The Barranca GP6-6 runs six 6" x 1 1/2" wheels on a 5/8" shaft, mounted directly on the motor shaft: two metal bond wheels at 80 and 180 grit for shaping, and four Nova resin wheels at 280, 600, 1,200 and 3,000 for smoothing. A 1" bore wheel fits with a 5/8" bushing. Our SuperNova soft wheels ship with that bushing in the box. Worn Nova wheels from a Barranca can be sent to us for resurfacing.
What each machine ships with
| GP6-6 | GP8 Super | |
|---|---|---|
| Wheels | 6" x 1 1/2" | 8" x 1 1/2" metal bond, plus 8" x 3" belts |
| Hard (brazed metal bond) | 80 and 180 grit | 80 and 180 grit |
| Soft | Nova resin wheels, 280, 600, 1,200, 3,000 | Resin bond mesh belts, 400, 600, 1,200, 3,000, on an 8" x 3" drum |
| Arbor hole | Listed as "1" - 5/8"" | 1" for the metal bond wheels |
| End | 5 1/2" Nova disc, 14,000 grit, 1/4"-20 | 8" leather disc and 8" convex hub |
| Motor | 1/3 HP, 1,800 RPM | 1/2 HP, 1,725 RPM |
Sources: Barranca Diamond product pages and lapidary catalog. The GP6-6 shaft is 5/8" with wheels mounted directly on the motor shaft, per the Barranca manual.
Fitting a 1" bore wheel to a 5/8" shaft
The GP6-6's soft wheels are Diamond Pacific Nova wheels. Our SuperNova wheels are made with a 1" bore and ship with bushings for 3/4", 5/8" and 1/2". On a GP6-6, use the 5/8" bushing. Spare telescopic bushings are sold separately.
Never run a 1" bore wheel on a 5/8" shaft without the bushing. That is 3/16" of clearance on each side. The wheel will run off center, wear in a band and put the load on the motor bearings. See Arbor and bore sizes.
Replacing each position on the GP6-6
Positions 1 and 2, hard wheels. Barranca ships 80 and 180. None can be resurfaced.
| Wheel | GP6-6 |
|---|---|
| Our nickel bond hard wheel | 6" x 1 1/2" in 80, 100, 180, 220, 360, 600 grit. The stock 80 and 180 are both available |
| Our sintered wheel | 6" x 1 1/2", 30 to 600 grit |
Both hard wheels are 1" bore. On a GP6-6, fit a 5/8" bushing.
Positions 3 to 6, soft resin wheels. Resurfaceable, any brand.
| Wheel | GP6-6 |
|---|---|
| SuperNova, made in our Orange, CA warehouse | 6" x 1 1/2", 1" bore with 5/8" bushing included, in 280, 600, 1,200, 3,000 and 12 other grits |
| Diamond Pacific Nova, the stock wheel | 6" x 1 1/2" |
End disc. The GP6-6 ships with a 5 1/2" 14,000 Nova disc on a 1/4"-20 mount. Our SuperNova disc is 5.5" with a 1/4"-20 screw back, in 280 to 50,000 grit including 14,000.
The GP8: belts instead of soft wheels
The GP8 Super does its smoothing on 8" x 3" resin bond belts over an expandable drum, not on soft wheels. We sell belts and a drum in that size:
| Item | Size | Grits |
|---|---|---|
| Resin bond diamond belt, made in our Orange, CA warehouse | 8 x 3 | 60 to 200,000, plus oxides |
| Nickel bond diamond belt | 8 x 3 | 70, 120, 220, 400, 600 |
| Silicon carbide belt | 8 x 3 | 36 to 1,000 |
| Expanding drum | 8" x 3" |
All three of our 8" x 3" belts fit the GP8's drum, and any expanding drum of that size. Barranca's stock belts run 400, 600, 1,200 and 3,000. Our resin bond diamond belt covers 600, 1,200 and 3,000; it does not come in 400. The GP8's hard wheels are 8" x 1 1/2" with a 1" hole. Our nickel bond hard wheel comes in 8" x 1 1/2" in 80 and 180 grit.
Resurfacing Nova wheels from a Barranca
The GP6-6's four soft wheels are Nova wheels, and Nova wheels can be resurfaced. Ship the wheel only, and keep the 5/8" bushing on the bench. It comes back in about a week.
| Wheel | Resurface | New SuperNova |
|---|---|---|
| 6" | $39.95 | $79.95 |
Prices from the live store, 2026-09-29. Change the grit at no extra charge if you want a different one back. The brazed metal bond wheels in positions 1 and 2 are not resurfaced. Belts are not resurfaced.
A worn soft wheel. This is what we resurface. See resurfacing Nova wheels.
Questions we get
What size is the Barranca GP-6 shaft?
5/8", with the wheels mounted directly on the motor shaft.
Will a 6" SuperNova fit my GP6-6?
Yes, with the 5/8" bushing that comes with it. Same 1 1/2" width as the stock wheels.
Can you resurface the Nova wheels off my Barranca?
Yes. Nova is a soft resin wheel, and we resurface soft wheels from any maker.
Can you resurface the 80 and 180 wheels?
No. They are brazed metal bond hard wheels.
My GP8 uses belts. Can those be resurfaced?
No. Resurfacing is for soft wheels. Belts are replaced.
Related: Arbor and bore sizes, Resurfacing Nova wheels, Grit progression for cabbing.