Chisel Dig In

[ozwinner]

Hi all
This has probably been covered before but I did a search.........and here I am.
I keep getting "dig in" when turning with gouges that I have just sharpened.
Can you guys tell me why.
And before ya can say it Stoppers, I know, I'm an idiot.........:D
Cheers, Allan :)

[Christopha]

Dear Fellow Idiot,
Is it possible that your sharpening leaves something to be desired? Like.... how many bevels can you see on the tool after grinding?
If you have ground the gouge correctly then it can only be that you haven't got your bevel supporting the edge, remember that your toolrest is just that, a rest, it's there to stop your toll from progressing immediately toward the bed of the lathe in a less than exciting manner. Any "leverage" (????) used is using your bevel as the fulcrum if you like, you should be using the bevel to control the depth of cut and your backside to control the whole shooting match. Also, as it is your gouge you are talking about and I am assuming it is your spindle gouge, don't wait till your are half downhill into a cove before you start to roll, lift and swing your tool, most newchums make this mistake, suddenly realise and try to correct it..... dig in!
I hope I have been of some help, good luck, if I haven't been any help then I shall leave you the tender(?) mercies of Doorstop.

[reuelt]

The tool rest should be positioned a little higher than the lathe center, and you rest the gouge on the tool rest and on top of the work piece, holding the Gouges not directly perpendicular to Lathe Centre but about 45 degrees to the right or 45 deg to the left (depending on the direction of cut you are moving). Then slowly pull back the gouge slowly so as to cut the wood smoothly wood a little at a time.

When grinding the gouge, the bevel angle should be between 30-35 deg.

Hope that helps

[gatiep]

There is no hard and fast rule regarding the angle of the tool to the work or even the tool rest height. It is a combination between the angle on the tool and the tool rest height. The turners height dictates the tool rest height to get the bevel rubbing.

I'll try and clarify. Normally a lathe should be set up so that the spindle height is the height of the turners elbow. Now if this is not quite true because of a short turner and a tall turner working on the same lathe, the short guy will have to set his tool rest at a different height than the tall guy to get the bevel rubbing. Also if the bevel angle on the tool changes, the tool rest height changes for the same height person to rub the bevel....unless the turners are happy to end up with back ache.

Often changing the tool rest height by as little as 2 mm makes the difference between slicing the timber or just having a go at it.

We all know if the bevel doesn't rub, the tool digs in. Set your toolrest so that the bevel rubs and you are in a comfortable position. Have a go...yeah its slicing beautifully. Now change the bevel angle on the tool by making the angle 'sharper', ever so slightly. Get back to turn with exactly the same tool rest height and stance.....bet you there is a dig in coming or else you will subcontiously change your stance to get the bevel rubbing and possible end up with a krook back if u keep on turning in that position.

This is very easily observed in a class of wood turners of various heights, to make the bevel of tools sharpened to the same bevel angle rub, the tool rest height will be different. That is assuming that all the lathe spindle heights are the same.

A long winded way of putting my observation accross...sorry abt that.

Cya
Joe


Have fun.....................keep turnin

[reuelt]

Thanks Joe for a V. Outstanding clarification.

I like and so follow closely
Russ Zimermans' "Three Principles of a clean cut:-
1. The cutting edge should be about 45 deg to the direction in which the work is rotating.
2. The tool bevel should be rubbing on the wood and
3. Finishing cuts should be made across, not against the wood fibers.


I note that Ozwinner was saying that a "just shapened" tool digs-in meaning that a blunt tool seems to work better.

My analysis is that he is PROBABLY doing more wood scrapping (blunt tools can scrap) than wood slicing (sharp tools can slice) so the way he holds the gouges MAY need reviewing.

[ozwinner]

Hi, me again
Well I tryed all your advice today, thank you all.
I lifted the tool rest 1-2mm, and resharpened the chisels.
Results are better, I found that in the case of spindel speed, faster is not better.
I'm a rev head, I cant help it.
I tryed the 45 degree approach, some times it works, other times not, it must be the angle of the grain which I must also consider.
I recently purchased a wet grinder, its a Tormek so all chisels in the shed are sharp, and to the correct angle, and with no facets which a joy to behold.
Next thing is, practice, practice, practice.
Thanks again, Allan :)

[JackoH]

Please try to get to a Woodies Club. There's one at Eltham, and probably nearer to you than that.(See list of clubs on this sites home page, in the column on the left!)
These clubs are packed with enthusiastic people who will be only to glad to give you all the help you need.
Failing that PLEASE Get some lessons!!!!:mad:

[BigPop]

I totally agree with John.

GO AND GET SOME LESSONS!!!!

Up till 3 weeks ago I never knew what a tailstock from a headstock was nor a roughing gouge from a parting tool let alone a skew.
If you would have asked me to turn some beads and coves I would've given you blank stare. I had never before touched a woodlathe other than to use the sanding disc when I was in 1st form at High School. We never got to use the lathe for turning and after 2 weeks ended up in Metalwork class for the rest of our schooling days. ( Were supposed to swap and change around between the 2 but because they had to re-furbish the woodwork rooms we never got to go back.)

I have enrolled in a Woodturning Course at TAFE and its the best thing I have done in years. Have now been going for 3 weeks and although I can just get by with my turning at least I know how to 'rub the bevel' and turn beads and coves and can now even make rolling pins so SWMBO has another weapon to use in the kitchen.

But definitley get lessons you will never look back that's for sure. I now have the 'basic' knowledge and with more practice can only get better.

Best fun I've had in years that's for sure and am now getting brownie points from SWMBO also (which helps when it comes to toy buying time)

[JackoH]

Big Pete.
THANKYOU,THANKYOU,THANKYOU!!!
I started my woodturning about 5 years ago in exactly the same way as you.
There is no substitute for a course of basic lessons, after which you can read all the books and watch all the videos, understand them, and put their ideas into practice.
As for the Tormek Sharpening system, It's too bloody slow.
Once you get the hang of putting an edge on turning chisels it takes only one or two passes to touch up the edge on the 8 inch grinder.
As Dick Sing told me "I grind them once, and after that I sharpen them".:D
( Dick Sing is an American turner. Those of you who have been lucky enough to meet him and watch him turn on his visits to Oz will know that he is a big bloke with big hands and yet turns the smallest items, including jewelry. He has also published several books including the pen makers bible "Pens From The Wood Lathe". );)

[ozwinner]

Hi Guys
Well I figured it out.
The chisel set that I bought Record Power, yeah I know.............., but for a newby they are ok.
Well anyway, the spindel gouge was ground at 90 degrees on the end, instead of being a radius.
I reground to a radius and Eureka it dont dig in. :D
Thanks for all the advise.
On the subject of clubs, woodwork or otherwise, I have been a member of a number of clubs and there always seems to be a club Nazi.
There is always one person who thinks they own the club, the other clubs were gem clubs.
Maybe it was the silicone oxide in the air, might not be the same with wood clubs, but I aint too keen to find out.
No thanks, I'll try to nut it out my self, or I'll ask friends, like I did here.
Cheers, Allan :)