# parting tool?



## Firstgear (Mar 13, 2019)

anyone have a good suggestion for a parting tool?  I have a PM 1440GS with BXA tool post.....


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## jdedmon91 (Mar 13, 2019)

Firstgear said:


> anyone have a good suggestion for a parting tool? I have a PM 1440GS with BXA tool post.....



I made my holder so it would be stiffer. Here is how I did it 





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## stupoty (Mar 13, 2019)

I have one like this, it's amazing.

SPB32-3 32mm Cut Off Blade with 25mm Blade Holder 









						SPB32-3 32mm Cut Off Blade with 25mm Blade Holder and 10pcs ZQMX3N11-1E SP300 In | eBay
					

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I use it on a 13" lathe in a 2 way tool post.  Steel and brass it loves, aluminum not so much, but the inserts arn't listed as good for aluminium so I guess thats why, I think a lot of WD40 or similar would make it ok on aluminuim perhaps.

Stuart


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## davidpbest (Mar 13, 2019)

I work on a PM1340GT, and have about 10 different parting tools - from simple HSS blades to expensive indexable tools.  Which tool I pick has a lot to do with the material I'm going to cut and how deeply, and how wide I can get away with.   It's also extremely important that the tool is exactly on spindle centerline, and is precisely perpendicular to the CL of the spindle.   The more rigid the setup the better - so get your compound back over the CL of the cross slide and lock everything down.   Beyond that, over feeding the tool, and lack of continuous luberication are the next most likely culprets for parting failures.  Unless I'm doing tapers or threading, I will replace the compound with my shop-made solid tool post which I has done wonders to improve parting off operations and surface finish in general.  The solid tool post is a variant on what Robin Renzetti and Stefan Gotteswinter covered on their YouTube channels and my build is covered here:  https://flic.kr/s/aHsm1cKjPB

For aluminum, I will often reach for a HSS blade in an Aloris BXA-71 blade holder.  The cutoff blace is super easy to shapen on a bench grinder, and the #71 holder has a horizontal rather than inclined reference surface for the blade so you don't loose center height when the blade is repositioned or sharpened in the tool holder.   I will often swap the HSS blade out for a cheap insert holder or brazed carbide blade for mild steel.

For more challenging metals (I do a lot of 316 SS), my favorite/go-to parting tool is the Seco Parting tool holder CFZR 0752802DRBJET. 

This is it on MSC:   https://www.mscdirect.com/product/details/51482339?rItem=51482339

This is the insert it takes on MSC:  https://www.mscdirect.com/product/details/51487478?rItem=51487478

Keith Fenner clued me in on this parting tool, and although expensive, it has proven to be the most reliable for difficult materials.   It does require a 3/4" holder, which Precision Matthews sells for BXA mounts (most BXA are limited to 1/2" or 5/8").   

Hope this helps.


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## darkzero (Mar 13, 2019)

I'm not a big fan of the common GTN/GTL/GTR inserts for parting blades. I love my Manchester Separator & Nikcole Mini Systems parting & grooving tools. I use the old Manchester tools the most. Very sharp, nice groove on the center of the insert so they fold the chip to help evacuate easy, & they last forever. Parts Ti 6-4 like butter too. Manchester was bought out by Kennametal years ago but the Separator tools can still be purchased under the Kennametal & Widia brands.

My favorite parting tool is the bandsaw.  I rarely use a parting blade. Whatever exceeds the capacity of my Manchester tools I use the bandsaw.


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## dpb (Mar 14, 2019)

I use a .125” T shaped HSS tool and holder from Shars.  I leave it about 1” out, I don’t adjust it for the part diameter.  I part steel at 90 rpm, aluminum at 250.  Both with the feed set at approx .010” / rev, so an actual feed of about .005” / rev.  Lathe is a 1440GT.
I have parted 303, 304, 6061, 316, 416, 4140, brass, UHMW, and mystery metal, in diameters up to 2”.  I always use power feed.
I have never had a single problem.  I’m not an old hand, but I’ve made several hundred parting cuts, I’d estimate 300-500.
I sharpen the tool when it no longer feels quite as sharp, maybe 4 times now.
Perhaps my time is coming, but all the parting woes are a little mysterious to me.


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## mmcmdl (Mar 14, 2019)

I used many Iscar insert parting tools in the past with no problems .


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## Tom1948 (Mar 14, 2019)

I used to have a hard time parting as well. Watch Joe PI'S video and take his advice as I did. I now have no problem in parting. Alot of it has to do with the setup and getting everything aligned


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## jdedmon91 (Mar 14, 2019)

mmcmdl said:


> I used many Iscar insert parting tools in the past with no problems .



The tool I made was a copy of the blocks available I felt that if it was one piece mounted to the BXA that would increase the strength of the cut off tool. 

