Thread: Pressure, Pull, and tool chatter

For those of you who have never cut metal (likely happens w/ wood also), tool chatter is a flexing and release of tension of a tool's cutting surface on the material to be cut. With power tools, the flex/release cycle usually grows more intense, leaving a rippled finished on the material cut. It's often a sign that too big a cut is being attempted w/ a light tool.

For those of you w/ course beards, doesn't this sound alot like a 5/8 full or extra hollow with the entire length of the blade engaged when it runs into a course section of stubble? The blade screams 'ALL STOP', and your adrenalin rightly convinces you that if you force it, you will be sporting another mouth.

This led me to the heavier grinds, which for me are much more forgiving. When possible, that's what you'd want when cutting metal also. More beef, less ability to make it flex or vibrate. It also will do greater damage if you get foolish, but generally it works. While I can plow on w/ a wedge or 1/4 hollow, it still acts like the heavy tool - fabulous for taking away the vast majority of the stubble, but at some point, you'll be touching up with finishing strokes that are using a small portion of the blade - a smaller, lighter cut. Just like finishing cuts on metal or wood.

So I learned to work w/ the small hollow and get the same result, but it took more time & care, mostly because the heavy stubble forces me to start taking the smaller cuts way earlier to avoid the flex & fear. To use the example above, the heavy stubble begins about 1" above jawline. The jawline is at an angle to a north/south cut. With the full hollow, I have to keep the edge fully horizontal or even angled further away from parallel to the jawline, so it never engages the entire blade length w/ the heavy cutting. The heavy grinds remain composed and I engage the full length of cutting edge by stroking parallel to the jawline & just run the whole blade length over the line and down the neck. All this does is complete a first pass in less time. XTG & ATG seem to take the same or similar amount of time with either a hollow or the heavy grind. Like metal or wood, the majority of the time is spent on the finishing cuts.

I know GSsixgunner has done more than a little time on a lathe (probably a vertical mill also), and probably many others. Do you guys think the wood/metal comparison is valid? Helpful? It helped me sort out why the heavy grinds were more comfortable and saved time. The noob that has heavy stubble is going to run into this condition. I'd like to make that obstacle easier for others.

This comes up a lot and sorry but I don't agree with you. You don't need to suit the razor to your face. You can get just as great and comfortable a shave with a double hollow as with a wedge no matter how tough your beard. If you can't it's either you or your razor.

My example I always site is the fact professional barbers back in the day should have had an arsenal of different sizes and grinds to shave their customers if that argument was valid but they didn't. Most barbers had a few working razors and they were hollow grinds (full hollows) and either 5/8s or 6/8s and they shaved everyone who came into the shop with those and everyone got a BBS shave.

I know squat about power tools though.

IME chatter happens when you present the tool in an inappropriate manner. This is true for metal, wood and whiskers. The chatter is the tool telling you that you are doing something wrong. A common mistake for learning wood turners is to hold the tool tighter or push down harder on the tool rest. The proper thing to do is to utilize this feedback and respond accordingly. if a lathe bit is hitting above centerline and therefore chattering you wouldn't just get a bigger shafted bit in there; you would reposition the bit in the proper position for that particular cut. I feel that the same applies for a razor. if its chattering on your face I would take the time to figure out what technique I am missing to fix the problem rather than find a different tool.
I have to admit though that I found days when I didn't want to deal with the technique so I found a razor that I knew better.

-G

Originally Posted by deighaingeal

IME chatter happens when you present the tool in an inappropriate manner. This is true for metal, wood and whiskers. The chatter is the tool telling you that you are doing something wrong. A common mistake for learning wood turners is to hold the tool tighter or push down harder on the tool rest. The proper thing to do is to utilize this feedback and respond accordingly. if a lathe bit is hitting above centerline and therefore chattering you wouldn't just get a bigger shafted bit in there; you would reposition the bit in the proper position for that particular cut. I feel that the same applies for a razor. if its chattering on your face I would take the time to figure out what technique I am missing to fix the problem rather than find a different tool.
I have to admit though that I found days when I didn't want to deal with the technique so I found a razor that I knew better.

-G

As a noob, I have to agree. Chatter in my case is usually a result of improper blade angle, poor lather or both. However, I find a 6/8 more forgiving as well due to the additional mass.

I get blade chatter sometimes on top of my head. It always means one of two things: my lather is too dry or my blade is too dull.
I usually think of "chatter" more like windshield wipers on a dry windshield. I am not sure how that works with the tool analogy. I would think wiper blades of a heavier construction would still chatter, but probably less noticeably. Perhaps that is what happens with the heavier grinds of razors? IOW the problem hasn't been corrected, but the symptom is lessened by using a heavier grind.
That's all hypothetical, of course.

I have to agree with the rest that it's with edge or the technique. Since you are getting 'acceptable' shaves off the heavier grinds your technique is probably good enough. I'd say get the hollows re-honed to a better edge or give them a few licks with chrome oxide or diamond paste/spray on a cloth strop, balsa or hard felt. Less is more with the pastes/spray. You can always give it a few more licks if needed.

Same goes with metal cutting. Either the tool or wheel isn't sharp enough, something is moving where it shouldn't or speeds and feeds are off.

Originally Posted by pinklather

For those of you w/ course beards, doesn't this sound alot like a 5/8 full or extra hollow with the entire length of the blade engaged when it runs into a course section of stubble? The blade screams 'ALL STOP', and your adrenalin rightly convinces you that if you force it, you will be sporting another mouth.

At this point you should drop your angle to virtually flat. If the blade is properly honed & of good quality ie the edge holds up for the full shave, the grind is irrelevant.
I'll agree a stiff grind may be easier to use for beginners but at some point you have to stop being a beginner & get your technique down.

Originally Posted by onimaru55

I'll agree a stiff grind may be easier to use for beginners but at some point you have to stop being a beginner & get your technique down.

Yep..............

Gents, thank you.

I have had trouble w/ lather getting dry - I'm taking a long time & have to re-wet and refresh. Perhaps more importantly is the tip to lay the blade angle way down when the flex happens. I've been following the std rule of keeping it at about 30 deg.

In keeping w/ the example of the jawline, where the heaviest grass grows I'm hearing that when the blade bogs down, simply lower the angle alot and keep mowing - assuming lather and edge are fine. What I've done prior to this with the small hollows, was to stop cutting parallel to the jaw line so a much smaller portion of the edge was actually cutting. This was keeping w/ the thinking that the 'speeds or feeds were off' as Joed rightly describes (too much feed or too big a bite on the blade).

That I get it wrong is no surprise as I learn. I'd not heard about what conditions require switching to a much lower blade angle while going WTG. Is it fair to say that lowering the angle is appropriate whenever there's an issue w/ bite or pull? I'd read about atg and xtg requiring the low angle, but not wtg.

Again, thank you. I'm far better off being told I'm wrong than continuing to DO it wrong. I appreciate your help.

There are a some posts on SRP with pics of instructions from razor manufacturers.
Torrey, Boker & Kropp IIRC . They all say to lay the razor nearly flat for the best shave.
Pic is from a Kropp box I owned