Coloring upcut spiral bits with permanent markers

[Phil Thien]

I have my little mortising jig which I get quite a bit of use from. Here, this one:

cgallery.com/jpthien/mj.htm

With this jig I have been using spiral upcut bits.

One thing that has ALWAYS bothered me was how spiral upcut bits have a tendency to slip in the collet. You really have to crank the collet down quite hard, and be careful not to take too much of a bite, and check from time to time to make sure the bit is staying put.

Last week I thought I'd order a single-flute solid carbide straight plunging bit. I found this one, on Amazon:

http://www.amazon.com/Freud-03-140-4-Inch-Diameter-Straight/dp/B00004T7AX/ref=sr_1_1?ie=UTF8&qid=1354456269&sr=8-1&keywords=freud+single+flute

Made by Freud, it should be a pretty good bit.

I was surprised when I used it to make my first mortise, though, that it cuts a slot that is only about .23" wide. I can see a reason for at some of the difference, there is a step in the grinding of the bit.

Now, I've never used a single-flute solid-carbide bit before. I have no idea if they cannot actually make a bit where the cutting width equals the shank diameter. It does seem like it would be a challenge if you think about the geometry of producing a bit with a sharp cutting edge equal to the O.D. OTOH, they seem to be able to do this with spiral bits.

I actually purchased two of these Freud straight single-flute bits, in different lengths. One cuts a slightly smaller path than the other, but they're both undersized.

And it wouldn't matter much, I'm cutting mortises. I can cut the tenon stock to match, no big-deal. But the cut made by the single-flute bits is a little rough. Nowhere near as nice as the spiral bit.

So I'm back to researching the slippage of spiral bits. Looking at it from many angles, doing google searches for slipping end mills, etc.

One guys says that in the machine shop, they used a permanent marker to color the shank of the end mills, to prevent slipping. More googling on permanent markers on end mills and upcut bits really turns up nothing. A few posts from people saying to mark the bit's shank once it is mounted so you can check if it is slipping. But not using the marker to PREVENT slipping.

But when I was in the shop this morning, I took a permanent marker and colored the shank of an upcut bit, let it dry, and noticed the dry marker has left a slight texture to the shank of the bit. Like 50,000-grit sandpaper. Absolutely more "grippy" than without the marker.

I don't have any long-term experience yet, but I'm encouraged so far. I still plan on cranking the collet down pretty hard. But hope this "trick" provides a little insurance against slipping spiral bits.

I'll report back after some long-term use.

Your mileage may vary greatly.

[pat warner]

Router collets are designed for ordinary use with small cutters.
There is nothing holding the tool shank but friction.
Routers are simple miniaturizations of shapers, CNC machinery and mills, not substitutes.
(These machines have collets that hold their tools.)
It's a miracle routers work as well as they do.
The perception is that they should work like production machinery.
They don't.
Keep them inside of their ordinary working and tool envelopes and they perform well.
Big, long, large diameter, & spiral (up or down) cutters, are all cutters that may slip in the collet no matter how hard you pinch them down.

[Phil Thien]

Router collets are designed for ordinary use with small cutters.
There is nothing holding the tool shank but friction.
Routers are simple miniaturizations of shapers, CNC machinery and mills, not substitutes.
(These machines have collets that hold their tools.)
It's a miracle routers work as well as they do.
The perception is that they should work like production machinery.
They don't.
Keep them inside of their ordinary working and tool envelopes and they perform well.
Big, long, large diameter, & spiral (up or down) cutters, are all cutters that may slip in the collet no matter how hard you pinch them down.

Agree 100%.

I'm just hoping the magic marker gives me a slight improvement.

[Chris Fournier]

Router collets are designed for ordinary use with small cutters.
There is nothing holding the tool shank but friction.
Routers are simple miniaturizations of shapers, CNC machinery and mills, not substitutes.
(These machines have collets that hold their tools.)
It's a miracle routers work as well as they do.
The perception is that they should work like production machinery.
They don't.
Keep them inside of their ordinary working and tool envelopes and they perform well.
Big, long, large diameter, & spiral (up or down) cutters, are all cutters that may slip in the collet no matter how hard you pinch them down.

