Sorby long grind jig!

[gasmansteve]

Hi all
Just got the new long grind jig for my proedge and wondered if anyone else has tried it yet?
Just not quite sure what the height setting should be on the jig itself. I got the angle set jig as well but not sure how the different settings relate yet?
Steve

 

[spasm]

Hi steve,

How you getting on with the new jig, as soon as i saw your post i started to look where I could get the jig, turners retreat have it though it is not on their web site yet.
I bought it and it arrived in the post today, i thought it was going to easily give me a long fingernail grind, not the case but with some fiddling about I got the grind a
little longer but not a grat deal.

Spasm

 

[gasmansteve]

Hi Spasm
First chance I have to try it out will be this weekend . I thought it would be the `long grind` solution for me chisels but you think maybe not?
Steve

 

[CHJ]

No Jig is going to give you "A Long Grind Profile" automatically.

No matter which brand or style of jig you use the actual profile achieved is down to the operator.

The dwell time on wheel (belt) of any particular facet of the tool determines the amount of metal removal and it is this that forms the profile, all the jig will do is allow you to swing the tool in the same arc consistently.
The arc you swing the tool tip in relation to the abrasive determines what profiles/angles are achievable.
You need to study the effects that both the distances of the pivot point of the jig and the length of protrusion of the tool tip have on the shape produced, they have a complimentary effect working with the jig angle setting.

The position of the tool tip on the curve of the wheel (or belt slope) also has a marked effect, so height of pivot point comes into play with the tool protrusion.

There is no one definitive setting for any grind, once you have determined the settings for your particular setup and the shape/angle you prefer for a tool then note them for future use.

Those settings may well be different for each and every tool dependant on your preferences.

To save constantly changing settings I have three 'bowl gouge' jigs based on the Tormek pattern (same as used by Sorby) set to different angles for different gouges, but even then the spacing distance of the pivot point (base) from the wheel and the tool tip protrusion is again different for some profiles.

Spacers and setting blocks carry the angles and tool details on each so that when diving into the draw weeks latter I don't have to scratch my head as to which settings are needed.

If at all possible try and standardize on a pivot base/wheel (belt) centre height that will give you the profiles you require by adjusting the swinging jig dimensions/angles, that at least will remove one variable.

The very long Ellsworth ? grind is the most difficult to achieve with the jig.

Each tool manufacturer may, even will, have a different flute profile this will also mean that what is good for one gouge won't work with another, only the operator watching how much material is being removed on each facet is the only determination of shape.

 

[boysie39]

I would agree with Chas. Find out what your preferred grinds are and quickly . You can make a gouge very short in a short time messing around with different grinds.

In our club most of the turners grind freehand, I have jigs (and reels) but would love to be able to freehand.
In the lenght of time it takes to set up the jig they are back turning, It dosent make any difference to me as
I just do it for a hobby,but anyone in production can save a lot of time.
One turner has 2 or 3 facets on a gouge and it works for him,I'm happy to get one decent one on mine if I can

 

[gasmansteve]

Hi all
Tried my long grind jig for the Proedge today and have to say I`m very pleased with it. Got maybe an extra 1/2" to 3/4" side grind on it and maybe if I use the outer hole for the jig an even longer side grind can be achieved but its spot on for me.
Using the marker gauge I use 40degs for my spindle gouges and 45 for the bowl gouges.

There are 4 variables with the jig and each of them have many positions but this is my setup on the jig.

Steve

 

[chrisbaker42]

I may have to invest in one of these to go with my pro edge, looks like it gives good results.

 

[myturn]

If you are going to use a jig to grind then don't worry about getting an exact replica of some ideal profile you are trying to replicate.

Get it close enough and familiarise yourself with how the tool behaves then you know you can quickly sharpen it using the jig and get back to work in less than a minute.

The main thing is to have sharp tools and if you know you can sharpen them quickly you will be more inclined so do so.

That is what I have done. My profiles are based on Richard Raffan's recommendations but he does his freehand and I use a jig so I experimented with the jig settings to get as close to Richard's profiles as I can. Once I familiarised myself with the way the tools behave using his profiles turning has become a much more relaxed affair and I can sharpen them as frequently as needed without spending any time at it.

 

[spasm]

Hi Steve,

Can I ask you a couple of questions, what setting id the nuckle set on 1 2 3 4 0r 5 I'm useing the word nuckle to discribe the part you put the chisle in and how far does it protrude out of the nuckle.
my other question is what is the shaft ajustment set at the nearest number on the shaft or if you prefer the distance from the nuckle to the shaft ajuster, the grind you have achived does look good.

Thanks Spasm

 

[gasmansteve]

Hi Spasm
Can`t remember off the top of me head what the various dimensions are but I`ll post a pic tomorrow. Must admit when you said you never saw much of an improvement I didn`t expect too much and I haven`t bothered using the outer hole which would suggest an even longer grind but its fine for me as it is and it gives a nice straight edge to the grind now which it didn`t before. Not sure what the allen screw at the bottom is for? if you tighten it then the bar won`t swivel ??
Cheers
Steve

 

[gasmansteve]

Hi all
Hope you can see the dimensions I have on my jig, this one gives 45degs for the bowl gouge. I don`t have a datum line on the knuckle joint on my jig so not sure about the number to use but you can see the angle from the pic.

I`d be interested to see what others get using the other holes on the jig
Cheers
Steve

 

[spasm]

Hi steve,

thanks for posting the photos haven't been able to re-set my jig as yet but hope to do it soon, week end will be busy as my son is getting married but will get round to doing it as soon as pos i'll let you know how I get on.

Spasm

 

[gasmansteve]

Hi Spasm
No problemo, hope all goes well with the wedding! Got my last one married off last year
Steve