Checked 22 September 2026
Barranca GP-6 and GP-8 cabmakers
Barranca Diamond sold the GP-6 Cabmaker with several sets of wheels, belts and pads, so check which ones a machine has before you buy it or order parts. The GP-8 is a larger machine with eight-inch wheels and a one-inch shaft.
Start with the model and part number
A Barranca part number names a package, not just a cabinet, and the package behind a number has changed over time. Barranca's 2004 GP-6 page listed the carbide-wheel GP-6 as 8300046 and the diamond-wheel GP-6 as 8300048, with motorless versions as 8300047 and 8300049.
MK Diamond now sells Barranca machines. Its carbide-wheel listing keeps 8300046. Its 2022 GP-6 manual calls 8300048 the belt model, which still has diamond wheels but now four resin belts, and adds 8300052 for a pad model. Neither "GP-6" nor a part number alone tells you which wheels, belts or water parts to order. Read the plate, then compare the shaft, stations and accessories with the matching manual.
The abrasive package changes the workflow
The current carbide-wheel GP-6 comes with 100- and 200-grit silicon-carbide wheels, a six-inch expanding drum, resin-bond diamond belts, polishing pads, a pump and water valves. MK Diamond lists a ⅓-horsepower, 1,725-rpm motor. Silicon-carbide wheels wear and need dressing; the belt and polishing stages use different consumables.
The 2022 manual's specification for the belt and pad models lists 80- and 200-mesh diamond wheels, four 6 × 1½-inch resin belts and a matching drum. The pad model adds nine five-inch diamond pads with a rigid and a rubber backer. Older machines differ: the 2004 diamond-wheel package paired 400- and 600-mesh metal-bond belts with 1,200- and 3,000-mesh resin belts, and Barranca sold the motor, mount and switch for motorless cabinets as a separate Power Pack (8300288). For a used machine, ask for photographs of both ends of the shaft, the motor plate, the drum width and every included head.
Match replacement abrasives by measured diameter, width, bore and mounting system. The 2022 manual gives the GP-6 a ⅝-inch shaft, so a wheel with a one-inch hole needs a bushing. A six-inch wheel and a six-inch belt are not interchangeable, and a polishing pad may need a dedicated backer. The wheel and drum guide explains those measurements.
The GP-8 is a separate machine
Barranca's 2004 GP-8 page lists part 8300050 with a one-inch stainless-steel shaft, a ½-horsepower, 1,725-rpm motor with a drive belt, 80- and 200-grit 8 × 1½-inch diamond wheels and two 8 × 3-inch expanding drums. The 2022 GP-8 manual describes package 168077: a direct-drive ½-horsepower motor, 80- and 170-grit wheels and one 8 × 3-inch drum on a one-inch arbor.
Check which drive a used GP-8 has before ordering a belt, pulley or motor coupling. Its parts do not match the GP-6's: the 2022 manuals give the GP-8 a one-inch shaft against the GP-6's ⅝ inch, and a different pump part number.
Check the water path and the complete drive
Inspect the pump, hose, valves and drainage with water running. Check bearings and wheel runout, belt tracking, shaft threads, guards and electrical protection. Ask for the machine's part number and manual revision, then find the matching document in the MK Diamond manual and parts index. Matching a part from a photograph of a similar cabinet is less reliable.
Price missing diamond wheels, belts, pad heads and pump parts before comparing a bare used cabinet with a complete cabber. The combination-machine guide covers the same problem on mixed saw-and-grinder units.
Manuals and parts lists
MK Diamond's lapidary manual index links a Barranca Diamond owner's manual and parts list for each model. All three are dated January 2022. Match the model and serial number on the machine's plate before using a parts drawing.
- GP-6 Cabmaker: owner's manual, revision 108 (PDF) and parts list (PDF). Both cover the belt, pad and carbide-wheel models.
- GP6-6 Wheel Cab Maker: owner's manual with parts list, revision 104 (PDF). It lists two brazed diamond wheels and four Nova resin wheels, all 6 × 1½ in.
- GP-8 Super Cabmaker: owner's manual, revision 106 (PDF) and parts list (PDF). They cover the machine with the basic and the full accessories package.
Read the GP-6 manual's motor section before running an older machine. Page 29 says motors on belt models before serial number 0000750, and pad models before 001700, have no reset switch and restart by themselves once cool. If such a motor stops, switch it off at once.
For a part the drawings do not identify, contact Barranca Diamond through the details in the manual. Have the model, serial number and photographs of the assembly ready. Manuals for other makers' machines are listed on the parts and manuals page.