Parallels, or setup blocks, are essential for ensuring true, repeatable positioning in milling and drilling work. The right set combines hardness, squareness, and multiple holes for clamping options, enabling precise machining with less setup time. Below you’ll find five top-performing parallel block sets that span common sizes and hole patterns, helping you select the best match for your milling needs in a typical American workshop.
Summary table of chosen products (highlights only):
| Product | Brand | Common Size | Accuracy | Holes |
|---|---|---|---|---|
| 1-2-3 Parallel Blocks (5 matched pairs) | TJHSM | 1″ x 2″ x 3″ | 0.0002″ per inch | 23 holes per block |
| 1 x 2 x 3 Blocks Set (23 Holes) | marddpair | 1″ x 2″ x 3″ | 0.0003″ per inch | 23 holes |
| LABLT 1 x 2 x 3 Block Set | LABLT | 1″ x 2″ x 3″ | 0.0002″ squareness | 23 holes |
| 2 x 4 x 6 Block Set (23 Holes) | marddpair | 2″ x 4″ x 6″ | 0.0003″ per inch | 23 holes |
| 1-2-3 Inch Ultra Precision Set (1 Pair) | YKWYKW | 1″ x 2″ x 3″ | 0.0002″ | 23 holes |
1-2-3 Parallel Blocks, 5 Matched Pairs
- Durable: All six sides hardened to HRC 57-62 for long-lasting use.
- High precision: Precision-grade tool steel with grinding; verticality accuracy within 0.0002″ per inch.
- High strength: Cross drilling design minimizes weight while maximizing strength.
1 x 2 x 3 Blocks Set 23 Holes
- Accuracy: 0.0003 inch; hardened steel, heat treated and case hardened to HRC 57-62.
- Cross drilling design for lower weight with maximum strength.
- Ensures squareness on all sides within 0.0003 per inch.
WFLNHB 10 Pair 1/8″ X 6″ Parallel Bars
- Includes ten pairs across multiple heights with a storage case for organization.
- Each bar is 1/8″ thick by 6″ long with two holes for clamping versatility.
- Convenient kit for broad milling setups and quick changes.
LABLT 1 x 2 x 3 Inch Block Set
- Made of precision-grade tool steel, hardened and ground on all sides.
- Heat treated and case hardened to HRC 55-62; squareness within 0.0002 inches.
- 23 holes, including 5 tapped holes for clamping and 18 untapped holes.
2 x 4 x 6 Block Set (23 Holes)
- Size: 2″ x 4″ x 6″; precision: 0.0003 inch accuracy per side.
- Hardened steel, heat-treated and case hardened to HRC 57-62.
- Cross drilling supports efficient clamping with balanced strength.
1 Matched Pair 1-2-3 Inch Ultra Precision Blocks
- Precision steel construction for accurate drill block setups and milling work.
- Hardened steel with durable construction; designed for long-term use in shop environments.
- Targeted for accurate measurements when drilling round parts or pipes.
Buying Guide: Key Considerations For Choosing Parallels
When selecting parallels for a milling machine, consider how the block set will fit your workflow, tooling, and material types. The following perspectives help ensure you pick a kit that balances accuracy, ease of use, and value:
- Material and hardness: Opt for hardened tool steel with corrosion resistance. Look for hardness in the HRC range of mid-50s to mid-60s to endure repeated clamping without deforming.
- Squareness and accuracy: Check stated squareness on all sides and the overall accuracy per inch. Smaller tolerances (e.g., 0.0002″ to 0.0003″) improve repeatability in milling setups and reduce misalignment risk.
- Hole patterns and tapped options: A consistent 23-hole layout across blocks provides flexibility for clamping and alignment. Tapped holes (e.g., 5/16-18, 3/8-16, 5/8-11) add clamping versatility and speed up setups.
- Size variety: Common starter sizes are 1″ x 2″ x 3″ and 2″ x 4″ x 6″. A mixed set with multiple sizes covers most milling scenarios, from small fixtures to larger workpieces.
- Weight and cross drilling: Cross drilling reduces weight while maintaining strength, improving ease of handling on busy workbenches and reducing tool pressure during clamping.
- Storage and organization: A durable case or tray helps prevent loss of holes or misplacements, crucial for maintaining accuracy during long-term use.
- Value versus future needs: If you anticipate expanding your milling operations, invest in a 2″ x 4″ x 6″ set alongside 1″ x 2″ x 3″ blocks to cover wide workpieces and modular setups.
- Maintenance: Clean and lightly oil blocks after use to prevent rust and ensure smooth movement when aligning parts. Inspect for any wear or burrs that could affect accuracy.
- Compatibility with accessories: Ensure your blocks work with your existing vises, clamps, and post-mounted rulers. Compatibility reduces the need for supplementary adapters.
Overall, a high-quality 1″ x 2″ x 3″ set with 23 holes is a strong foundation for most hobbyist and professional shops, while including a larger 2″ x 4″ x 6″ set adds versatility for bigger fixtures. Prioritize blocks with consistent squareness, solid hole patterns, and robust cross-drilling designs to maximize precision and workflow efficiency.