runout in R8 chuck

[morrisman]

Hi

I have a R8 slitting saw chuck , one inch . Whenever I use the chuck in my 45 mill/drill , it has a runout . The saw makes contact with the workpiece with a rythmic chuff chuff sound as it cuts the metal on the same outer edge point of the saw - in other words it is not a constant cut but a interupted cut . I have tried different saws but that doesn't help . The R8 chuck appears to be OK with no visible runout evident . The saws have a tight fit on the chuck spindle with no sloppy play evident . I had to file the key down a tad so the saws will fit on . Mike

[Big Shed]

Mike, are you are sure it's not the saws? Most slitting saws seem to have some run out.

This was discussed at some length in this thread

http://www.woodworkforums.com/showthread.php?t=167935&highlight=slitting

[variant22]

I had an awful Soba slitting saw arbor. The type that had a tiny shank and held multiple sizes. The thing was scary at best and was completely unusable. I ditched it with the cheap saw blades and purchased a Tormach Slitting Saw arbor and some Osborn slitting saws from c-tool. Never looked back. It runs so true, no vibration, no uncertainty and cuts like butter. I run them in my 45 sized mill (the same as yours) and they are excellent. The first use was cutting some slots for machine guards in a single full depth pass..

304708

[PDW]

Hi

I have a R8 slitting saw chuck , one inch . Whenever I use the chuck in my 45 mill/drill , it has a runout . The saw makes contact with the workpiece with a rythmic chuff chuff sound as it cuts the metal on the same outer edge point of the saw - in other words it is not a constant cut but a interupted cut . I have tried different saws but that doesn't help . The R8 chuck appears to be OK with no visible runout evident . The saws have a tight fit on the chuck spindle with no sloppy play evident . I had to file the key down a tad so the saws will fit on . Mike

"No visible runout" is a meaningless concept. Stick a DTI on it and find out what the runout is (or isn't). Then you'll know.

Having said that, tolerance stacking always happens with slitting saws, side & face cutters etc etc. Unless you use something a lot more precise than a generic mill & arbor, in a temperature controlled environment, you'll always get some irregular cut as you're experiencing. Unless it's really extreme, don't worry about it. Next time you mount the cutter, it'll likely be in a slightly different spot and the runout will cause a different set of teeth to do most of the cutting.

PDW

[morrisman]

this is the type of chuck I have...mine came from cdco years ago

http://www.ebay.com.au/itm/R8-STUB-MILLING-ARBOR-1-1-4-SLITTING-SAWS-BRIDGEPORT-/370489830673?pt=UK_BOI_Metalworking_Milling_Welding_Metalworking_Supplies_ET&hash=item5642ea2d11

[PDW]

this is the type of chuck I have...mine came from cdco years ago

http://www.ebay.com.au/itm/R8-STUB-MILLING-ARBOR-1-1-4-SLITTING-SAWS-BRIDGEPORT-/370489830673?pt=UK_BOI_Metalworking_Milling_Welding_Metalworking_Supplies_ET&hash=item5642ea2d11

IMO that's way too long for running a slitting saw or milling cutter in a small mill. There's a lot of leverage there and the end is unsupported. If I were to use that arbor, I'd have the cutter as close to the spindle nose as it was possible to get.

My slitting saw arbor is about 1" longer than the R8 shank.

But - they all have some runout anyway. It's unavoidable, so as long as you're not getting chatter and it's cutting ok, I'd keep using it. Then I'd make a short one that fitted in an ER32 collet or something - if you were real lucky, you could rotate it and cancel out the tolerances. Or not, with my usual luck....

PDW

[morrisman]

Hi This is the slotting

BTW I bored out the cast iron bearings in this housing , with a 3/8" shank brazed carbide borer , mounted in my harold hall boring head . Well the thin shanked borer must have deflected as there was a .005" taper in the bearing bore . I re bored the hole using a HSS tip in a stout steel bar - this worked Ok , the bore is now level :2tsup:

[Stustoys]

Hi Mike,
One day I'm going to work out why Harold bothered to leave the center piece in there.

Stuart