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1.5" Round Nose Bit - Tearout Problem

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Forum topic by Keith Kelly posted 02-08-2015 07:43 AM 1036 views 0 times favorited 11 replies Add to Favorites Watch
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Keith Kelly

223 posts in 1131 days


02-08-2015 07:43 AM

I’m making some black walnut coffee scoops for friends and family.

I mistakenly thought that a 1.5” round nose router bit would make this process a lot easier. I splurged and got a Whiteside for +$50. For the life of me, I can’t avoid tearout when the bit starts making full contact with the wood. Tearout happens on the end grains.

Here’s what I’ve tried:
  • Drill press on different speeds
  • Plunge router clamped to workpiece @ full speed (mistake)
  • Stronger plunge router (Hitachi 3 1/4 hp) clamped to workpiece with external variable speed control, different speed settings
  • Using 3 forstner bits (1.5”, 1”, .5”) in sequence to hog out the hole in steps so the router can have an easy job
Incomplete thoughts:
  • Maybe when I tried it on the full-speed plunge router, maybe I heated/dulled the bit? I think I recall seeing burn marks during one light plunge, but nothing excessive and the bit looks fine.
  • Maybe I should try my other Hitachi 3 1/4 hp plunge router that has the built in speed control, and therefore probably keeps the lower speed more consistent. (I didn’t start with the Hitachi routers because they are both mounted in my router table, and weren’t as convenient)

Any advice would be very much appreciated.

-- Keith - Bolivar, Missouri, http://www.SquareOneWoodworks.com


11 replies so far

View Woodendeavor's profile

Woodendeavor

276 posts in 2074 days


#1 posted 02-08-2015 12:11 PM

Can you post a picture of what they look like?

View ohtimberwolf's profile

ohtimberwolf

636 posts in 1820 days


#2 posted 02-08-2015 10:18 PM

Can you clamp or tape a piece of wood on the item to let your bit/bits cut through just as you would on any other cut that stops tear out? With a good hard wood you may be able to reuse the sacrifice. Just a thought.

-- Just a barn cat, now gone to cat heaven.

View Keith Kelly's profile

Keith Kelly

223 posts in 1131 days


#3 posted 02-08-2015 10:35 PM

Woodendeavor – here are pics.

Timberwolf – I may have used the wrong terminology. Here are photos that should help explain. I’m not cutting through the board. See below.

(I can certainly do more tests, but direction from you guys might save me some hassle)

First Cut – Delta drill press set to 3100rpm. Chatter. I don’t suspect this is a problem with the blade, but probably a less than perfect drill press chuck. After making this cut, both bit blades showed signs that they were cutting the wood.

Second cut – 2 1/4 hp plunge router on full speed. Router was clamped securely to workpiece.

Third cut – 3 1/4 hp plunge router w/ ext speed control, tried at various speeds. I did not observe a difference in low vs high speeds. However, perhaps the low speeds had some issues due to the router losing speed since the speed control is external w/ no speed matching. Router was clamped very, very, very, very securely to workpiece.

For the fourth cut (not pictured) I took out some of the wood using a forstner bit ahead of time. However, there were no observable differences.

Note: I’m pushing the router down extremely, extremely, extremely slow and with very minimal pressure (any less pressure, and the bit doesn’t cut.

-- Keith - Bolivar, Missouri, http://www.SquareOneWoodworks.com

View ohtimberwolf's profile

ohtimberwolf

636 posts in 1820 days


#4 posted 02-08-2015 10:42 PM

What is the end grain like? Is it tight or are you seeing the tubular nature of the wood. I hate to think that a $50 bit is dull. Try it on some cherry or such and see if it does the same thing. If so they need to replace your bit in my opinion (which is just worth that).

-- Just a barn cat, now gone to cat heaven.

