Slitting Saw Holder

[Johan CrousParticipant @johancrous15881]

I have ordered 2 slitsaw blades of 100 x 22 x 1.2 mm.

While I am waiting for them to arrive. I would like to know what is the best way to make a holder for them.
I can make one with a straight shank to be gripped in my lathe chuck and collet holders, or I may fit a morse taper shank, but them I have to remove the lathe chuck each time I want to use it.

What is the easiest way forward? (How can I prevent the blade from running off-centre? I see that this is aparently a common occurance)

[Johan CrousParticipant @johancrous15881]

[NobbyParticipant @nobby]

HI
If you use a morse taper holder you would need to use a draw bar to tighten up as it my come out when cutting To keep it true and not running off turn the locating dia to a good fit to the bore size of the cutter. I suppose a straight shank would be the answer . Will it be for the lathe & a milling machine ?
The locating fitting  depth should be just under the 1.2 thickness of the cutter so it will be clamped nice and tight .

Nobby

 

 

Edited By Nobby on 09/12/2012 17:48:03

Edited By Nobby on 09/12/2012 17:49:14

[NJHParticipant @njh]

Johan

My personal preference is for a straight shank to hold in a chuck. I don't like to take the risk of a saw in a MT holder jamming up with consequent risk of damage to the MT socket.

Excentricity on saws? – see other postings here but I don't know that it matters that much as long as it is not too great – just go steadily.

N

Edited By NJH on 09/12/2012 17:50:20

[Peter TuckerParticipant @petertucker86088]

Hi Johan,

If you are keen make both holders, just be sure to include a draw bar thread in the back of the MT shank.

A holder made in the lath all at one setting will be concentric therefore the blade should run on centre, however many (most ?) blades are made slightly off centre.

Good luck.

Peter.

[Sub MandrelParticipant @submandrel]

If you don't put a key in the holder and just rely on a friction grip, then if the saw jams it will spin harmlessly in the holder, not scour the shank or the MT socket.

Neil

[speelwerkParticipant @speelwerk]

You can made a straight shank with a centre on each end, if you are in a hurry you can chuck and if want to be more accurate you can place it between centres, no need to make a morse taper shank.

Niko.

[MICHAEL WILLIAMSParticipant @michaelwilliams41215]

For use specifically in a lathe what I do now is to use a freshly turned spigot each time . Mount bar firmly in whatever chuck or collet is currently fitted to lathe , turn seat for saw , thread for nut – 90 seconds max – done . Saw is guaranteed to run true .

If saw is a long way from chuck then centre bar end for taistock support .

 

 

Edited By MICHAEL WILLIAMS on 09/12/2012 20:32:37

[chris jParticipant @chrisj]

Posted by MICHAEL WILLIAMS on 09/12/2012 20:24:13:

For use specifically in a lathe what I do now is to use a freshly turned spigot each time . Mount bar firmly in whatever chuck or collet is currently fitted to lathe , turn seat for saw , thread for nut – 90 seconds max – done . Saw is guaranteed to run true .

If saw is a long way from chuck then centre bar end for taistock support .

Edited By MICHAEL WILLIAMS on 09/12/2012 20:32:37

You must have a lot of metal (and nuts) hanging around.

[Boiler BriParticipant @boilerbri]

I want to cut some 4" x 1/4" brass angle with a 1.5mm x4" slitting saw. Can i cut throught the 1/4" thickness in one go with a slow speed?

Bri

[Russell EberhardtParticipant @russelleberhardt48058]

Posted by Boiler Bri on 10/01/2014 06:44:02:

I want to cut some 4" x 1/4" brass angle with a 1.5mm x4" slitting saw. Can i cut throught the 1/4" thickness in one go with a slow speed?

Yes, I would use about 250 rpm for brass and a nice gentle feed. Make sure the set-up is rigid and that the cut won't close up on the saw at the end.

Russell.

[Anonymous]

Posted by Boiler Bri on 10/01/2014 06:44:02:

I want to cut some 4" x 1/4" brass angle with a 1.5mm x4" slitting saw. Can i cut throught the 1/4" thickness in one go with a slow speed?

Bri

The answer is a yes but! In other words yes you can do it, but you'll need a rigid set up. Here's a slitting saw taking a 1/2" cut in cast iron:

Contrary to popular opinion I always use keys when taking serious cuts with slitting saws.

Regards,

Andrew

PS: There is a fundamental flaw in the set up shown, that resulted in a shattered blade; can anyone spot it?

[DMBParticipant @dmb]

Andrew,
The blade appears to have cut through most of the job but the teeth apparently emerging from the work are pointing UP.This means that the saw has been run wrong way. If it was a milling cutter this would be called climb milling.
John

[Brian WoodParticipant @brianwood45127]

Hello Andrew and John,

John. I disagree with you, climb milling is when the cutter is trying to 'drag' the work into itself as would be the case if the blade in this example was mounted the other way round. This arrangement is not prone to that.

Andrew. I can't see a fault unless the cut closed up behind the blade and grabbed it, but that woulldn't be obvious.

A stop block at the foot of the job would ensure the work could not move with cutting forces; is that it?

Brian

[Martin WParticipant @martinw]

Andrew

Looking closely at the photo the 'off cut' section of the casting appears to be resting/bearing down onto the table. Was this then taking some of the clamping load and towards the end of the process caused the casting to break resulting in blade pinch or worse still, if indeed it did fail, it allowed the entire job to move due to reduce holding force? The only other thing, not that I think you would miss it, did the saw arbor foul one of the hold down studs as the depth of the cut was increased.

Cheers

Martin

Edited By Martin W on 10/01/2014 10:53:54

[IanTParticipant @iant]

Did the bit you were cutting off – fly off to the left and hit something?

IanT

[Anonymous]

The slitting saw was running clockwise, as seen from the arbor support, and traversing right to left, so it was conventional milling. The table does have a climbing milling knob, which is basically a backlash adjuster. I'm happy climb milling on the vertical and CNC mills, but I haven't had the nerve to try it on the horizontal yet.

I think that Martin has come closest to identifying the issue. The casting is partially hollow underneath as can be seen by the body of the casting sitting above the table, even although the casting is in fact bolted directly to the table. The cut was carefully lined up with the central T-slot. The intention was to cut most of the way through, leaving a couple of 1/4" sections to be cut through with a hacksaw. Unfortunately I was a bit ambitious on the depth of cut and the two parts of the casting separated. So the slitting saw was left with a fair depth of cut, but suddenly unsupported on one side. So it tried to modify its form into a cone, and shattered. I picked up pieces of the cutter from both sides of the workshop, a good 16 feet apart. That's why I always wear proper safety googles when machining. Had I clamped both halves of the casting it probably wouldn't have happened.

Regards,

Andrew

[mechman48Participant @mechman48]

I tend to agree with Andrew / Martin; the 'offcut' side should have been clamped to prevent any movement therefor allowing 'pinch' or 'break off' which would damage the cutter. It also looks like the arbour maybe catching the rear hold down stud (camera angle? ). Assuming the casting ( looking at the pic ) has a hollow through it I would have looked at clamping it through the centre to the table, without interfering with the arbour, ensuring the clamping forces were directed from the centre of the casting outward plus end stops, as it is the clamps could be pulling down on the sides & introducing some bending forces to the middle, can't make out if the back side on the table was machined?.

George

Blast! Martin has told us whilst I was typing.

Edited By mechman48 on 10/01/2014 12:26:18

[Boiler BriParticipant @boilerbri]

Thank you for the advice. I will give it a go tomorrow and let you know how i get on.

Bri

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