Sharpening Fine tooth slitting Saws

[WorkshopPeteParticipant @workshoppete]

Buying CBN grinding wheels

[WorkshopPeteParticipant @workshoppete]

Does anyone know where you can but a CBN grinding wheel to sharpen fine tooth slitting saws ideally 5 or 6 inches dia. I am thinking of a saucer/dish wheel with material on both the face and angled back side so a plunge grind would shape both the tooth face and the back of the next tooth.

thanks

Peter

[egaParticipant @ega]

Good question. I would like to know, too.

In the meantime, ARC do diamond wheels that, suitably applied, might do your job.

Edited By ega on 18/05/2020 08:08:49

[David George 1Participant @davidgeorge1]

Hi Peter why has the wheel have to be CBN as I would use a white aloxite wheel for that readily available from most grinding wheel supliers.

David

[egaParticipant @ega]

Posted by David George 1 on 18/05/2020 08:13:58:

Hi Peter why has the wheel have to be CBN as I would use a white aloxite wheel for that readily available from most grinding wheel supliers.

David

Perhaps because by the time you are part way round the saw the white wheel will need to be dressed?

[WorkshopPeteParticipant @workshoppete]

Thanks ega

The problem with Diamond is its not good for grinding HSS where as CBN is ideal and unlike conventional grinding wheels maintains its shape. Someone must do it the professional cutter sharpening companies can do it so there must be something out there but where. I must have at least a dozen cutters that are all in need of treatment accumulated over years in our hobby.

Another thing does anyone know why the hole on a slitting saw is slightly eccentric? they all seem to be this way and its not the arbor.

Peter

[John CParticipant @johnc47954]

Hi Pete, This thread may help solve your problem:

**LINK**

John

[Michael GilliganParticipant @michaelgilligan61133]

Posted by WorkshopPete on 18/05/2020 08:19:40:

[…]

Another thing does anyone know why the hole on a slitting saw is slightly eccentric? they all seem to be this way and its not the arbor.

Peter

.

Poor quality assurance

… They are not meant to be that way.

MichaelG.

.

Ref: https://www.model-engineer.co.uk/forums/postings.asp?th=142966

Edited By Michael Gilligan on 18/05/2020 09:00:03

[WorkshopPeteParticipant @workshoppete]

Thanks John

That is very interesting I have always thought Diamond for carbide and CBN for HSS. The one problem I have found with diamond dish wheels is the only one surface is coated normally the flat face where for my application I would like the angled face also to be coated.

Peter

[John BaronParticipant @johnbaron31275]

Hi Guys,

The eccentricity is caused by the wear on the grinding wheel as it is moved in and out of each tooth as it goes around the blade. It also gets worse as the blade is resharpened.

[JasonBModerator @jasonb]

Could one of the wheels of ARC;s EMG end mill sharpener be put to use, available in CBN

[WorkshopPeteParticipant @workshoppete]

Thanks Jason

Yes but it would work well although a bit expensive since most of the coated surface would not be used only small angled portion.

Peter

[John HinkleyParticipant @johnhinkley26699]

Stefan Gotteswinter has done a YouTube video on sharpening saw blades which is worth watching:

Slitting saw sharpening.

In the latter half he refers to a CBN grinding wheel for gashing the gullet (sounds like a euphemism, but isn't). I haven't watched it for a while, but if he doesn't give details, you could drop him an email to enquire where he got his.

John

P.S.  His method should also alleviate the egg-shaped blade syndrome, too.

Edited By John Hinkley on 18/05/2020 10:32:13

[John HaineParticipant @johnhaine32865]

Could you conceivably sharpen a saw with one of those small diamond-coated needle files? Fiddly but probably quicker than finding a suitable wheel and setting it up.

[roy entwistleParticipant @royentwistle24699]

John Joiners used to sharpen and set wood saws by hand so I think a diamond needle file would do at a pinch

[Clive HartlandParticipant @clivehartland94829]

I do mine with a needle file, I first dress off all the teeth so they are the same hieght and then using a saw set, work each tooth, one left, and the next right. Then I start filing observing the cut so both edges work on each tooth.

