What Problems Do Reamers Solve?
Reamers are an important type of cutting tool used to enlarge, smooth, and finish holes to precise dimensions and surface finishes. They have a variety of applications across metalworking, woodworking, and other trades. So what are the key problems that reamers can solve?
Achieving Tight Tolerances
One of the primary uses of a reamer is to produce holes that have very tight tolerances. The cutting edges of a reamer are designed to remove just enough material to smoothly enlarge a hole to the desired size. This allows holes to be machined to within +0.001" to -0.000" of the specified diameter.
Deburring and Smoothing Rough Holes
Holes drilled or bored by other tools often have burrs, jagged edges, spiral grooves, and other imperfections. Running a reamer through the hole removes these defects and smoothes out the surface.
Finishing Pre-Drilled Holes
Using a reamer is the last machining step for many holes, providing a high-precision finish size and surface texture. The shearing action of a reamer provides a better finish than an end mill or twist drill. This helps achieve the tightest possible tolerances.
Improving Hole Geometry
- Makes holes straighter and more perpendicular
- Removes taper from drilled holes
- Corrects off-center or egg-shaped holes
Reamers help improve hole geometry by evening out inconsistencies and errors from previous drilling operations. The guide rods and precision cutting edges realign the hole and improve straightness.
Sizing and Work Hardening Holes
Forcing a reamer through a slightly undersized hole has a work hardening effect, compressing and cold working the inner surface. This increases hole size precision and improves surface finish.
In summary, reamers are indispensable for solving a variety of hole machining problems. Their unique cutting action and precision design make them an essential hole finishing tool for critical engineering applications.
Key Applications and Uses of Reamers
Reamers have become a staple tool for hole machining across many industries. Here are some of the most common applications and uses for these versatile cutting tools.
Aircraft and Aerospace Components
Reaming is extensively used in aircraft construction for opening up rivet holes and finishing hydraulic and fuel system bores. The aerospace industry relies on reamers for achieving the strict dimensional accuracies needed in turbine engine parts, landing gear, wings, and other critical assemblies.
Automotive Parts
Reamers fine tune holes for pistons, engine blocks, gears, valves, axles, bearings, and suspension components. They are indispensable for engine rebuilding and high performance automotive machine work.
Precision Instruments
- Surgical equipment
- Scientific instruments
- Measuring devices
- watches
From cranial drills to atomic clocks, reamers produce the smooth bores and precision fits needed in high-accuracy instruments.
Oil and Gas Industry
Heavy duty tapered reamers bore and finish holes for well casings, drill collars, pipelines, valves, and other oil field components where straightness and tolerance are critical.
Firearms
Reamers enhance accuracy and optimize fit in gun chambers, barrels, cylinders, bolts, and actions. They are essential for finish work on custom rifles and pistols.
Mold Making
The injection mold industry relies on reamers for finishing mold cavities and achieving highly polished surfaces. This allows molten plastic or metal to flow uniformly and release cleanly.
From tiny medical parts to massive oil pipelines, reamers play a key role in hole machining across virtually every manufacturing sector. Their unique cutting action makes them invaluable for high-precision bore finishing and sizing.
Choosing the Right Reamer Type and Size
With the wide variety of reamer types and sizes available, choosing the right one for your application requires careful consideration of the material, hole dimensions, surface finish, and production volume. Here are some key factors to help select the optimal reamer.
Hole Tolerance
The required hole tolerance dictates the type of reamer:
- Standard reamers for ±0.001" tolerance
- Precision reamers for ±0.0005" tolerance
- Micro-reamers for ±0.0001" or tighter tolerance
Material
Carbide reamers are best for hardened steels over 45 HRC. High speed steel is suitable for softer materials like aluminum, brass, mild steel, and some hardened steels.
Hole Size
Smaller holes under 1/4" diameter generally require special micro-reamers. Larger holes over 1" may need indexable or adjustable reamers.
Ream Allowance
The ream allowance, or amount the hole will be enlarged, determines the reamer size. A hole pre-drilled to 0.248" diameter would require a 1/4" reamer with 0.002" allowance per side.
Surface Finish
Flooded reamers perform best for finer finishes under 16 μin Ra, while standard reamers work for coarser finishes up to 125 μin Ra.
Features
Reamers with guide pads or replaceable pilots offer better straightness in deep holes. For blind holes, use bottoming or extended length reamers.
Production Volume
For high volume production, indexable or adjustable reamers may offset the higher initial cost. For lower quantities, solid carbide or high speed steel is more economical.
Consulting reamer selection charts and working closely with your tooling supplier will help identify the right style, material, tolerance grade, and features for your hole machining operation.
Reamer Materials: Pros and Cons
Choosing the right reamer material is crucial for optimizing tool life, hole precision, and cost-effectiveness. Here is a look at the pros and cons of common reamer materials.
High Speed Steel (HSS)
Pros:
- Good value for the price
- Easy to sharpen
- Handles interrupted cuts well
Cons:
- Lower heat resistance than carbide
- Not suitable for hardened steels
- Shorter tool life than carbide
Cobalt HSS
Pros:
- Superior hot hardness over HSS
- Higher wear resistance and tool life
Cons:
- More costly than standard HSS
- Still less heat resistant than carbide
Solid Carbide
Pros:
- Excellent wear resistance
- Great for hardened steels up to 65 HRC
- Maintains precision and tolerance
Cons:
- Brittle, prone to chipping and breakage
- Higher cost per tool
Ceramics
Pros:
- Extreme hardness and heat resistance
- Excellent wear resistance
- Good for high silicon aluminum alloys
Cons:
- Brittle with possibility of catastrophic failure
- Higher cost
- Lower toughness than carbide
Consider factors like workpiece material, hole tolerances, production runs, and operating parameters when selecting the optimal reamer material for your application.
