Sharpening Jig set up.

[kjmc1957]

Hi All

Now that I'm back to turning I want to start with a set of sharp tools (bit of a treat) I've sharpened by hand before now but I ended up with a gouge with an end that looked more like a ballroom glitter ball than a serious cutting tool, I have set up the Tru-Grind jig, even after watching the video a good few times I still can't produce a 'swept back wing' I've got the jig set at indent number 4 and the slide in as far as it goes, does anyone have a set of indent/slide figures that work?

Many Thanks

Kevin

 

[wizard]

Why use a bench grinder when you have a lathe, I use the faceplate with sanding discs for grinding then hone on wet and dry paper on a surface plate.

 

[Jacob]

Why use a bench grinder when you have a lathe, I use the faceplate with sanding discs for grinding then hone on wet and dry paper on a surface plate.

Agree. Or a belt sander. Bench grinder the worst option by far unless you only use the flat side of the wheel. And if you get away from jigs, sharpening gouges becomes as easy as sharpening a pencil.

 

[Spindle]

Hi

I have no experience of the Tru Grind system but if its anything like the Tormek jig you will have to progressively grind back the wings by rolling the gouge further and further to the sides. I didn't bother trying to go the whole hog in one session - I just ground the wings back a little further each time I sharpened the gouge until I reached the profile I wanted.

I like the repeatability of grind that a jig affords me and whilst I have used the lathe to sharpen tools it's a b*****r having to remove the work when the tool gets blunt :roll: Grinder for me every time.

Regards Mick

 

[Noggsy]

Bench grinder is the worst by far??

It takes me about 30 seconds in total to sharpen both of my large bowl gouges, mid-bowl, using a jig and bench grinder. It would take longer than that to take the bowl off the lathe and put whatever I was using to sharpen the tool back on it. I would then probably knock the chuck over, damage the bowl and then go back into the house in disgust.

It's obviously horses for courses, but I find a jig essential to get repeatability. I'm not saying I couldn't eventually develop the technique required for freehand grinding, but why bother? Life's too short and I know that loads of pro turners use them, so they clearly have their place.

 

[finneyb]

Noggsy +1

 

[nev]

I am still getting used to the wolverine set up i have, but one thing i have realised is that the jigs (only?) control the angle of the bevel, the shape etc is still down to the operator, the swing, the roll and the time in contact with the wheel.
If you dont have a tool you can copy You can get profiles ....
http://www.henrytaylortools.co.uk/profi ... tools.html
which make getting your head around the angles and sweeps a little easier?

 

[YewTube]

one thing i have realised is that the jigs (only?) control the angle of the bevel, the shape etc is still down to the operator, the swing, the roll and the time in contact with the wheel.

Nev has this right. Using the settings lets you reproduce what you did before. If you want to put a swept back grind on a gouge for the first time then have a look for the grind you want. Nev's link will give you some ideas. Study the grind and get the shape of the cutting edge in your minds eye. By this I mean just the edge not the facets. You should see a shape like a parabola.

The next thing to do is not exactly intuitive. With the gouge out of the jig turn it over and put it flute down on the grinder and pointing towards the wheel. Proceed to grind the 'cutting' edge until the profile on the inside edge of the flute is the shape you have in your minds eye. You will have to push the gouge up and down the wheel to get the profile.

When you have finished it will be 'a little' to 'seriously' blunt. Now put it back in the jig with whatever settings you want and grind off all the metal on the outside until you reach the inner profile. You will now have a perfectly symmetrical grind that will be the envy of all your friends.

Bill

 

[wizard]

this is what i use

 

[Spindle]

Hi Nev / Bill

I think you will find that the further you angle the jig towards you the more elongated grind you will be able to achieve - the jig most certainly influences the profile.

Regards Mick

 

[nev]

Hi Nev / Bill

I think you will find that the further you angle the jig towards you the more elongated grind you will be able to achieve - the jig most certainly influences the profile.

Regards Mick

I agree 100% Mick, what I am trying to say is that a jig set at your desired angle controls and maintains a constant angle of the bevel but the sweep/ dwell time etc also go a long way towards the final shape of the grind.
Before i purchased the wolverine I rather naively thought that a jig would be an instant, no skills required answer to bevel grinds, set the angle etc hit the grinder and voila alas this is only applicable to flat gouges, everything else requires some practice and dexterity :roll:

 

[kjmc1957]

Thank you all for your help, OI think Nev is right, the jig repeats the presentation but the operator controls the final shape.;

Now if I can ask for yet more knowledge, I have the Axminster AWDWSG Wetstone Grinder which appears to be a Tormek lookalike, would this be a better option, using the slower water cooled wheel? I think I have the jig to go with it somewhere, moved house 2 years ago and I've only just got a lathe in the last 4 weeks so I'm not sure where what is, but if I've got it' is it a better finish than the faster white wheel?

Regards

Kevin

 

[Robbo3]

The point to remember about sharpening is that you are taking off the minutest layer of metal that is possible to obtain a sharp edge. That is why some people prefer to hone the edge with a stone, only going back to the grinder after several honing sessions.

Reshaping a chisel/gouge is not sharpening although a sharpened tool should be the end result.

Try to keep a list of the settings used for each individual tool. Makes things so much easier next time you have a sharpening session.

