the motor was flange mounted directly driving the lower pulley’s shaft. At the time of purchasing this machine the drive was already modified to a separate motor and V-belt.

 

Picture 27 The A to Z rebuilding, with one helper, took a whole winter to complete. This machine is a work horse; it is sturdy, no vibration, works very well though it is not as often needed as a vertical mill but when there is a job for it, it does it better than the vertical mill.