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Blog entry by auggy53 posted 02-23-2011 06:40 AM 3368 reads 0 times favorited 7 comments Add to Favorites Watch

how critical are the angles on wood lathe chisels ?

-- rick



7 comments so far

View papadan's profile

papadan

1153 posts in 2024 days


#1 posted 02-23-2011 07:14 AM

They are not critical at all! Seem every turner has to figure out what works best for them selves, the angles at which you are most comfortable holding the chisels will determine what blade angle will work for you. I have a couple chisels that I hold upside down when using. I also have a few that I made myself for a certain cut I wanted. When sharpening your chisels, don’t hone them to perfection, leave the bur. You will like the difference.

-- Carpenter assembles with hands, Designer builds with brains, Artist creates with heart!

View nobuckle's profile

nobuckle

1120 posts in 1417 days


#2 posted 02-23-2011 04:10 PM

If by “critical” you mean the degree of the bevel, there is probably some room to play with. It seems to me that the degree of the bevel can determine how the chisel cuts the material. As I consider the issue a couple of questions come to mind. First, how was it determined that those particular bevel angles were found to be the right ones? Second, would I achieve the same results if I put a fingernail grind on my roughing gouge? How would changing the angle on my parting chisel effect how well it performs. The following picture shows that is some room for angle adjustment.

As you can see, the most flexible, when it comes to bevel angle, is the spindle gouge. I suppose that I look at the bevel angle of my chisels the same way I look at the angles of a cutting tool used on a metal lathe. Upon entering the machinist trade I had to learn how to grind cutting tools by hand. While there was some room to play with the various relief angles, it wasn’t much. If those angle were to steep the cutting point would become weak and tend to break down faster. If the angles were not steep enough the tool would do more rubbing that cutting. After making a good number of the tools you learned what worked and what didn’t. It’s the same with woodworking chisels, whether turning or carving. The goal for the most part is to create a shear cut as opposed to a scraping cut. That being the case it seems to me that the angles would need to be created in such a way so as to obtain a shearing cut.
This may be why those angles are the way they are.

-- Doug - Make an effort to live by the slogan "We try harder"

View Bearpie's profile

Bearpie

2587 posts in 1674 days


#3 posted 02-23-2011 05:21 PM

Fairly critical but you can cut with almost any angle however if the angles are properly ground it cuts so much better and leaves the wood much smoother and takes less sanding. I would highly suggest finding a turning club in your area and taking classes under a proficient turner and picking his brains out. No better way to learn! Some things you just cannot teach yourself and you learn faster by being shown how. Also it is imperative that you sharpen your chisels often. Just feeling the edges is not gonna cut it cause it may still feel sharp when the edge (burr) has already been knocked off! You may only need to run your chisel over the grinding wheel once to put the burr back on! Also it is better to have a single bevel on your edge rather than multiple bevels which is caused by improperly held chisels. Look at Nobuckle’s pictures and notice the angle of the chisel… you see there is one smooth angle, that is what you want to strive for, not multiple angles caused by moving the chisel up or down and getting several angles on the bevel surface. There is no rule set in stone but what works for you, some bevel angles works great for one person and lousy for another. Good Luck!

Erwin, Jacksonville, FL

-- Erwin, Jacksonville, FL

View auggy53's profile

auggy53

159 posts in 1335 days


#4 posted 02-23-2011 05:36 PM

thanks for the comments . now i will feel better about attempting to sharpen.

-- rick

View stefang's profile

stefang

13044 posts in 1990 days


#5 posted 02-23-2011 07:02 PM

Hi auggy. The criteria for bevels as I practice it are sufficiently thin cutting edge to get a nicely cut surface and crisp details, and the trade-off of having an edge durable enough that you don’t have to sharpen so often that you waste too much time or metal off your turning tool.

To sum it up, thin bevels cut better, but don’t last as long as thicker bevels, so you need to compromise on the bevel angle.

Standard grinds are usually done at angle of about 30 degrees more or less and used right off the grinder. Fingernail grinds are usually about 40 degrees on the tip. these angles are fairly optimal for most turning, but you might find it advantageous to grind smaller or greater angles for special purposes. Scrapers can be ground at much higher angles. I do mine usually at 89 degrees.

As mentioned above, it’s more efficient and a lot easier and less time consuming to use you tools straight from the grinder. The exception to this is your skew chisel, which should be carefully honed after grinding. The skew is for fine detail work and finished surfaces that don’t require sanding if done well enough.

Frequent grinding is no problem, but It is a great advantage to use HSS turning tools as overheating on the grinder will not ruin them, as it does with high carbon tools.

-- Mike, an American living in Norway.

View peteg's profile

peteg

2890 posts in 1479 days


#6 posted 02-23-2011 10:26 PM

There are guideline angles that have been accepted over the years by any number of professional turners & I must admit I follow these in general (but do have exceptions), However IMHO there are more important issues to me anyway than simply angle.
SHARPENING, it is critical to have one clean edge ground from the heal to the cutting edge around the entire face of the tool, you will struggle to get a clean cut with multiple bevels on your tools, A lot of people over sharpen their tools, try getting used to using an Ezy lap fine sharpening stone to sweeten up the edge, (just rool around the edge) your tools will last ten times longer
RUB THE BEVEL, your success in clean cutting your work piece will be dependant on the angle you present your chisel to the work and your ability to “rub the bevel”, master this & you will eliminate totally any “dig ins” & nasty supprises.
We all have our favourite angles, but if you get the actual grind sorted and tool position then all thats left now is to Turn, Turn & Turn (practice practice etc)

-- Pete G: If you always do what you always did you'll always get what you always got

View HorizontalMike's profile

HorizontalMike

6938 posts in 1570 days


#7 posted 01-14-2013 07:22 PM

I am in the process of sharpening my first-ever set of turning tools and found this old thread that addresses what angles/bevels should be on various tools. I am bumping this thread because I know there are a few other LJs who are as new at this as I am. Maybe we can talk the above folks into some additional advice. 8-)

BTW, I have the 8-piece set of Benjamin’s Best and a 3-set of their “Versa Chisels”. Glad to hear there is some leeway here, while I go about my first sharpening sessions on my belt sharpener.

-- HorizontalMike -- "Woodpeckers understand..."

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