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Tool Annular Cutter Accuracy

Tool
Susquatch

Susquatch

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With so many other projects on hold, today was the day I decided to make an adapter to attach 3/8 indicator holders to a 1" bar. I decided to use a piece of 1/2 plate mystery metal to make the clamp. I could have drilled it and bored it for a good fit, but a 1" annular cutter seemed like a faster better way to go.

Easy peasy, done in 2 minutes even accounting for setting up the Weldon Shank Arbour.

But.... The resulting hole is about a 32nd too big. I was shocked. I expected MUCH MUCH Better.

It's no big deal, it's a clamp. I can just yield it in my press to fit better. But it shatters my confidence in annular cutters.

Is this typical? I've never noticed such a difference before.

What do you guys experience?
 
Was the stock very well clamped? Is the hole round? I've had problems with the stock wiggling and making an oval and oversize hole.
 
kstrauss said:
Was the stock very well clamped? Is the hole round? I've had problems with the stock wiggling and making an oval and oversize hole.
Click to expand...

Torqued right down tight on my Gerardi vise. Nothing moved. Not oval either - or even rough! I'm thinking the 1" annular cutter is really 1-1/32.......
 
How many flutes does the 1" have? What does it measure? I have an unused 13/16 with an even number of flutes that measures .811
Was it an ali express cutter? :P
Next time I use one Ill measure the result for sure. (Not any time soon)
 
I just measured it at 0.998. It has 6 flutes. They are VERY aggressive.

I will confess using medium pressure. Not a ton, but enough to keep it biting. I don't like work hardening what I cut.

The hole is clean as a whistle - much cleaner than a drill would do. Prolly similar to what a boring bar would do.
 
John, has this cutter been re-sharpened? I have drill 1-3/16 a few times with Accusize cutters and the hole was a precision fit.
Ive noticed my 3/4 after sharpening made looser hole, never measured it
 
Ironman said:
John, has this cutter been re-sharpened? I have drill 1-3/16 a few times with Accusize cutters and the hole was a precision fit.
Ive noticed my 3/4 after sharpening made looser hole, never measured it
Click to expand...

This one has only been used once before (that I remember anyway). I bought it new for another job. I don't recall noticing an oversize hole. It most certainly has never been sharpened as I don't have the ability to do that. It cut fantastic - just a tad big.
 
quitereal said:
How many flutes does the 1" have?
Click to expand...

6 flutes

quitereal said:
What does it measure?
Click to expand...

0.998

quitereal said:
Was it an ali express cutter?
Click to expand...

No.

thestelster said:
Oh...you mean 26mm!! Is your cutter made in an exotic foreign country where Imperial dimensions are merely a footnote?
Click to expand...

No, it's clearly marked 1" and it measures 0.998

But that's a really good thought. I wouldn't have been surprised.

Aarknoid said:
thinking it might actually be 26mm cutter
Click to expand...

No, but again, a really good thought.
 
Mine are consistently accurate, couple thou within nominal. I have some TMX & tried some from Accuzize with similar results. 1/32 ~ 0.032" is way more than I would expect.
I have heard of mislabelled or unlabelled sets from China where they think they are doing you a favour calling a 25mm = 1". But of you are measuring 0.998" cutter OD & get 1.032" ID hole something is funky.
Long shot but have you put a DTI on the cutter body once in the Weldon holder & mounted in mill? It should be bang on but maybe your cutter shank is not concentric with cutter body or tool holder bore not concentric with spindle so its running eccentric? Maybe a Monday dud?
 
I use annular cutters a lot, 1/32 is a lot out

I wouldn't expect a 1" cutter to actually make a 1" hole, maybe .010 over at most, but not .032 over. bad holder, bad cutter (body to shank), bad sharpening, it's not a finish dimension type of tool like a reamer, but it shouldn't be that much out (given a good tool) without a pile of slop somewhere (mag drills tend to develope a lot of slop in the Gibbs), or a bad holder
 
PeterT said:
Mine are consistently accurate, couple thou within nominal. I have some TMX & tried some from Accuzize with similar results. 1/32 ~ 0.032" is way more than I would expect.
I have heard of mislabelled or unlabelled sets from China where they think they are doing you a favour calling a 25mm = 1". But of you are measuring 0.998" cutter OD & get 1.032" ID hole something is funky.
Long shot but have you put a DTI on the cutter body once in the Weldon holder & mounted in mill? It should be bang on but maybe your cutter shank is not concentric with cutter body or tool holder bore not concentric with spindle so its running eccentric? Maybe a Monday dud?
Click to expand...

phaxtris said:
I use annular cutters a lot, 1/32 is a lot out

I wouldn't expect a 1" cutter to actually make a 1" hole, maybe .010 over at most, but not .032 over. bad holder, bad cutter (body to shank), bad sharpening, it's not a finish dimension type of tool like a reamer, but it shouldn't be that much out (given a good tool) without a pile of slop somewhere (mag drills tend to develope a lot of slop in the Gibbs), or a bad holder
Click to expand...

I had already disassembled everything when I discovered the overesize hole.

The 32nd is just an eyeball measurement. Looked like half a 16th.

I am embarrassed to admit that I didn't notice any wobble nor measure any.

I will put it all back together later today and measure it.

Given all the good experience others have had with annular cutters, it makes sense to me that it must be wobbling. I'm also a little suspicious of the moderate pressure I applied.

Last, but not least, I noticed some markings on the arbour R8 taper. I remove the index pin on my quill. I doubt that's an issue but I'll dig into that a bit more too.

I always wipe down my tapers, but I don't always wipe the inside taper.

Bottom line - others have not had any instances of oversized holes, but I did. So the issue is not annular cutters but more likely some other issue that must be chased down.
 
FatherWes said:
Could it be one misaligned cutter tooth?
Click to expand...

I looked very closely at that. There is in fact one tooth that is "different". It's not out such that it would cut bigger. It's just a different shape. The cutting edge is a bit wider than the others. Hard to explain - maybe I'll post a photo if I can capture the difference.
 
Hard to take a good photo of this.

20241114_151144.jpg

The cutter has three outer cutting edges and three inner cutting edges. One the outer cutters has a circular edge in it while the other two look more like J's.

I can't see any other difference. However, the arbour does have about 1.5 thou runout at the nose and 1 thou at the spindle. I cannot measure runout at the end of the cutter, but assuming it's linear, it might be 5 thou total. Not +/- 5. More like +/- 2.5. Based on a cutter diameter of 0.998, that might result in a hole that was 1.003. But the reality is more like 1.030.
 
IIRC from when I was learning about sharpening them, there is typically 2 different tooth profiles on a singular annular cutter, the profiles alternate every tooth, I don't remember the reasoning, chip evacuation? More efficient cutting? But I recall not ever tooth had the exact same geometry
 
I have annular cutters in 5 sizes. In steel, they all cut about .003-.004 oversize, depending on the cut. I use soluable oil coolant, hand sprayed on. Without the coolant, the hole is larger, but I can't remember how much bigger. (that work piece is long gone). My cutters are all about .001-.002 above the marked nominal dimension (I have Imperial cutters)

I can guess (only a guess, mind you) that stuck swarf might be offsetting the cutter causing a few outer teeth to be cutting a wider path.
 
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