How much stock to leave for reaming

The pre-ream hole size affects characteristics in the reamed hole including hole finish, hole straightness, tool life, and cycle time. There are several ways in which the pre-ream hole size may be obtained some examples include investment casting, boring, line boring, rough reaming , and stamping. The most common way to obtain the pre-ream hole size is through drilling and the focus of this blog entry.

The appropriate amount of stock removal for carbide tipped and solid carbide reamers is generally 2 — 3 percent of the finished hole size. Carbide tipped and Solid Carbide Reamers need to have adequate stock to remove or they will rub in the hole and generate excessive heat.

This leads to premature tool wear and poor hole finishes. My preferred method for calculating the drill bit size is to take the desired finished hole diameter and multiply it by 0. So then, having explained more than you wanted to know, rule of thumb for reaming with a chucking reamer is to drill within fifteen thou, maximum, of finished size, then ream.

Reamers have limited flute volume, so they're quickly overwhelmed flutes get packed with chips if you leave much more. Also, new reamers have a limited cutting edge, which gets larger as the reamer is sharpened.

If you ream from a lathe tailstock, it's highly unlikely your reamer will be on center. That's the nature of most lathes--the tailstock is rarely dead concentric with the spindle, and that's key to good reaming.

If you intend to ream from your lathe, I've found that I get the best results when I grip the reamer by just a very short amount of the shank, so it's free to seek center at the cutting edge. That appears to be the best possible way to ream, unless you happen to have a floating holder. If you're reaming from a mill, or drill press, if you'll drill then ream without moving the part, the reamer should be reasonably concentric with the hole you've established, so it may perform quite nicely.

If you leave too much material for reaming, it's possible for the reamer to wing on a single flute, assuming it has minor damage. That can result in a bell-mouthed hole, oversized at the opening, and slowly drifting to nominal size as the reamer is piloted more and more by the resulting hole.

You can avoid that problem by leaving less material to ream. In such a case, you must balance the amount of remaining stock with the hole that results from drilling. Drilled holes often are not round, nor straight, so you must leave enough material to correct that problem. One then reams that hole. It may or may solve the problem, but it's one way to address the issue.

Luck with your reamer. I'm not a fan of those things, as I've seen more than my share of irregular holes, the result of reaming. Still, they're better than a twist drill! Oh, yeah! Related information Knowledge Knowledge.

New-tips-provide-new-possibilities News and Media. Chuck selection Knowledge. How to ream a hole. Stock removal The recommended stock removal in reaming operations is dependent on the application material and the surface finish of the pre-drilled hole.

Are you looking for tool recommendations? Find our cutting tools here. Through spindle coolant can be even more effective as it has a positive effect on chip control and chip breaking. Center Feed coolant aids chip clearing.

This is basically a function of the number of parts to be made and the hardness of the material being reamed. Even 20 parts should go carbide if you are reaming all but the very softest kinds of materials.

Get our latest blog posts delivered straight to your email inbox once a week for free. Lean Manufacturing Course. Free Calculators and References. Free Feed Rate Calculator. Back to Homepage. Shop All Our Products. This is Your Opportunity! Fix It! How to ream a hole? If you require more correction for straightness than that, boring may be a better approach. Reamer Hole Sizes Reamers are a fast way to finish a hole and very convenient relative to other precision approaches like boring.

There was recently some back and forth on CNCZone about reamer hole sizes, and I felt like it would be a good time to throw out that G-Wizard tells you the recommended guidelines for how far undersized to make your holes before reaming: G-Wizard says to make the hole 0.

Pre-ream Drill Size Chart The hole that will be reamed must first be drilled to an undersized diameter. Use a good quality chuck to hold the reamer. Use recommended cutting fluids for the reamer. Reaming an angled surface is not recommended if the angle is more than 5 degrees.

Uses the shortest tool overhang stickout possible. Reamer Holding Reamers are typically held by precision collets or hydraulic chucks. Reaming Twice If two much stock remains after drilling, it is possible to use 2 sizes of reamer to open up the hole.

Heat Treating Reamed Holes Heat Treatment will often shrink a reamed hole so do some experiments to determine exactly how oversized the hole should be before any shrinkage will bring it right down to spec and tolerances.

Interrupted Reaming A spiral flute reamer… If there are hole interruptions, such as a keyway or cross hole, you should use a spiral-flute reamer rather than a straight flute. Reamer Types and Selection Reamer Geometry and Flute Styles Reamers typically have one of the following flute styles: Straight: Best suited to non-chip forming materials.