I wouldn't say that a router is a miniaturization of a shaper exactly as the shaper utilizes a spindle to hold cutters, not a collet. Truth is that the shaper spindle uses friction to hold a cutter head on the spindle. Friction is holding things all over the place! This difference certainly shouldn't hold the router back when it comes to using simple straight cutters for mortising, slotting, grooving etc.. In fact many metal milling machines be they manual or CNC utilise a split collet system to hold cutters using frcition as you point out. 5C, R8, ER are but three of many split collet options used on metal mills for decades with great success.

Make sure that the cutter and collet are free of oil, debris and galling, this will ensure that you'll be getting the best performance that you can out of the system. There's no doubt that you can likely stuff too much cutter in your router and get it to slip, experience or common sense must be your guide in these instances.

[Phil Thien]

In fact many metal milling machines be they manual or CNC utilise a split collet system to hold cutters using frcition as you point out. 5C, R8, ER are but three of many split collet options used on metal mills for decades with great success.



Well in my research there are plenty of machinists complaining about end mills slipping in collets. In that world they have end mill holders which may have a bit more runout (compared to a collet), but they hold the cutter much more securely.

I think Pat's point about the shaper is worthwhile. I took him to mean that the many people use the router for tasks that would have historically been performed by the shaper. But the means of securing the tooling on the shaper is a magnitude of order better than a split collet. You simply cannot compare the grip of tooling on a shaft snugged to a flange by a nut, to tooling being gripped by a collet. The spindle/nut wins every time.

[Joe Angrisani]

.....I was surprised when I used it to make my first mortise, though, that it cuts a slot that is only about .23" wide. I can see a reason for at some of the difference, there is a step in the grinding of the bit.

Now, I've never used a single-flute solid-carbide bit before. I have no idea if they cannot actually make a bit where the cutting width equals the shank diameter.....

Can you use a 1/2" shank bit? Slight collet variences aside, a 1/2" shank has about twice the clamping area of a 1/4" shank.

[Phil Thien]

Can you use a 1/2" shank bit? Slight collet variences aside, a 1/2" shank has about twice the clamping area of a 1/4" shank.

My mortising jig is fit to the little Dewalt DW611PK, which only accepts 1/4" bits.

[Chris Fournier]

Well in my research there are plenty of machinists complaining about end mills slipping in collets. In that world they have end mill holders which may have a bit more runout (compared to a collet), but they hold the cutter much more securely.

I think Pat's point about the shaper is worthwhile. I took him to mean that the many people use the router for tasks that would have historically been performed by the shaper. But the means of securing the tooling on the shaper is a magnitude of order better than a split collet. You simply cannot compare the grip of tooling on a shaft snugged to a flange by a nut, to tooling being gripped by a collet. The spindle/nut wins every time.

First of all most of the daring router bits these days are profile bits, these bits do not have significant up or down forces rather they have radial forces. It would be absurd to to think that the manufacturers are providing the marketplace with dangerous bits that relieve themselves of a collets grip. Quite frankly if you really think that the shaper's spindle/nut is king then you would be living in a world of the horizontal mill - a dinosaur (I own one and it is a treat but nowhere near as versatile as the vertical mill which I also own). Surely the horizontal mill is a shaper tilted 90 degrees. These machines are all but relegated to history. The spindle/nut is a woodworking phenom, the demanding world of metal has left this format behind and embraced the split collet. The split collet has concentricity that can't be beat.

I use a spiral bit to profile 2" of wood in my pin router on a regular basis with no troubles. I believe that my opinion is valid. Experience and common sense are key.

What kind of chuck do the Europeans provide on thieir slot mortisers? Machines which excel/require up cut bits. A wescott chuck - primitive to say the least - two contact surfaces with the cutter but I've never had a cutter move in 15 years.

[pat warner]

" It would be absurd to to think that the manufacturers are providing the marketplace with dangerous bits that relieve themselves of a collets grip."
************************************************** *
Just for the record there are dozens of cutters stuck in the work.
Ogees, slottlers, glue jointers, beaders, fluters, rounding under cutters, tee molders, dovetail bits, etc. They're all stuck/trapped in the work.
The dovetails, spiral and on-shear cutters have axial vectors pulling them from the collet, the others do not unless you tip the router.
And who has not not tipped a router?
Make a turn, bobble the tool, slip off the templet and you're tugging on the collet.
On the router table if the stock is cuppped, bowed or crooked, the fence cupped or the table mishappen, you will be pulling trapped cutters from their collets. Most dislodged cutters, or spontaneous depth changes result from these phenomena, not necessarily from an under-torqued collet net. Altho that does happen.
Were the cutters designed to tug on the collet? Not intentionally but from a practical point of view, it is no problem to dislodge a cutter from its collet. Big cutters in big machines with spot ground shank flats, threads etc, will stay in the machines. They may break but they ain't easily slipping in the collets or chucks. Not lookin' for a fight, just making it a little safer for some folks who think the router might be an Induma in disguise.

