New saw advice

[scrimper]

Does the Hegner quick release clamp fit? I don't know but would expect it would. Alternatively you can make your own using 4mm threaded bar with a couple of nuts and lever turn it - I use a small mole grip as the lever and it works fine.
Brian

Yes it does fit, but it's not as simple as that to make your own. The Hegner quick clamp has a rotating piece at the inner end of the 4mm thread which stops the tendency of the blade to twist as you tighten it.

Martin,

I accept that Hegner Quick clamp has rotating piece as you say and I can see what they are saying about the blade's potential to twist. I've never noticed problems with the blade twisting using my method above. Mike's workshop has a lever that's been mentioned on here before and so far as I can see there is no rotating piece on that either ie its just like the method I use. Mike does make it clear that his lever is not a Hegner product.

Brian

My Hegner quick clamp does not have the rotating piece in it but I have never found it's absence cause any problems. I bought my Hegner in 1999 so it may be an earlier design quick clamp.

 

[martinka]

Martin,

I accept that Hegner Quick clamp has rotating piece as you say and I can see what they are saying about the blade's potential to twist. I've never noticed problems with the blade twisting using my method above. Mike's workshop has a lever that's been mentioned on here before and so far as I can see there is no rotating piece on that either ie its just like the method I use. Mike does make it clear that his lever is not a Hegner product.

Brian

Hi Brian, the ones Mike sells, as far as I can see, are just standard Bristol/indexable handles that he makes available to those who may not know about them, and it's a cheap alternative that does work. They ought to be especially good for people who have problems with grip, although I remember one of our forum members bought one but didn't like it. I've used one myself on a Jet saw (I pinched it off my mill although on that one the screw is used to close the clamp and doesn't bear on the blade.

My Hegner quick clamp does not have the rotating piece in it but I have never found it's absence cause any problems. I bought my Hegner in 1999 so it may be an earlier design quick clamp.

I didn't know they made one like that, John, though it's not surprising I didn't know as mine is the only one I have seen. It'd work the same as the old Draper setup I used which clamps between two allen screws. The one I used did twist the blade until I squared up the ends of the screws in the lathe. No doubt Hegner would square the ends of the screws during manufacture. The correct pressure helps as well, and as an experienced scroller that's something you would get right, so I am not surprised you never had a problem.

 

[Bryan Bennett]

The blade clamp that Mike sells for the Hegner seemed alright when I first started using it,it then started to bend the top of the blade.The problem might have been of my making by over tightening,I modified the Hegner quick clamp by drilling the edges and putting small steel dowels in.It now works very well.If has Martin says the end of the clamp screw does't rotate the screw will bend the top of the bend.
When I bought my Hegner,the quick clamp was a black steel plate,that you put under the screw on the top arm,when held in place you released the blade then put the hole,tighten the blade and release the steel plate. Tension the blade and carry on.

Bryan

 

[finneyb]

Martin,

Assuming we are talking about http://www.hegner.co.uk/Quick-Clamp-for-Piercework and we are not at cross purposes. I'm having difficulty understanding and visualising the rotating bearing surfaces within the quick clamp to prevent the blade twisting when tightening up. Can you help?

Another method may be to mod a push bike wheel quick release - subject to dia being suitable and length being adjustable. The shaft would need to pass through the thread and bear on the outside of the blade clamp. Then there would be no torque on the blade when tightening the force would be along the axis of the QR.

Brian

 

[martinka]

Martin,

Assuming we are talking about http://www.hegner.co.uk/Quick-Clamp-for-Piercework and we are not at cross purposes. I'm having difficulty understanding and visualising the rotating bearing surfaces within the quick clamp to prevent the blade twisting when tightening up. Can you help?

Another method may be to mod a push bike wheel quick release - subject to dia being suitable and length being adjustable. The shaft would need to pass through the thread and bear on the outside of the blade clamp. Then there would be no torque on the blade when tightening the force would be along the axis of the QR.

Brian

Here y'go Brian. I pulled it out a bit so you can see it better. It is held in place with a tiny o-ring.

The Delta blade clamps work on a similar principle to the bike quick release, although it closes the two sides of the clamp together instead of having a rod through

 

[finneyb]

Martin,

Thanks for the photo.
I need to think about it - I can't see the use/need of the rotating piece.

Brian

 

[scrimper]

Martin,

Thanks for the photo.
I need to think about it - I can't see the use/need of the rotating piece.

Brian

As I mentioned my clamp does not have it and works well without but I do see the point of it. The best saws have a true parallel action which is not 100% possible with the blade fixed in the top arm so with the normal Hegner clamp the knife edge allows the blade and clamp to pivot slightly and correct any see-sawing motion that the moving arms exhibit by design! this is why the top knurled knob is not normally tightened down on the clamp.

With the piece work clamp the idea is that the knurled knob IS tightened on the the clamp to hold it in place for quick piercing changes, the rotating part that Martins clamp has allows the blade to pivot inside the clamp thereby ensuring a truly parallel motion.

With my clamp without the rotating part I just leave the top knurled knob slightly loose allowing the pierce clamp to pivot slightly but not enough to let the clamp fall out, this then gives me a almost perfect parallel motion but the one Martin has is better.

