Types of Reamer Tools Used in Machining

What is a Reamer?

A reamer is a tool that makes holes better. When you need a hole that is just right, you use a reamer. First, you make a hole with a drill. Then, you use a reamer to make the hole the right size. A reamer helps make the hole smooth and the right size. 

Reamers are not for making new holes. They are for making holes that are already there better. They help make the hole the right size and make the inside of the hole very smooth.

Why Use Reamers?

Reamers help us in many ways:

• They make holes the right size
• They make the inside of holes very smooth
• They make holes round
• They help make parts fit together better
• They make holes that look good

Let’s look at all the types of reamers we can use!

Hand Reamers

Hand reamers are tools you use with your hands. You do not need a big machine to use them. You turn them with a handle or wrench.

When to use hand reamers:

• When you fix things in a small shop
• When you need to fix just one or two holes
• When you do not have big machines
• When you need to be very careful

Hand reamers are good for small jobs. They help you work slowly and carefully. 

Machine Reamers

Machine reamers work in big machines like ** machines. These machines spin the reamer very fast. You do not turn these reamers with your hands.

Machine reamers can have straight flutes or spiral flutes.

• Straight flutes go straight up and down
• Spiral flutes twist around the reamer

Spiral flutes help make the hole smoother. They also help get the little bits of metal out of the hole. 

Tapered Reamers

Tapered reamers are not the same size all the way down. They get bigger from the tip to the end. They help make holes that are not the same size all the way down.

Tapered reamers are good for:

• Valve seats in cars
• Pipe fittings
• Tools that need to fit just right

Shell Reamers

Shell reamers are hollow in the middle. They fit on a stick called an arbor. Shell reamers are good when you need to make big holes.

Why use shell reamers:

• They cost less than big solid reamers
• You can use the same arbor for many shell reamers
• They are good for big holes
• They save money

Expansion Reamers

Expansion reamers can change size a little bit. You can make them a little bigger or a little smaller. They can change about 0.15mm in size.

These reamers are good when:

• Holes get worn out and need to be fixed
• You need a size that is hard to find
• You need to make holes that are not a standard size

Adjustable Reamers

Adjustable reamers have blades that you can move. You can set them to many different sizes. They are very flexible.

You can use one adjustable reamer instead of buying many fixed-size reamers. This saves money in repair shops. 

Materials That Reamers Are Made From

Reamers are made from different metals. The kind of metal used depends on what the reamer will cut.

High-Speed Steel (HSS)

HSS reamers are good for:

• Most common jobs
• Cutting soft metals
• When you do not need the hardest tool
• When you want to save money

HSS reamers cost less. They are good for many jobs.

Carbide

Carbide reamers are very hard. They are good for:

• Cutting very hard metals
• Jobs that need to cut a lot of holes
• When the job needs to be done fast

Carbide reamers last 3-5 times longer than HSS when cutting hard steel. This helps save money over time. 

Cobalt

Cobalt reamers can handle hot jobs. They are good for:

• Cutting stainless steel
• Jobs where the tool gets very hot
• When HSS is not hard enough

Coatings

Some reamers have special coatings that make them work better:

• TiN coating makes reamers last longer
• TiCN coating helps cut hard metals

How to Pick the Right Reamer

Picking the right reamer is very important. The wrong reamer can make a bad hole.

Look at what you are cutting:

• For aluminum: Use HSS with smooth flutes
• For hardened steel: Use carbide or coated reamers

Look at how exact the hole needs to be:

• Normal jobs: ±0.025mm is OK
• Very exact jobs: ±0.005mm needs better reamers

Look at your machine:

• Hand tools need hand reamers
• CNC machines need machine reamers
• Strong machines can use bigger reamers

Look at how deep the hole is:

• Deep holes need reamers with ways for coolant to get in 

How to Use Reamers the Right Way

Using reamers the right way helps make good holes.

Setup Tips:

1. Drill a hole that is a little smaller than the size you want (0.1-0.5mm smaller)
2. Make sure the reamer is lined up straight
3. Use the right speed and feed
4. Use oil or coolant to keep the reamer cool

Speed and Feed Tips:

• Use half the speed you would use for drilling
• Use twice the feed rate you would use for drilling
• For HSS in steel, try 300 RPM 

Common Problems and Fixes

Sometimes things go wrong when using reamers. Here are some problems and how to fix them:

Good alignment reduces oversized holes by 80% in CNC reaming. 

Where Reamers Are Used

Reamers are used in many industries:

Cars

In car shops, reamers help make:

• Valve guide holes
• Bearing holes
• Parts that need to fit just right

Airplanes

In airplane shops, reamers help make:

• Hydraulic parts
• Holes for pipes and tubes
• Parts that must be very exact

Shell reamers cut costs by 20% for holes bigger than 25mm in aerospace parts. 

Medical

In medical tool shops, reamers help make:

• Very small holes in implants
• Parts that go in the body
• Tools that doctors use

Micro-reamers (smaller than 1mm) are used in 90% of medical implant screw holes. 

CNC Drilling and Reaming

When we use reamers in CNC machining, we can make very good holes. The computer helps the reamer work just right.

In CNC drilling first:

1. The machine drills a hole that is a little too small
2. Then the reamer makes the hole just right
3. The computer helps keep the speed and feed just right

Through-coolant reamers extend tool life by 50% when cutting titanium. 

Saving Money with the Right Reamers

Using the right reamer can save money:

• Adjustable reamers cut tool costs by 40% in car repair shops
• Carbide reamers last 3-5 times longer in hard metal 
• Shell reamers save 20% on big holes 
• Good setup reduces bad parts by 80% 

Questions People Ask

Summary

Reamers are very important tools that help make good holes. There are many types of reamers:

• Hand reamers for hand work
• Machine reamers for big machines
• Tapered reamers for holes that get bigger
• Shell reamers for big holes
• Expansion and adjustable reamers for different sizes

Pick the right reamer by looking at:

• What you are cutting
• How exact the hole needs to be
• What kind of machine you have

With the right reamer and the right way to use it, you can make very good holes that fit just right.

When you need holes that are just right, a reamer is the tool to use!

Learn More

Want to learn more about machines that can use reamers? Check out:

• CNC machining service
• 5 axis machining
• Precision CNC machining