I use the GTN type inserts for cut off and it works well for me. 


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## parshal (Mar 14, 2019)

dpb said:


> I use a .125” T shaped HSS tool and holder from Shars.  I leave it about 1” out, I don’t adjust it for the part diameter. ...
> ... I’m not an old hand, but I’ve made several hundred parting cuts, I’d estimate 300-500.
> I sharpen the tool when it no longer feels quite as sharp, maybe 4 times now.
> *Perhaps my time is coming*, but all the parting woes are a little mysterious to me.



Everything you said that I quoted above mirrors my experience to a T.  I have experienced a couple issues but believe it's because I fed too fast.  The part I made bold is what I'm waiting for.  LOL.  I'm looking at all the tools people have posted just see what other options are out there since I've only used HSS blades.


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## mmcmdl (Mar 14, 2019)

Iscar , Kennemetal top notch , Valenite Val Groove , Dorian Slot Grip , Thin bit is what I have in the arsenal . Which ones used depends on the jobs being performed .


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## mmcmdl (Mar 14, 2019)

parshal said:


> Everything you said that I quoted above mirrors my experience to a T. I have experienced a couple issues but believe it's because I fed too fast. The part I made bold is what I'm waiting for. LOL. I'm looking at all the tools people have posted just see what other options are out there since I've only used HSS blades.



Parting tools are like a dog , ya gotta feed them . If you rub the edge off they won't cut . I can only speak for lathes such as the HLV-Hs up to 60" diameters . Not quite sure what these smaller lathes can handle . I may just find out in the near future . If you're running a manual lathe , you're losing CSS while feeding in . It's just a fact of the trade and machine . CNCs are parting at 5000rpm and above .


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## Djl338 (Mar 15, 2019)

stupoty said:


> I have one like this, it's amazing.
> 
> SPB32-3 32mm Cut Off Blade with 25mm Blade Holder
> 
> ...


Stuart, what sets this parting tool apart from the other designs, It looks very stout, what do you like about it?
Thanks
David


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## stupoty (Mar 15, 2019)

Djl338 said:


> Stuart, what sets this parting tool apart from the other designs, It looks very stout, what do you like about it?
> Thanks
> David



I got the 32mm tall blade as a lot of people seem to be saying that it was more rigid than the 26mm (i think thats the next size down)  The holder is also a massive piece of steel which helps a lot, it's 3mm wide insert, I did consider the 2mm parting blades but was concerned it would be to floppy.

I've machined the base to fit strait into my tool post at center height, so it's real easy to set up.

When I have had an issue the insert has kind of fractured apart quite calmly and not caused any damage.

I mostly stay away from insert tooling due to cost concerns but the generic tips seem to be fine for mild steel and brass, the iscar ones would have to be amazing to make the extra cost worth it for me.

I've got a new HSS holder which I havn't actualy used much yet so I will try and do some parting tomorow and get back with my experiences 

Stuart


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## Djl338 (Mar 15, 2019)

stupoty said:


> I got the 32mm tall blade as a lot of people seem to be saying that it was more rigid than the 26mm (i think thats the next size down)  The holder is also a massive piece of steel which helps a lot, it's 3mm wide insert, I did consider the 2mm parting blades but was concerned it would be to floppy.
> 
> I've machined the base to fit strait into my tool post at center height, so it's real easy to set up.
> 
> ...


Thanks, I have an hss tool and a smaller insert tool, but that tool looks like a very stable cutter. I may need to pick one up!
David


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## stupoty (Mar 17, 2019)

I did some parting using my HSS blade holder , I've got this one. It did a nice clean job on some 1" OD aluminium with a 5mm hole in the middle. I used my regular cutting lube.


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## Firstgear (Mar 17, 2019)

I had bought one of these for parting, it seemed to do well cutting initially 12L14 5/16” hex bars.  In every case it started out well, but after getting about 1/8” or so into the part, the insert would push back and then shatter.  I put oil on the part to start.

I made sure that the cutter was perpendicular to the part.  But in every case, 3 times now, the cutter shattered.  Hence my questions....

I read on McMaster Carr, at least this is what I thought I read was that these types of inserts were only good for about 1.5 the insert in depth capability.  Am I understanding this correctly, it’s really a grove making tool?


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## stupoty (Mar 17, 2019)

The deepest I have parted with the GTN3 inserts is 2" square hot roll bar stock with 1.25" hole in center  , 2" OD round cold roll with small (maybe 8mm) center hole.

Theirs good clearance from the side of the inserts to the holder so I havn't had it rub during cutting.