 

[finneyb]

The best saws have a true parallel action which is not 100% possible with the blade fixed in the top arm so with the normal Hegner clamp the knife edge allows the blade and clamp to pivot slightly and correct any see-sawing motion that the moving arms exhibit by design! this is why the top knurled knob is not normally tightened down on the clamp.

With the piece work clamp the idea is that the knurled knob IS tightened on the the clamp to hold it in place for quick piercing changes, the rotating part that Martins clamp has allows the blade to pivot inside the clamp thereby ensuring a truly parallel motion.

Sorry guys still can't see it.
I agree with Scrimper about parallel action, pivoting etc. But I don't see how the rotating piece allows the blade to rotate.

In a 'knife edge' blade clamp the blade is held in place by compressing the two legs together. This is the case with both the standard method and the pierce work clamp. I don't see how the blade can rotate within the p/w clamp when it is sufficiently compressed between the legs to retain the blade.

Looking at Martin's photo - the clean thread on the right must be in the threaded right hand clamp leg and the knob screwed hard against the other leg to pull them together and retain the blade. The rotating piece must be a smaller diameter than the clamp thread otherwise it won't pass through; so how does the rotating piece that is not in contact with the blade clamp allow the blade to rotate?

Brian

 

[scrimper]

The best saws have a true parallel action which is not 100% possible with the blade fixed in the top arm so with the normal Hegner clamp the knife edge allows the blade and clamp to pivot slightly and correct any see-sawing motion that the moving arms exhibit by design! this is why the top knurled knob is not normally tightened down on the clamp.

With the piece work clamp the idea is that the knurled knob IS tightened on the the clamp to hold it in place for quick piercing changes, the rotating part that Martins clamp has allows the blade to pivot inside the clamp thereby ensuring a truly parallel motion.

Sorry guys still can't see it.
I agree with Scrimper about parallel action, pivoting etc. But I don't see how the rotating piece allows the blade to rotate.

In a 'knife edge' blade clamp the blade is held in place by compressing the two legs together. This is the case with both the standard method and the pierce work clamp. I don't see how the blade can rotate within the p/w clamp when it is sufficiently compressed between the legs to retain the blade.

Looking at Martin's photo - the clean thread on the right must be in the threaded right hand clamp leg and the knob screwed hard against the other leg to pull them together and retain the blade. The rotating piece must be a smaller diameter than the clamp thread otherwise it won't pass through; so how does the rotating piece that is not in contact with the blade clamp allow the blade to rotate?

Brian

Actually, thinking about it, I would say that the rotating part is more to do with stopping the blade moving out of line in the clamp as you tighten it!

 

[jonluv]

One superb Delta on Ebay up for grabs--- could not do better-- read reviews

John

 

[finneyb]

Actually, thinking about it, I would say that the rotating part is more to do with stopping the blade moving out of line in the clamp as you tighten it!

Scrimper thanks - I've seen the light

Brian

 

[martinka]

Actually, thinking about it, I would say that the rotating part is more to do with stopping the blade moving out of line in the clamp as you tighten it!

Which is what I said in my first post in this thread.

 

[scrimper]

Actually, thinking about it, I would say that the rotating part is more to do with stopping the blade moving out of line in the clamp as you tighten it!

Which is what I said in my first post in this thread.

And looking back at said post I can confirm that you did. (hammer)

In which case considering that mine does not have said rotating part and that I have never had any problems with twisted blades when tightening perhaps Hegner make too much of this 'rotating wonder'! :mrgreen:

 

[Stooby]

Just a follow on question about the AWFS18. On the axminster site there is a section with a review of the Excalibur saying it is an excellent machine, better than the AWFS18 for fretwork as the arm lifts. They compare the AWFS18 to a machine with a difficult to remove blade. Sorry I closed the page and can't find it again, I got there by following the link sometimes at the top of this forum to a woodturning event. That type of small fine work is one of the reasons I want to move away from my current saw.

 

[martinka]

The advantage of the Excalibur (and, I think, the DeWalt) is that you can feed the blade through from the top. There's no denying the Hegner/AWFS18 can be a pain to feed the blade from the bottom once the job gets above a certain size or if the cut is in the middle of the job. In fact I ground some of the top arm stop away from the back of the frame so that the top arm would lift a bit further to give more room. A down side to this is that the louder bang when a blade breaks has turned me into a nervous wreck.

 

[finneyb]

In which case considering that mine does not have said rotating part and that I have never had any problems with twisted blades when tightening perhaps Hegner make too much of this 'rotating wonder'!

Also, I feel that the Hegner pierce work clamp is poor design in that it will tend to spread the legs of the knife edge clamp, causing them to prematurely fail. If I understand correctly how it is used.

The standard use of the knife edge clamp compresses the legs together so it cannot be over stressed by tightening.

Brian

 

[Stooby]

The Excalibur seems to get bad reviews but is this not a big advantage?

 

[martinka]

Also, I feel that the Hegner pierce work clamp is poor design in that it will tend to spread the legs of the knife edge clamp, causing them to prematurely fail. If I understand correctly how it is used.
Brian

I believe John (Scrimper) has had his since 1999, so if it's going to fail prematurely, it better hurry up. :mrgreen:
Given the small amount of pressure needed to hold a blade, I really don't think it is going to happen.

 

[Philip n]

A youtube video from an Australian scroller pointing out the issues with the excalibur saw.

https://www.youtube.com/watch?v=FfEg7uL2SVM