# Parting Tool Choice



## Doh!Nut (Oct 22, 2009)

I am trying to choose a new parting tool for my small lathe - its a 7*12 but more robust than the small 7*12's Warco Lathe 

I have used tools like boring bar and these seem to be a good match of Tool / machine / price.
With that background I was looking at getting a new parting off tool.

I have been using a very flimsy parting tool Parting tool

Unsurprisingly I have a lot of chatter and have accepted the need to upgrade 
:thumbsdow

They sell the big blade version Big Blade
I am not too keen on this as the blade is 3/32" (2.4mm) which is wider than I want - relies on cutting blade for stiffness and supporting blade is same width as cutting edge. But it is obviously much stiffer than what I have for a reasonable price.

Or there is this Glanze tool Glanze Small blade
I like this as insert is well supported so looks excelent for deep grooves but It would surely be on the limit (or beyond for parting 1.5" stock (38mm). I cant appear to find the cutting depth limit for this tool.

Or there is this Glanze tool big blade glanze tool. 
It looks to do what I want but is triple the price of the first option :sigh:

Opinions?


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## precisionworks (Oct 22, 2009)

A narrow insert takes less hp & less force, and does a nice job when supported by a rigid holder. General rule is the smaller the machine, the narrower the insert for parting. 

Your first link to the Glanze Small Blade shows a tool identical to what I use for most parting, as the insert support is close & massive. Depth of cut is limited but is enough for most of what I do, and may be enough for what you do. The Glanze Big Blade has unlimited DOC, but support starts to get iffy with longer extension.

In the USA, Carbide Depot carries a bunch of inserts & holders, some of which may be available in the UK http://www.carbidedepot.com/Dynamiclanding.aspx?CategoryID=4281


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## Mirage_Man (Oct 22, 2009)

Here's a thread that might help.

https://www.candlepowerforums.com/threads/215747


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## Doh!Nut (Oct 22, 2009)

Thanks for the advice and links

I think I will go for the Glanze small blade tool.

I does make sense that I should use the best tooling for the most difficult procedure (on a small lathe) 

Nick


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## gadget_lover (Oct 22, 2009)

I use the standard 1/2 inch tall (I think) parting blade with my 7x12 and seldom see any trouble. I part up to 2 inch thick bars of aluminum. It seems like it has better support tha. The Glance model, since it is a solid 1/2 inch thick the full length of the holder. 

The two tricks are:

1) make the edge sharp
2) make the blade absolutely perpendicular to the work
3) include some top rake
4) ensure there is side clearance
5) tighten all Gibs and lock the z axis

ok. 5 things. 

Daniel


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## darkzero (Oct 25, 2009)

Doh!Nut said:


> Or there is this Glanze tool big blade glanze tool.
> It looks to do what I want but is triple the price of the first option :sigh:


 
I have this same parting tool from Glanze except I have the 12mm (1/2") version. I believe the 10mm (3/8") version uses the same blade & both use 2mm inserts. I'm very happy with it & it works great, I'd definitely recommend it. You can buy directly from http://www.chronos.ltd.uk/. I get even better results using Iscar GTN2 IC20 inserts & they seem to last forever. I still use my 1/2" height HSS parting blade alot too though which also works great.


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## kd5ahl (May 12, 2010)

what kind of lathe do you use the 12mm tool on? I'm interested in getting one and am not sure if the tool tip will be too high for a 7x14.

I'll grab the 3/8 shank if it's too tall.

thanks


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## darkzero (May 12, 2010)

kd5ahl said:


> what kind of lathe do you use the 12mm tool on? I'm interested in getting one and am not sure if the tool tip will be too high for a 7x14.
> 
> I'll grab the 3/8 shank if it's too tall.
> 
> thanks


 
I used the 12mm with an 8x14 w/ AXA tool post a slightly milled holders. The 10mm (3/8) would probaby be best for the 7x. Grizzly sells the 10mm version if you are in the US.


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## wquiles (May 13, 2010)

Now-a-days, 9 out of every 10 parting jobs, if I can cut it on the metal band saw, I don't bother with parting on the lathe. I just cut the part in my metal band saw, and then square up/clean up the edge in the lathe. 

Here is an example in a D size Mag right after cutting on the band saw (notice rough edge):







After cleaning the rough edge:






Even though I have enough power and rigidity to cut these tubes in the lathe and save one operation, it is just so much easier and with zero stress to cut them in the metal band saw


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## darkzero (May 13, 2010)

wquiles said:


> Now-a-days, 9 out of every 10 parting jobs, if I can cut it on the metal band saw, I don't bother with parting on the lathe.


 
Guess it really depends on what one is working on. I find myself doing quite the opposite, I use parting operations alot. I only use the bandsaw to shorten stock down to 1-2 feet when I get them in 36" lengths which is not that often. 