Stuart


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## Mark Needham (Mar 18, 2019)

Like my missus, parting sneaks up and bites me on the arse, more often than not. Some days, good as gold...others.....?
Tried everything, a new wife, girlfriends, brown and white, normal and upside down.
Best way is manually doing it, with the bandsaw.


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## bretthl (Mar 18, 2019)

I've had good luck so far with this one in hot roll and 4130.  I decided to purchase it after a couple of unpleasant experiences with HSS parting blade in steel.  I like it because the blade is smaller than the groove cut by the insert.  I'm sure I will destroy it sooner or later.  Set up with any parting tool is critical.


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## stupoty (Mar 18, 2019)

bretthl said:


> after a couple of unpleasant experiences with HSS parting blade in steel.




Did they explode ? I've had a few literaly shatter into many flying pieces, always good to un nerve one a little 

Stuart


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## stupoty (Mar 18, 2019)

Mark Needham said:


> Best way is manually doing it, with the bandsaw.



Definitely that can be easier but it is nice to be able to part off.  I think finding the sweet spot for your lath and tool is key then it becomes much less scary.



Stuart


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## bretthl (Mar 18, 2019)

stupoty said:


> Did they explode ? I've had a few literaly shatter into many flying pieces, always good to un nerve one a little
> 
> Stuart



Exactly!  I blame it on my setup though.  Nothing like parting at 90 rpm and having the blade grab the work.  I swear no matter how fast you think you are you will never hit the ESD before the blade explodes.  However ... parting is going better with the GTN setup.  Bandsaw is my first choice when practical.


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## Firstgear (Mar 18, 2019)

bretthl said:


> I've had good luck so far with this one in hot roll and 4130.  I decided to purchase it after a couple of unpleasant experiences with HSS parting blade in steel.  I like it because the blade is smaller than the groove cut by the insert.  I'm sure I will destroy it sooner or later.  Set up with any parting tool is critical.
> 
> View attachment 290709


I ordered a set up like this....I am trying a couple of different approaches.


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## wildo (Jun 11, 2019)

darkzero said:


> I'm not a big fan of the common GTN/GTL/GTR inserts for parting blades. I love my Manchester Separator & Nikcole Mini Systems parting & grooving tools. I use the old Manchester tools the most. Very sharp, nice groove on the center of the insert so they fold the chip to help evacuate easy, & they last forever. Parts Ti 6-4 like butter too. Manchester was bought out by Kennametal years ago but the Separator tools can still be purchased under the Kennametal & Widia brands.
> 
> My favorite parting tool is the bandsaw.  I rarely use a parting blade. Whatever exceeds the capacity of my Manchester tools I use the bandsaw.
> 
> ...



Can you indicate when the holder number is on those Manchester holders? I can't seem to find that style.
[EDIT]- Also, what Separator insert are you using in which you have so much success in titanium? That is specifically my target material that I need to part.


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## Winegrower (Jun 11, 2019)

I used to have negligible success parting until I did two things...got a cutoff insert holder like Stupoty and bought a really rigid beefy lathe.   So far, no problems.


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## NortonDommi (Jun 11, 2019)

Here's mine made from scrap to run a 32 mm blade upside down. The other aim was to get the blade as close to the pivot of the toolpost as possible.
Slot was cut on the mill when cutting dovetails and then cleaned up in place on the lathe.  Can part off under power at turning speed.


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## Firstgear (Jun 11, 2019)

This has become my favored parting tool.....


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## ThinWoodsman (Jun 11, 2019)

Firstgear said:


> This has become my favored parting tool.....


Agreed. The insert is a little wide though, I might try a holder with thinner ones if I can set aside the time to wade through the gajillion different insert types.


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## savarin (Jun 11, 2019)

My parting woes dissipated once I replaced the top slide with a solid plinth to hold my axa qctp.
I use hss "T" shaped blades, always check its on centre but just eyeball the 90'.


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## BGHansen (Jun 11, 2019)

I probably use a GTN-2 and 3 the most.  Also use a T-shaped HSS 5/8" tall blade and MGMN200/300 inserts.  I've had the same luck you did with the MGMN though it depends on the material (had good luck with aluminum and brass).

I go to back gear when parting steel with the GTN-2 or 3, had good luck with them.  Also good results with stainless and drill rod.

I can't recall having a problem with the HSS with any material.  I follow Tom's Technique's recommendation of sharpening the tool with each use.

Bruce


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## jdedmon91 (Jun 13, 2019)

NortonDommi said:


> Here's mine made from scrap to run a 32 mm blade upside down. The other aim was to get the blade as close to the pivot of the toolpost as possible.
> Slot was cut on the mill when cutting dovetails and then cleaned up in place on the lathe. Can part off under power at turning speed.



I like that set up. I remade my parting setup so my block and GTN holder is one piece. It is thicker than yours however it has worked well 







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