[Phil Thien]

First of all most of the daring router bits these days are profile bits, these bits do not have significant up or down forces rather they have radial forces. It would be absurd to to think that the manufacturers are providing the marketplace with dangerous bits that relieve themselves of a collets grip. Quite frankly if you really think that the shaper's spindle/nut is king then you would be living in a world of the horizontal mill - a dinosaur (I own one and it is a treat but nowhere near as versatile as the vertical mill which I also own). Surely the horizontal mill is a shaper tilted 90 degrees. These machines are all but relegated to history. The spindle/nut is a woodworking phenom, the demanding world of metal has left this format behind and embraced the split collet. The split collet has concentricity that can't be beat.

I use a spiral bit to profile 2" of wood in my pin router on a regular basis with no troubles. I believe that my opinion is valid. Experience and common sense are key.

What kind of chuck do the Europeans provide on thieir slot mortisers? Machines which excel/require up cut bits. A wescott chuck - primitive to say the least - two contact surfaces with the cutter but I've never had a cutter move in 15 years.

So just to be clear, only inexperienced machinists with no common sense use end mill holders?

All experienced machinists with common sense use only collets?

Collets never slip, so there is no reason to forsake the concentricity of a collet for the tighter grip of an end mill holder?

Am I correct?

[Chris Fournier]

So just to be clear, only inexperienced machinists with no common sense use end mill holders?

All experienced machinists with common sense use only collets?

Collets never slip, so there is no reason to forsake the concentricity of a collet for the tighter grip of an end mill holder?

Am I correct?

I never said any of that. Keep it factual and on point and we have a discussion. You are lashing out at what? You are certainly not furthering any useful or informative discourse at this point. Refute my post with facts not bombast and I'll be happy to defend decades of machining wisdom and practice.

[Phil Thien]

I never said any of that. Keep it factual and on point and we have a discussion. You are lashing out at what? You are certainly not furthering any useful or informative discourse at this point. Refute my post with facts not bombast and I'll be happy to defend decades of machining wisdom and practice.

I'm not lashing out, Chris, just asking questions.

So I now take it you agree that there are instances where machinists would use end mill holders because a bit may slip in a split collet?

Hopefully you would agree then that it follows that a bit slipping in a collet isn't necessarily evidence of a lack of "experience" or "common sense," as you mentioned in your post #4 and again in #8? That if a tool only accommodates a split collet, and bits sometimes slip in split collets, well...

Remember, I showed up here to pass on a tip (from a machinist) to prevent small D shafts spinning at high-RPM's from slipping in cheap, manufacturer-supplied split collets. If I was allowed to link to other woodworking forums, I'd have simply done that.

You are the one to start tossing around words like "experience" and "common sense," not me.

[Mikail Khan]

Back to the topic. Could it be that the alcohol from the marker and the felt tip is removing oils from he shank of the bit?

MK

[Phil Thien]

Back to the topic. Could it be that the alcohol from the marker and the felt tip is removing oils from he shank of the bit?

MK

I suspect that accounts for at least some of it. There is a Wikipedia article on permanent markers here:

http://en.wikipedia.org/wiki/Permanent_marker

I don't think the solvent accounts for all of it, though. I did a little experiment where I took a HSS knife and cleaned an area with lacquer thinner. After the thinner flashed off, I then colored part of the area with permanent marker, and the other half was left clean. The area with the permanent marker had a different feel to it.

[Chris Fournier]

I'll say this much for the marker, it makes it easy at a glance to know that you're dealing with an upcut bit. If that's all it does that's not a bad thing. Solid collets and Weldon shank bits are pretty old school and there's really not application for them in woodworking given the machines produced today.

[Keith Christopher]

"and be careful not to take too much of a bite,"

How big of a bite before they start slipping ? I was going to ask if you were hogging out too much material too quickly.