Skip to content
Equipment Fitment & Selection Assistance | Delivery to the 48 Contiguous States | U.S.-Based Phone and Email Support
Equipment Fitment & Selection Assistance | Delivery to the 48 Contiguous States | U.S.-Based Phone and Email Support

8274-4 Planetary Grinder | National Flooring Equipment

Original price $13,982.60 USD - Original price $13,982.60 USD
Original price
$13,982.60 USD
$13,982.60 USD - $13,982.60 USD
Current price $13,982.60 USD
Authorized Dealer Sourcing
Financing Available for Eligible Orders
Contractor-Grade Equipment

The 8274-4 is an 18.5 in planetary grinder that preps and polishes concrete to a 3000-level polish on a 3 HP motor. A built-in soft start controls amperage draw and an upgraded box lets a 115 V machine work at a level normally needing 230 V, with amps switchable between 15 and 20.

Need fitment or freight help before you order? Contact us.

Shipping & Freight

We ship to the 48 contiguous states. We do not ship to Alaska, Hawaii, US territories, military (APO/FPO/DPO) addresses or outside the United States.

Smaller items ship by parcel carrier, priced by weight. Larger items and heavy equipment ship by LTL freight, priced by your ZIP code and the delivery type you choose: terminal pickup and dock delivery cost the least, and commercial liftgate, residential liftgate and jobsite delivery each add the carrier’s fee. Your shipping cost is shown at checkout before you pay.

The best way to get a shipping quote or ask a freight question is the Get a Freight Quote button on this page. You can also call (805) 398-6165.

Delivery types, delivery times, terminal pickup, liftgate service and damage inspection are covered in our Shipping Policy.

Compatibility / Fitment

Compatibility varies by product type, machine setup, selected options, and intended application.

For machine-mounted equipment and attachments, buyers should confirm fitment before ordering using the relevant machine information, including model, attachment style, mount type, coupler type, hydraulic requirements, and any other product-specific requirements listed on the page.

Hardscape Heavy can assist with pre-order fitment guidance based on the information you provide. This guidance is limited to purchase and compatibility review before ordering and does not include field installation, hydraulic modification, fabrication, or on-site setup support.

If you are unsure whether a product will work with your machine or application, contact us before placing the order.

Specifications

Core Specs

  • Disk Size: 18.5 in (47 cm)
  • Motor: 3 HP (2.24 kW)
  • Motor Speed: 400 to 2,000 RPM
  • Weight: 388 lb (176 kg)
  • Voltage: 115 V
  • Width: 20 in (51 cm)


Need full technical detail?
See the Technical Details tab. If available, also see manufacturer PDF in the Downloads tab.

Returns & Warranty

Warranty coverage is provided by the product manufacturer where applicable. Warranty terms, coverage periods, exclusions, and claim procedures vary by brand and product type.

Hardscape Heavy does not create separate warranty coverage beyond the manufacturer’s warranty unless explicitly stated on the product page.

Returns: within 30 days of delivery if unused and complete, with a restocking fee of up to 25% plus return freight. Returns need the manufacturer's agreement to take the item back; if they won't, the sale is final. Custom and made-to-order items are final sale. Full terms: Refund Policy.

Please review our full return policy before purchase. If you have questions about return eligibility or manufacturer warranty coverage for a specific item, contact us before ordering.

The 8274-4 is the grinder for a contractor who wants a large machine's output without a large machine's supply. It runs on ordinary building power and, in the supplier's own description, works at a level normally associated with a 230 V machine, which is what puts a high polish inside reach of buildings that have no three-phase drop.

The soft start is the component that makes that possible. Starting a heavy grinding head draws current sharply, and it is usually the start rather than the run that trips a circuit; controlling that draw is what keeps the machine on a standard supply. Amperage is switchable between fifteen and twenty at the controller, so it matches the circuit it finds rather than requiring one.

Adjustable weights and variable speed cover the range of work. Loaded and slow, it takes off thin-set, coatings and adhesive; light and fast, it polishes to three thousand grit. That span is why one machine handles both a small job and a large one instead of the fleet needing both ends.

