Tool Annular Cutter Accuracy

[Susquatch]

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?

 

[kstrauss]

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.

 

[Susquatch]

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.

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.......

 

[thestelster]

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.......

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

 

[quitereal]

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?
Next time I use one Ill measure the result for sure. (Not any time soon)

 

[Aarknoid]

thinking it might actually be 26mm cutter

 

[Aarknoid]

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

Beat me to it as I was typing

 

[Susquatch]

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.

 

[Ironman]

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

 

[Susquatch]

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

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.

 

[Susquatch]

How many flutes does the 1" have?

6 flutes

What does it measure?

0.998

Was it an ali express cutter?

No.

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

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

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

thinking it might actually be 26mm cutter

No, but again, a really good thought.

 

[PeterT]

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?

 

[phaxtris]

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

 

[Susquatch]

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

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]

Could it be one misaligned cutter tooth?