View Keith Kelly's profile

Keith Kelly

223 posts in 1131 days


#5 posted 02-08-2015 10:51 PM

Good idea about trying a different species of wood. On that note, I realize I may have told you the wrong species of what this is. I purchased it from an amish mill who said “it smelled like walnut when we cut it, but the tree didn’t look like walnut.” After research and comparing against known Black Walnut in my shop, I’ve come to the conclusion that some of this is probably Claro Walnut (though I live in Missouri, which is weird). If you think otherwise let me know, but I say this in case Claro has a different workability. (pic 1 is likely Black Walnut, and pics 2-3 are the potentially Claro Walnut from the mill.)

End grain

-- Keith - Bolivar, Missouri, http://www.SquareOneWoodworks.com

View firefighterontheside's profile

firefighterontheside

13529 posts in 1324 days


#6 posted 02-08-2015 11:05 PM

My experience with a bowl bit is that they are not very good at plunging unless you have one where the two cutters bypass each other. I would think your best hope for making this work is to have your speed set about 15,000 rpm( looked at a chart) predrill as you did as deep as you can such that the router bit bit eventually removes the pilot Mark from the Forstner bit.

-- Bill M. "People change, walnut doesn't" by Gene.

View Keith Kelly's profile

Keith Kelly

223 posts in 1131 days


#7 posted 02-10-2015 03:05 AM

Alrighty, I’m fairly convinced there’s an issue with the bit. Here’s a test on some Sassafras with a variable speed plunge router at 16,000 rpm (according to the lookup chart in the router manual) which is the speed Whiteside says should be used for this size of bit.

I’ve worked with Sassafras a significant amount during a recent project, and it cuts easy. However, there were significant tearout issues:

ouch

-- Keith - Bolivar, Missouri, http://www.SquareOneWoodworks.com

View Rick Bailey's profile

Rick Bailey

247 posts in 830 days


#8 posted 02-10-2015 03:15 AM

Looks like a dull bit to me.
Try this, score a line around the hole first with a sharp knife, about a 1/8 if you can.
You want to cut those fibers at the top of the cut before you drop the router down.
I do this when working with wenge.
Rick

-- I'll bulid your dream,you tear it down.

View Tony_S's profile

Tony_S

608 posts in 2551 days


#9 posted 02-10-2015 11:10 AM

I’d bet the issue is the collet, and not the router bit. I’ve bought close to 100 bit’s from whiteside in the last 2-3 years and haven’t had any QC issues yet. It’s always possible the bit is defective, but not likely.

Bigger, heavier bits are a lot more sensitive to collet runout than smaller bits are. The collet might be dirty or damaged, or may just have been crap right from the factory and you hadn’t noticed it before.

Unclamp the router and hold it up freehand(not on its base) and turn it on. Does it vibrate at all?
If it does, clean the collet really well and try it again. If there’s no improvement, try a new collet.
Last resort, call Whiteside.

-- It is the mark of an educated mind to be able to entertain a thought without accepting it. Aristotle

View Dan Krager's profile

Dan Krager

3271 posts in 1702 days


#10 posted 02-10-2015 09:57 PM

You might be fighting more than one issue. Consider that the bit is is not surgically sharp AND runout is excessive. It is possible that the bit blades are not cutting the same amount on each side>one blade is a few 10/1000” farther from center than the other.
If none of the above (unlikely), try cutting down to say 1/16” of final depth. Then soak the pocket with just about all the mineral oil it will soak up, probably lots. Let it sit for a few minutes, wipe it clean and then finish your cut. You might be surprised at the result.
DanK

-- Dan Krager, Olney IL http://www.kragerwoodworking.weebly.com There are three types of people...those who are good at math and those who aren't.

View Keith Kelly's profile

Keith Kelly

223 posts in 1131 days


#11 posted 02-10-2015 10:12 PM

Thanks for the tips. I ended up drilling a bunch of holes in 1/4” MDF with a Forstner bit to create a template. Then I clamped that to my workpiece and routed a bunch of scoops using a bowl & tray template bit w/ bearing.

In a nutshell, I gave up on this bit. I contacted the seller and it’s going back. I’ve had great luck with Whiteside in the past, so I suspect this is either user error or a rare case of bad luck.

Side note: there was no vibrating, but that’s a good call and I didn’t think to debug that before.

-- Keith - Bolivar, Missouri, http://www.SquareOneWoodworks.com

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