[BazParticipant @baz89810]

Don’t really see why you cannot use diamond on HSS. I know the reasons why you should not, I worked in R&D for a Diamond tool company for many years, but for the amount we are doing compared to industry, does it really matter?

[Martin ConnellyParticipant @martinconnelly55370]

You want something like this, don't know how much or where to get one.

Martin C

[John RutzenParticipant @johnrutzen76569]

I have a question about slitting saws. I have several from different sources over the years and have never had one that cut evenly. They all seem to be eccentric. I've used them on different arbors and in different machines but it doesn't make any difference.

[speelwerkParticipant @speelwerk]

As far as I can see you need shape 11V9 **LINK** . Centre Abrasifs **LINK** sells them. They can be very helpfull and once made for me a small series of grinding stones for very little money but Google gives also other suppliers for that shape. Niko.

Edited By speelwerk on 18/05/2020 12:01:46

[Michael GilliganParticipant @michaelgilligan61133]

Posted by John Rutzen on 18/05/2020 11:47:06:

I have a question about slitting saws. I have several from different sources over the years and have never had one that cut evenly. They all seem to be eccentric. I've used them on different arbors and in different machines but it doesn't make any difference.

.

So what’s the question, John ?

… and did my earlier post not effectively answer it ?

Sorry but I’m rather bewildered.

MichaelG.

[AdrianRParticipant @adrianr18614]

I found 11V9 CBN wheels on ebay la-877109388934&abcId=1139126&merchantid=118974502&gclid=CjwKCAjw5Ij2BRBdEiwA0Frc9fM9qBPXTHmGhGxv6yJTxar1F0IVUi6GPPoUSGOaaUh3sD3Q4_TwyhoCPKAQAvD_BwE”>https://www.ebay.co.uk/i/174264707109?chn=ps&var=473272588092&norover=1&mkevt=1&mkrid=710-134428-41853-0&mkcid=2&itemid=473272588092_174264707109&targetid=877109388934&device=c&mktype=pla&googleloc=9041085&campaignid=9794971188&mkgroupid=98649237823&rlsatarget=aud-629407025185la-877109388934&abcId=1139126&merchantid=118974502&gclid=CjwKCAjw5Ij2BRBdEiwA0Frc9fM9qBPXTHmGhGxv6yJTxar1F0IVUi6GPPoUSGOaaUh3sD3Q4_TwyhoCPKAQAvD_BwE

[John RutzenParticipant @johnrutzen76569]

The question is why are they eccentric, even new ones? Do other people find that they run true? They are not visibly eccentric , but they don't cut evenly.

[AdrianRParticipant @adrianr18614]

My saws don,t run true and ones I have seen on youTube also dont. I have always assumed it was a combination of the arbour and taper.

But to cut evenly all the way round you would need a constant feed and the saw to be totally true. The slightest variation would be noticeable.

I guess the way to know if it is the saw or arbour, is to mark which side of the saw is touching first then turn it 180 degrees. If it still touches first in the same place it is the saw, if not it is the arbour.

Adrian

[SillyOldDufferModerator @sillyoldduffer]

Not sure I exactly agree with Michael's suggestion it's poor quality control, I suspect it's more value engineering because some teeth being a bit longer than others doesn't matter much in practice. I like the idea it's because the wheel that grinds the teeth gradually wears as it goes round the circumference so the smallest tooth ends up next to the biggest, clunk.

Martindale Saws quote a standard diameter tolerance of ±0.005" whatever the size of saw, which isn't exactly super-accurate. However, the more important thickness tolerance is ten times better at ±0.0005".

Martindale say 'Closer tolerances available at additional cost.' – Price on Application always makes me nervous – II wonder how much they are? Ordinary HSS Martindale saws aren't cheap – about $70 each.

As a challenge, anyone care to measure how far out a few typical saws are? I think being 5 thou out would explain why all mine throb as they cut.

Dave

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