Now that I have the larger spindle bore, I just bury the excess stock in the spindle/chuck, turn the part, then part off. I just wish there was a better way as I use one hand to catch the semi finished parted piece to protect any damage to the finish while feeding with the other hand. I guess I could power feed while parting which will free up the other hand for better control but it just seems to risky if a mishap were to occur.


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## PhotonFanatic (May 13, 2010)

If a mishap were to happen, it wouldn't make any difference whether you were power feeding, or feeding manually--there is zero possibility of your reacting quickly enough to prevent the disaster when manually feeding.


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## darkzero (May 13, 2010)

PhotonFanatic said:


> If a mishap were to happen, it wouldn't make any difference whether you were power feeding, or feeding manually--there is zero possibility of your reacting quickly enough to prevent the disaster when manually feeding.


 
Are you suggesting that I try power feeding for parting? :devil:
Maybe in alumn or brass but I would be scared to try with the harder metals.

I would definitely agree regarding not being able to react quickly enough but in my situation I would have to slightly disagree as well.

At times when I have that gut feeling (mostly with steel & times I push the lathe farther than I've tried before) I keep one foot on the foot brake. I feel that the foot brake has saved me a few times from what might have been worse. I have not reacted by pushing the stop switch, disengaging, etc enough times to drill it into my head but stomping on the foot brake is easy & stops everything including braking the spindle.

Now that I read it again I wasn't quite making sense when I said power feeding would free up the other hand for control. Power feeding would free up the other hand but this would only allow that hand to be ready for the stop switch or disengaging the feed lever.

When I'm parting I'm positioned away from the chuck, my right hand is reaching around the tool post to catch the part & my left hand is feeding the cross slide. I'm used to using two hands to give a nice steady feed. In this position I lack control & can't always feed the cross slide smooth & continuously. So I always have to watch & back out to clear chips when needed. Since I'm feeding manually I guess I can better control the cut & compensate as needed. I suppose power feeding would eliminate that as it's feeding at a steady rate & perhaps mostly likely it should be fine just as long as the feed is not to fast & the tool is lined up perfectly. I think in my mind I'm just scared of the tool digging under & the outcome. :duck:


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## gadget_lover (May 13, 2010)

> If a mishap were to happen, it wouldn't make any difference whether you were power feeding, or feeding manually



I have found that I can catch a bad parting operation most of the time before it goes bad. You can feel it when it starts to chatter, bind or dig in. I'm not sure I'd be able to do that with a power feed while parting.

Most of the problems that *I* have when parting are due to failure to do the things that I've posted here. But there's only 4 or 5 things to make sucessful parting routine.

Daniel


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## KC2IXE (May 13, 2010)

I part of constantly, and at sfm rates that would make a lot of people gasp - then again, I have a reason - I actually do some production work - when you are knocking off 100 of the same part, and are for all intents being a human screw machine, the ability to part off, time after time, reliably makes a HUGE difference. With the one really long running job - if I can cut 30 seconds off the cycle time, I'm real happy


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## precisionworks (May 14, 2010)

> I don't bother with parting on the lathe. I just cut the part in my metal band saw


+1

Parting is a tough op, even when the cut is right next to the chuck. Most every type of parting tool, whether HSS blade type or insert type, puts a pretty fragile tool point into the material with zero side clearance ... and often no way for the chip to leave the cut. I part in the lathe when nothing else will work, so I have half as many broken parting tools as most people 



> I actually do some production work ...


Same here, but I precut whenever possible in either the band saw or the cold saw. The band saw (with a length stop) will repeat to under .050", but the cold saw is the real champion, repeating to .005" cut after cut. Most cold sawn parts are cut .030" - .040" long, leaving .015" - .020" to face off each end. Since the cold saw produces a cut surface that looks machined, fifteen to twenty is more than enough.



> I guess I could power feed while parting


The tool sellers will love you 

Power feed does work well on a NC machine that allows constant sfpm. If you watch some of the videos on youtube, you'll see and hear the spindle running slowly at the start of the cut, with spindle rpm increasing as the tool plunges deeper into the part. One of the biggest problems in lathe parting is that the sfpm that is correct for the starting diameter is horridly slow as the tool approaches the middle of the part.


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## 1917 (May 27, 2010)

I think one problem some people have when parting is letting a chip come between the tool and the work piece. The tool feeds into the chip which is rubbing against the turning work. Then snap. If you back the tool out make sure the chips are clear. I parted 100+ 1 1/2" solid titanium not long ago with 1 insert change and no problems. Used slow power feed and 360rpm. The insert might have lasted but I noticed the parts were getting a little hot.


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