HTML> Diamond facet head           "DIAMOND CUTTING BY AN AMATEUR"

                 The Hartley Diamond Faceting Machine Modified.

                                                      By Larry W. Davis


A word of caution:

Due to the nature of the materials which are used in this project and the speed which they operate;
the author must give warning that extreme danger is involved with use of the equipment.  I take no responsibility for anyone who makes a copy of any part of this machine and then attempts to sell or use it in any way.

I have simply tried to recreate an interesting machine from the past and in no way do I recommend that it be used.  It is strictly an attempt at a machine shop project.

The completed lap assembly will weigh in at between 50 and 75 lb..  Running it at full speed will mean that you are turning an extreme mass at a very high speed.

The machine will operate in excess of 1,750  rpm...  As the cutting lap used is made of cast Iron which will crack and scatter like shrapnel and use of the safety lap is highly recommended, even required.

If you take it upon yourself to make a copy of this machine fine.  But if you use it you must have a DEATH WISH and you are entirely on your own.   I will not use it myself.  My copy has been stored and partly dismantled since the show where it was displayed.

L. D.


The original idea for this facet machine was taken from a series of articles in the 1967 Lapidary Journal.  Mr. Donald W. Hartley described the construction and use of his machine.  It was the first
home made machine which I had ever seen which could cut diamond.

Here you will find a series of photographs which show how I have reconstructed the Hartley machine and modified it to use a modified RayTech Shaw facet head having a diamond holding claw and pivoting yoke assembly to replace the Hartley claw assembly.  This will allow the individual to adapt a readily available and well made commercial facet machine head .

The entire project was completed in a little over three months from the start at a cost of just under $1,000.   Much of the more detailed and complex work was farmed out to a local machine shop and the modification of the RayTech head was completed by the author.

If anyone would like further details on how the machine was designed and a set of measurements please contact me at my e-mail address    faceter@gte.net

In all cases as I found the standard commercially used measurements for laps, spindle and bore holes to be very well designed and to pass stress requirements I have attempted to use the commercial size measurements.

No attempt has been made to show all of the details such as the mounting slide rails which the head
moves on during adjustment.  Details of this nature may vary from person to person during construction and are considered personal preference items.

After the show I did charge the lap with 50,000 grit diamond grit and olive oil.  Then I mounted a broken one ct diamond and cut two faces on the stone.

The machine will work if you want.   You have to adjust for the grain direction in the diamond and will find many sparks flying off the lap along with a good deal of squealing and perhaps some new words coming from your own mouth when the sparks fly.


 


 The author at right demonstrating the faceter to Mr. Roy Justice at
the April 1989 Wichita Gem and Mineral show in Wichita, KS.


The mounted head and lap assembly with the head locked in the up position.

Close up of the modified RayTech head with diamond clamping claw in place holding
a stone while cutting.  In this case the stone was a CZ used for demonstration purposes.

The lap is 12 inches in dia. and a finished 5/8 inch thick having a 22 mm dia spindle hole.

Shown under and surrounding the cutting lap is a safety lap consisting of a hogged out plate
of Aluminum stock cut to allow just 1/8 inch of the cutting lap to protrude above the safety lap.

The entire assembly was balanced as well as possible.  They will run at an extreme speed of
near 30,000 rpm and will throw a good bit of wind out to 3 feet from the laps.

Head in cutting position on lap.

Head shown in locked position "UP" for safety.

Note the height adjustment locking lever and nut just under
the double handle at upper left.

The un-mounted head.  All of the aluminum stock used in the actual head
is 1 inch thick.  The mast is 1 inch dia. steel and the base plate is 1 inch
thick steel.  It is heavy enough to stand by itself as shown not requiring
any hold down at all.  (Not in use.  There it must be clamped down)

Close up of the RayTech head and pivot yoke assy..  The yoke was constructed
from strap iron heated, bent and welded to shape.


Quill removed and shown from the protractor side.
Diamond claw clamp shown  Dop left out.

Detail of the hogged out safety lap.


 

Motor and turnbuckle.  The pulleys are the three part bolted type.

The top bearing assy. with the drive shaft shown installed.

The drive shaft is 1 inch dia turned down to fit the 3/4 bearing and further
turned to 22 mm to fit the lap.

Note the grease fitting.  This is a must.

Drive shaft shown with the step down pulley.   The lower bearing assembly is
the same kind used on the top but is mounted on a pair of angle iron rails with
slotted holes so that the shaft can be adjusted for perpendicular.  It too has
a grease fitting.  Both top and bottom bearings must be high speed type and they
still will be very hot after running.  You should only use the best components that
money can buy.