Common Applications

  • Preparing concrete for overlays and coatings
  • Removing thin-set, coatings and adhesive
  • Polishing concrete to a 3000-level finish

Selection Notes

  • Amperage switchable between 15 A and 20 A at the controller
  • Ships with couplers, quick-change assemblies, adapters and hex keys
  • Three quick-change assemblies and three velcro adapters are required for a full set
Capacity
Disk size
18.5 in (47 cm)
Polish level
Up to a 3000-level polish
Drum speed
133.8 RPM
Motor speed
400 to 2,000 RPM
Unit Specifications
Motor
3 HP (2.24 kW)
Motor phase
Single
Voltage
115 V
Frequency
60 Hz
Amps
15 A or 20 A, switchable at the controller
Build
Soft start
Built in, controls amperage draw
Weights
Adjustable
Speed
Variable
Accessories
Morflex couplers
401882, supplied
Quick-change magnetic-mount assembly
9241, three required with three 73250 mounting screws
Velcro adapter
9245, three required, mounts on the 9241 assembly for polishing pads and brazed disks
Hex key
73135, 5/32 in
T-handle wrench
6280-401B, 7/32
Dimensions & Weights
Weight
388 lb (176 kg)
Width
20 in (51 cm)
Maximum height
52 in (132 cm)
Minimum height
27.5 in (70 cm)
Maximum length
75 in (191 cm)
Minimum length
38.5 in (98 cm)
Built-in soft start
A heavy head starts without tripping the standard circuit it is plugged into
Switchable 15 A or 20 A draw
The machine matches the circuit it finds instead of requiring one
Adjustable weights with variable speed
One machine covers coating removal and 3000-grit polishing

Included with Purchase

  • 1 8274-4 Planetary Grinder (variant/model as ordered)
  • 401882 Morflex couplers
  • 9241 quick-change magnetic-mount assembly
  • 9245 velcro adapter
  • 73135 hex key
  • 6280-401B T-handle wrench

Not Included Unless Stated

  • Diamond tooling, polishing pads and brazed disks
  • Dust collector
  • On-site installation or machine configuration

Note: Confirm exact included components and mount hardware with supplier at time of order.

Related Equipment

M800 Planetary Grinder | National Flooring Equipment

National Flooring Equipment
Original price $34,905.00 USD - Original price $34,905.00 USD
Original price
$34,905.00 USD
$34,905.00 USD - $34,905.00 USD
Current price $34,905.00 USD

The M800 is a 32 in electric planetary grinder for large surface preparation, running a 20 HP motor on 230 V three phase. Automatic planetary lifti...

View full details
Original price $34,905.00 USD - Original price $34,905.00 USD
Original price
$34,905.00 USD
$34,905.00 USD - $34,905.00 USD
Current price $34,905.00 USD

M600 Planetary Grinder | National Flooring Equipment

National Flooring Equipment
Original price $14,002.00 USD - Original price $14,002.00 USD
Original price
$14,002.00 USD
$14,002.00 USD - $14,002.00 USD
Current price $14,002.00 USD

The M600 is a fully geared 23 in planetary grinder and polisher on 230 V, single or three phase, driven by a 5.5 HP motor. It carries adjustable wo...

View full details
Original price $14,002.00 USD - Original price $14,002.00 USD
Original price
$14,002.00 USD
$14,002.00 USD - $14,002.00 USD
Current price $14,002.00 USD

Helix Planetary Grinder | National Flooring Equipment

National Flooring Equipment
Original price $7,237.11 USD - Original price $7,237.11 USD
Original price
$7,237.11 USD
$7,237.11 USD - $7,237.11 USD
Current price $7,237.11 USD

The Helix is a 16 in planetary grinder on 120 V, built to come apart into several pieces so one person can carry it up a stair and fit it in any ve...

View full details
Original price $7,237.11 USD - Original price $7,237.11 USD
Original price
$7,237.11 USD
$7,237.11 USD - $7,237.11 USD
Current price $7,237.11 USD

3432 Handheld Polisher | National Flooring Equipment

National Flooring Equipment
Original price $1,155.36 USD - Original price $1,155.36 USD
Original price
$1,155.36 USD
$1,155.36 USD - $1,155.36 USD
Current price $1,155.36 USD

The 3432 is a 10 lb handheld right-angle polisher taking a 5 in disk, with variable speed from 700 to 2,200 RPM. It ships with a loop handle, a vel...

View full details
Original price $1,155.36 USD - Original price $1,155.36 USD
Original price
$1,155.36 USD
$1,155.36 USD - $1,155.36 USD
Current price $1,155.36 USD

A97 Shot Blaster | National Flooring Equipment

National Flooring Equipment
Original price $28,415.71 USD - Original price $28,415.71 USD
Original price
$28,415.71 USD
$28,415.71 USD - $28,415.71 USD
Current price $28,415.71 USD

The A97 is the largest shot blaster in National's Apex series, a self-propelled variable-speed machine cutting a 10 in path at up to 2,000 sq ft pe...

View full details
Original price $28,415.71 USD - Original price $28,415.71 USD
Original price
$28,415.71 USD
$28,415.71 USD - $28,415.71 USD
Current price $28,415.71 USD

Compare products

{"one"=>"Select 2 or 3 items to compare", "other"=>"{{ count }} of 3 items selected"}

Select first item to compare

Select second item to compare

Select third item to compare

Compare