# R8 Slitting Saw Arbor



## epanzella (Jan 3, 2022)

A friend gave me a box of slitting saws so I decided to make a 1 inch R8 arbor. I should have just made a 3/4" shank arbor instead of R8.  I started with an R8 by 1/2x20  store bought arbor and locktited a hunk of steel to the end. Then I had to make an R8 sleeve to hold it in the lathe holding the tolerance to .0005 in. Next I put the arbor in the sleeve with a bolt simulating a drawbar and went to work. Despite my best efforts the stacking of tolerances (I'm not that great anyway) caused about .002 wobble in the blade which was NG. I mounted the whole mess in my chambering fixture and managed to dial in to a few tenths but in truing the 1 inch bore I lost the great fit with the blades that I had originally. Anyhoo I ended up with just a few tenths wobble but now I have .001 runout at the saw teeth. It cuts OK but it has that same yang yang yang sound that I hear on youtube slitting saws. This is what I was trying to avoid. I also have to make an arbor for 1/2" saws but that will have a straight 3/4" shank so I can use my 5c collets in the lathe. The say you learn by your mistakes so how come I'm not a genius by now?


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## Just for fun (Jan 3, 2022)

"They say you learn by your mistakes so how come I'm not a genius by now?"

You and me both!


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## mmcmdl (Jan 3, 2022)

If the face is not perpendicular , could you not mount it in your mill , put a lathe bit in a vise and skim the face true ?


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## epanzella (Jan 3, 2022)

mmcmdl said:


> If the face is not perpendicular , could you not mount it in your mill , put a lathe bit in a vise and skim the face true ?


When I put it in my chambering fixture I did skim the face true but I also had to skim the bore true and that added some sideways runout. I used a factory R8 arbor to save time and it cost me way more time and some accuracy.


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## Lo-Fi (Jan 3, 2022)

If it's any consolation, I made a 3/4 straight shank holder in a single setup which indicates dead nuts on and my slitting saws still don't run true enough to cut completely evenly throughout the entire rotation. I've come to the conclusion it's just a fact of life with slitting saws, or at least the ones I can afford.

Nice work!


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## 682bear (Jan 3, 2022)

Lo-Fi said:


> If it's any consolation, I made a 3/4 straight shank holder in a single setup which indicates dead nuts on and my slitting saws still don't run true enough to cut completely evenly throughout the entire rotation. I've come to the conclusion it's just a fact of life with slitting saws, or at least the ones I can afford.
> 
> Nice work!



I have reached the same conclusion...

-Bear


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## aliva (Jan 4, 2022)

Every you tube video I've seen , the saw never runs true. I'm talking Fenner, Adam Booth Tom Lipton and many more. .001 run out seems to be normal.


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## brino (Jan 4, 2022)

Yup, you're in the same state as me and all my slitting saws and arbors.
Brian


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## mikey (Jan 4, 2022)

I have a few slitting saws that cut clean, without any odd sound, but most of them do. It only takes a tiny deviation of one or two teeth to make a saw do this, even if the arbor is dead nuts straight. It doesn't seem to affect the accuracy of the saw but if the arbor is not true then that does affect accuracy. Still, given that most slits or slots are not critical, this isn't that big a deal.


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## epanzella (Jan 30, 2022)

Just a follow up. In the first post I made an R8 arbor for 1 inch saws. Now I've made it's little brother from stainless. A 3/4" straight shank arbor for 1/2" saws. It was a lot easier to make it concentric as I used a collet in the lathe. They both use the same spanner wrench but I made a heavy cut with the big one and it self tightened. The spanner wouldn't loosen it so I had the mill some flats in the end.


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## ddickey (Jan 31, 2022)

A little radial run out on a saw doesn't really matter, can be the saw itself. 
Axial runout is what you don't want.


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