 

[YewTube]

Hi Nev / Bill

I think you will find that the further you angle the jig towards you the more elongated grind you will be able to achieve - the jig most certainly influences the profile.

Regards Mick

Sorry Mick but I have to disagree. The elongation of the grind is governed by the time you spend grinding it irrespective of the angle of the jig. In fact if you set the jig to 90º, tilt it round so that you are at the extreme of it's travel and grinding the side of the gouge. In this position you could put a side grind down to the handle, if it wasn't for the jig getting in the way.

I have found a video of what I was trying to describe in an earlier post. The real action starts at 6min and some of the action is out of shot but there is enough to show the technique.

http://youtu.be/AAocVE7X_3U

Bill

 

[Random Orbital Bob]

To see the action of an articulated bowl gouge jig actually in action for a fingernail grind....just youtube for Jeff Farris. He's the US Tormek demo guy and it's in one of his uploads somewhere.

I use both a bench grinder and a Tormek. The bench grinder I use for shaping ie lots of steel removal because it's fast and not about sharpening, its about steel removal. The water stone is about finessing the sharpness to a 1000 grit or better if you strop it also.

Those articulated jigs are superb, absolutely indispensable in my view. As long as you exactly repeat the protrusion of the tool from the jig and the angle of the jids set screw...your bevel angle will always be identical ie a single facet all the way round....literally like a factory grind...perfect every time. The amount of fingernail you get is down to the operator. More time you spend on the sides against the wheel, the more steel you will remove. Obviously you want the grind to be symmetrical so you need to spend equal effort on the two extreme sides and virtually no time dead centre.

The length of the side grind is also affected by the jig set screw settings, in conjunction with the operator as described above.

So to summarise: articulated bowl gouge jigs have a hard setting which affects the geometry of the side grind but that potential fingernail grind isn't realised until the operator actually (and somewhat laboriously) executes the grind. For this reason, particularly as we're talking about HSS with turning tools (very hard), if your bench grinder is jigged with the articulated jig then do the bulk of the fingernail grinding on a course grit wheel. Then refine and forever thereafter sharpen on the whetstone wheel. This will then keep a very fine edge and maintain your fingernail grind. The hard part is getting the factory angle to the fingernail grind in the first place. Expect to spend up to an hour with a factory grind to a long fingernail grind (like an Ellsworth for example)

 

[KimG]

I use the Sorby jig with my bench grinder, a record with an 8" wheel, I find it quick and easy to maintain a good shape and edge on my gouges. The jig allows me to get a precise and repeatable shape with the minimum of steel removal and makes sharpening a quick job. I can't see it being worthwhile honing a gouge with a flat stone unless you are doing something exceptional because the edge does not remain long enough to make that amount of effort pay. A Skew chisel, yes, but I find gouges perform great straight off the grinder.

 

[Spindle]

Hi Bill

We'll agree to differ then - but if you've time to experiment you'll see that in one extreme setting of the jig it will produce a useable grind with swept back wings. In the other extreme you can produce the same profile but the angle of the grind on the wings make the tool unusable. (Not suggesting that you actually go to the lengths of grinding the tool - just offer it up).

Regards Mick

 

[Robbo3]

Kevin - Presumably the original CD or paper instructions are not available to give you a starting point.

If this is the video referred to - https://www.youtube.com/watch?v=eP8R_rgbL5A
then it would seem that the instructions only refer to dressing the angles already ground on the tools & not changing or creating your own.

From the advanced gouge section (at about 6 minutes) the commentator blithely says "adjust the angle to 55 degrees" but fails to say how this is achieved or how to measure it.

This type of system has three adjustments:
Tool protrusion
Jig hinge angle
Pivot position

These adjustments are inter related so that if one is altered the other(s) may need adjustment to compensate.

The Sorby jig is mounted at a fixed distance from the wheel thus the grind angle is set by the amount of tool protrusion.

IMO the actual angle is irrelevant. For a bowl gouge it probably needs to be 45 degrees or steeper to allow it to get round the bottom of a curve. If you already have a suitable angle on the tool, try & mimic it. Place the tool in the jig, mark the face of the tool with a marker pen & with the grinder unplugged, rest it lightly on the wheel whilst turning the wheel upwards by hand. This will show you where the grinding will take place & you will have to use some judgement to see if it is acceptable or whether the grinding angle (not the jig hinge angle) needs to be adjusted.
Once you have set the jig, tighten everything up, turn on the grinder & everything else is then up to you.

Also remember that different makes of the same gouge will not neccessarily allow the same shape of grind to be achieved
- http://www.woodcentral.com/newforum/grinds.shtml
- http://www.peterchild.co.uk/info1/sflute.htm

Tru-Grind
- http://www.philirons.com/shop201108b/in ... ductID=268

HTH

 

[YewTube]

in one extreme setting of the jig it will produce a useable grind with swept back wings. In the other extreme you can produce the same profile but the angle of the grind on the wings make the tool unusable.
Regards Mick

I agree with this statement. I was having problems with the following.

I think you will find that the further you angle the jig towards you the more elongated grind you will be able to achieve.

Which I took to mean that you set the included angle of the jig to 180°.

Perhaps you could clarify?

Bill