Achieving Precision Holes and Fits with Reamers
When dimensional accuracy and hole precision are critical, reamers are often the best tool for the job. Here are some tips for using reamers to produce holes with exacting tolerances and quality surface finishes.
Use Rigid Setup
Reamers require a rigid machine setup using a mill, drill press, or lathe. The workpiece must be tightly secured. Use chucks, vises, jigs, and fixtures to minimize deflection and chatter.
Allow for Reamer Runout
The actual diameter of a reamer may be slightly oversized to account for runout. For example, to produce a 0.500" hole, a 0.497" or 0.498" reamer is preferable.
Drill Pilot Holes
Drill an accurately sized pilot hole before reaming. The hole should be 75-90% of the reamed diameter to provide optimal cutting action. Deeper holes may need an undersized pilot hole.
Use Proper Feed Rates
Ream at 50-150 SFM with light, steady pressure. Excessive feed rates cause chatter, poor surfaces, and reduced tool life.
Apply Cutting Fluids
Use generous amounts of cutting oil or coolant to improve finish, dissipate heat, and float chips from the hole.
Make Several Light Passes
Take several passes at final size rather than one heavy cut. This preconditions the hole and equalizes cutting forces.
Allow 5-10 Hole Diameters for Exit
Provide adequate space past the hole for the reamer to completely clear the workpiece before retracting.
Use Guide Bushings for Deep Holes
Guide bushings support the pilot end and prevent wiggle in deep holes. Alternatively, use reamers with replaceable pilots or pads.
Following these best practices will help achieve the precise hole sizes, excellent finishes, and tight tolerances possible with reamers.
Reamer Maintenance and Troubleshooting Tips
Proper reamer care and handling is essential for longevity and performance. Here are some key maintenance and troubleshooting tips.
Regular Sharpening
HSS and carbide reamers should be periodically sharpened to restore cutting edges. This also removes any built up edge or burring.
Proper Storage
Store reamers carefully in a clean, dry place to prevent damage. Wrap cutting edges with paper or use cases. Don't stack or mix with other tools.
Cleaning
Thoroughly clean reamers after each use. Remove chips, grit, and built up oils or coolants that can impede performance.
Lubrication
Apply light machine oil before storage. For extended storage, coat with rust preventive.
Inspection
Check reamers regularly for wear, chipping, cracks, or deviations from original dimensions. Replace as needed.
Troubleshooting Guide
- Oversize holes - resharpen, replace worn reamer
- Bell mouth holes - increase feed rate, use lighter cut
- Rough finish - resharpen, decrease feed, use cutting fluid
- Tapered holes - regrind reamer straight, improve rigidity
- Chatter marks - decrease feed, increase RPM, improve setup rigidity
- Short tool life - improper speeds/feeds, inadequate cooling
Taking steps to properly maintain your reamers will maximize their longevity while proper troubleshooting will get your hole sizing operations back on track.
Save on Reamers and Tools
Here are some tips for getting great deals on reamers, drill bits, cutting tools, and other workshop essentials:
- Check manufacturer websites for coupons and promotional offers
- Sign up for email newsletters from tool companies to receive discount codes
- Take advantage of seasonal sales events like Black Friday and holiday sales
- Check auction sites like eBay for discounted new and used tools
- Buy factory reconditioned or lightly used name brand tools
- Purchase tool sets for greater cost savings over individual pieces
- Compare prices across multiple retailers online
- Use a cash back portal when shopping online
With some savvy shopping techniques, you can build up your tool collection while staying within your budget. Let me know if you need any other workshop money saving tips!
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Discover The Benefits Of Using Reamers Tools For Your Cutting Needs
Reamers are rotary cutting tools used in metalworking to enlarge and size a hole by means of a multifluted cutting tool. Here are some benefits of using reamers tools for your cutting needs:
- Precision: Reamers are great for machining precision holes with a high degree of accuracy to leave smooth sides. They are designed to enlarge the size of a previously formed hole by a small amount but with a high degree of accuracy to leave smooth sides.
- Superior finish: Reamers should only be used to remove small amounts of material to ensure a superior finish to the hole.
- Predictable tool life: With reamers, a machinist can better predict tool life, leading to a more efficient and cost-effective machining process.
- Variety of uses: Reamers are available in a variety of shank styles that can be mounted into hand tools, chucks, collets, or other tool holders, and are used in a variety of portable or stationary machines such as drill presses, lathes, screw machines, milling machines, and more.
- Fast and accurate: When done correctly, reaming can be a fast and highly accurate operation that results in precision holes.
- Suitable for exotic alloys: Reaming is important when machining high-cost materials, such as Inconel and titanium, to ensure that the desired finish specification is met.
- No heavy cutting fluids required: Reaming doesn’t require heavy cutting fluids for optimal performance, so utilizing them can help reduce costs and environmental impact.
What Materials Can Be Reamed Using Reamers Tools?
Reamers are rotary cutting tools used in metalworking to enlarge and size a hole by means of a multifluted cutting tool. The materials that can be reamed using reamers tools include:
The material of the workpiece will determine which cutting fluid must be used to preserve the life of the reamer. Soluble oil can be used for aluminum, brass, stainless steel, and other materials. Reaming is important when machining high-cost materials, such as Inconel and titanium, to ensure that the desired finish specification is met.
