Jack Cole Ph. 503-510-0789
Some of the toys in the shop, I use to turn rock to mud.
1978 Chevy Camper special 15/16 rock hunting partners.
1982 Highland-Park slab saw ( 24 Inch Blade ).
Best to run at 6- 8 minutes to the inch! on MOH-scale 7 or harder.
Though to re face a blade high speed is about 4 minutes to inch. with a block of Obsidian to clean the blade.
reveres the blade often to clean the back ramp of matrix that builds up on the back side of the diamond in the matrix of the slot. ( Natch blades by MK-.com ) Are the ONLY Blade out there for my saws. ( 297 - 301 - 303 ) Gem-King.
I only use 220 grit or finer on the lap. I per-face all material of saw marks and break off edge, before lapping flats.
24 Inch home made buff pad. with Lamb wool carpet pad. 265 RPM.
18 inch steel rotary lap. ( 178 RPM ) Lebanon,Oregon millwright built this lap mid-60s and i have used a lot of other rotary laps, they bog down burn motor out bearing ware.....long list of why you should build your on lapidary equipment.....
Every bolt is grade 8 with Allen hex head bolts. Ive had it over 20 years. Never a belt change and several hundred ponds of Brazilian agate per-polished on it for the 27'' Highland-Park Viber-laps.
Highland-Parks Combo-unit Model E-10 year 1955.
Though you see the upgrade i made. Nova 8'' diamond plated wheels, 80 grit - 120 grit - 320 grit
I still have the wore out 9'' Highhland-Park black diamond blade it came with. Now 303 MK-Blade 8'' gem-king.
Home made tumbler, drum is 11'' x 24'' center shaft Babbitt bearings 1/2 Hp. motor. Drum RPM - 16. Load limit depends on material 2/3 - 3/4 about 50 - 60 Lbs.
I use this one for rough grind of material. such as fire agate rough, carnelian agate, Sheen obsidian rough to cut the Patina off the surface, to zone the material for sheen cut.
Viking VT-12 - Commercial Vibratory Tumbler & Vibra Sonic Tumbler - VSV-50.
Both of these I only use 220 grit or finer. Rotary to rough cut the material, Then vibra sonic to finish. I use each grit much longer then the tumbling world does!( 220 grit for 3 weeks grinds down to 1200 grit in 2nd week in loads heavier then 15 lbs. )
Covington Large Sphere Machine 1''1/4 x 9'' Spheres. Rough cut 80 grit only. 80 grit is classified to size. Or finer grit.
To speed up surface cut I grind dime size flat spot all over the surface of the sphere. and i use cup size of 1/2 - 2/3rds the length of spheres diameter, for rough cutting the surface grind with 80 grit. for truing the sphere, Use 1/4 - 1/3 cup size of diameter for finish of sphere before the polish stage with different cups only for use with polish.
10 inch grinder / with old 10'' drum. Sand paper is belt strips their about a 34'' x 3''. Arbor shaft is 1-1/8th in. The same millwright at work.
Rotary tumbler grit for rough grind 80 grit. The 80 grit turns to 400 grit in about 3 weeks in this tumbler.
mix grades like 60/90 - 40/70. MOH-Scale 7 higher in hardness !!! - Principle at School of hard - Knocks, Obsidian - softer material. adjust grit as needed. sometimes 220 grit for rough cut - finer. Vibra - sonics use less then a ounce of water KEEP the rock much dryer for faster cut.
50 Years later still playing in the rock pile.