sharpening a v cutter

This topic has 8 replies, 5 voices, and was last updated 12 January 2013 at 15:58 by Sub Mandrel.

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30 September 2012 at 21:30 #6366
Ian Welford
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@ianwelford58739
using a boxford t&C grinder
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30 September 2012 at 21:30 #99767
Ian Welford
Participant
@ianwelford58739
Any suggestions please for guidance on how to set up a Boxford T&C grinder to sharpen a 4" dia V cutter ( 90*) . I've got the manual but am struggling to work out whether to grind the front face of each tooth first. Afterwards I will need to grind the side of each tooth as the lands are quite large. Is there a link to any demo of this process that anyone knows about ?

The cutter is HSS and will be used on steel so I am assuming a 5 to 7* clearance would be correct (???)

Cheers Ian
30 September 2012 at 21:42 #99768
John Stevenson 1
Participant
@johnstevenson1
Ian,

Front face is always ground last. If you can it always pays to grind one face one way and the other face the other way.

Silly as it sounds but the burr thrown off helps to keep the edge hence they want staggering.

John S.
30 September 2012 at 21:56 #99771
Ian Welford
Participant
@ianwelford58739
Thanks John

Maybe that explains why the front tooth faces show evidence of the front face being gound back in 2 stages. I assumed the previous set up had just not been properly checked but maybe it was deliberate!

Any suggestions of how wide I should get the lands? On a second cutter I have they're about 50" wide but this one's more like 75" so due a sharpen ( plus the tips are visibly blunt !)

Plucking up courage to have a go !
8 January 2013 at 21:48 #108244
Ian Welford
Participant
@ianwelford58739
Finally plucked up the courage and found the time to sharpen it today. Hasn't yet been used in anger ( tomorrow or thursday perhaps )but seems a lot sharper under magnifier and edge chipping has gone!

John – I have just stoned the front face with a diamond file as had done multiple set ups and measure ups all day to get the results right(ish), .

Also had to lubricate the Boxford thoroughly as hasn't been used "full range" for a while so slide ends etc sticky and tiring on the handwheel. Then the grease gun leaked, then couldn't find the grinding finger I wanted so 3 more made etc, etc. By this time I was knackered

Now a further question- how do you "true up" a diamond wheel bought from Arc Euro (happy customer, no connection to firm etc)?

Obviously ( or maybe it isn't) I can't use a diamond or can I ???

Ian
8 January 2013 at 22:53 #108251
Bubble
Participant
@bubble
Hi Ian

re diamond wheel "truing"

Truing and cleaning are two separate issues.

First, truing ie getting the wheel to run true without "wobble". I have limited experience of one Arc Euro wheel, for use on my Quorn to shape/sharpen home-made brazed carbide-tipped boring bar tools.The wheel as received was pretty good but I decided to experiment! I reverse mounted the diamond wheel in the 3-jaw Griptru chuck (face and jaw runout checked/adjusted beforehand), and took a light cleanup skim on the back face of the aluminium body of the wheel.This was then checked for parallelism on the surface plate using a vernier height gauge. I also took a cleanup skim out of the bore. The wheel was then permanently mounted on a Chaddock-style arbor for use in the Quorn.

It appears to work ok, ie the whole circumferential diamond face gets used, and the assembly balance was good.

Second, cleaning. I have not tried this, but have read that a white aluminium oxide stick is used to refresh the diamond surface. This abrades the resin matrix and exposes the diamond particles. You stop when the alum. oxide starts to be cut away by the diamond. I recall from somewhere that the sticks are expensive to buy, but I suspect you could use an old grinding wheel (caveat experimentor!) I have also read somewhere that you can use a piece of natural limestone to clean. Maybe someone else here can confirm/deny this?

Hope this is of use.

Jim
10 January 2013 at 21:24 #108403
Ian Welford
Participant
@ianwelford58739
Thanks for that Jim

Slight embarrassment, when using today I notied that I have sharpened one edge of V cutter at 6* and the other at -6*.

One edge cut beautifully, the other bounced and is to be reground tonight !

Re Cleaning of a daimond stone – the Staedtler plastic type rubbers work well on diamond stones ( which I use for wood working) when they get clogged. Trend diamond fluid is also excellent at floating off particles.

I was more concerned at getting the edge to run absolutely true and also dressing it to a finer edge ie thinner edge.

Oh well back to the grinder!

Ian
10 January 2013 at 22:21 #108408
David Littlewood
Participant
@davidlittlewood51847
I mounted an AET diamond wheel in my Clarkson a couple of years ago and it ran true without any adjustment. Worth a try!

David
12 January 2013 at 15:58 #108472
Sub Mandrel
Participant
@submandrel
As the diamond wheels from Arc have alloy bodies, they can be rigidly mounted to the grinding spindle (unlike grit wheels.

For my T&C grinder I fitted a bush to one end of the spindle, then mounted the entire thing in the lathe using the centres in the spindle(!) I hurned the bush to a close push fit in the wheel and made an alloy washer to retain the wheel using the original nut. The wheel is still so true you can hardly tell it is rotating by looking at it.

Neil
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