Conversational Lathe Parting

[sagreen]

I've converted a Grizzly G0602 lathe to run under pathpilot. Having some problems with parting. I have the tool set to as close to the exact center as I can get it, but as the lathe feeds to the center it seems like its trying to crawl under the stock. Tool is square to chuck within a couple thou over the length of the tool. Using what I would consider light cuts as in the attached picture.

What are others that are using an 8L using for feeds and speeds in 6061 aluminum. Am I running too fast? should I take a deeper cut? etc... I am not running coolant.



@ 37:05 in this video the operator is taking a LOT more aggressive cut than I am and its blasting through the part without coolant.

Thanks!
Scott...

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[mountaindew]

I've converted a Grizzly G0602 lathe to run under pathpilot. Having some problems with parting. I have the tool set to as close to the exact center as I can get it, but as the lathe feeds to the center it seems like its trying to crawl under the stock. Tool is square to chuck within a couple thou over the length of the tool. Using what I would consider light cuts as in the attached picture.

What are others that are using an 8L using for feeds and speeds in 6061 aluminum. Am I running too fast? should I take a deeper cut? etc... I am not running coolant.

@ 37:05 in this video the operator is taking a LOT more aggressive cut than I am and its blasting through the part without coolant.

Thanks!
Scott...

300 sfm is pretty fast I do around 100 but could go faster
I would look at feed per Rev and make it less until it works . Then peck depth can be reduced to allow chips to clear. all the rest looks OK alum should be easy to part. Maybe some lube applied with a brush will help
What kind of tool? I use insert type parting tools. Spindle rigidity will effect how well this works also

[vmax549]

It looks as if they are cutting 7075 alum which cuts much better and cleaner than 6061 and it also depends on what temper your 6061 is T0 >> T6. IF your tool is nodding under the centerline it could be your machine or tool setup is flexable OR the alum is soft and gummy or the tool itself is wrong for alum.

It could be a lot of things, (;-) TP

[sagreen]

300 sfm is pretty fast I do around 100 but could go faster
I would look at feed per Rev and make it less until it works . Then peck depth can be reduced to allow chips to clear. all the rest looks OK alum should be easy to part. Maybe some lube applied with a brush will help
What kind of tool? I use insert type parting tools. Spindle rigidity will effect how well this works also

This is the tool set I'm using. Its a carbide insert.

https://www.grizzly.com/products/gri...set-3-8/t10293

Scott...

[shred]

I've converted a Grizzly G0602 lathe to run under pathpilot. Having some problems with parting. I have the tool set to as close to the exact center as I can get it, but as the lathe feeds to the center it seems like its trying to crawl under the stock. Tool is square to chuck within a couple thou over the length of the tool. Using what I would consider light cuts as in the attached picture.

@ 37:05 in this video the operator is taking a LOT more aggressive cut than I am and its blasting through the part without coolant.

Thanks!
Scott...

The 15L in the video is a much beefier machine than a G0602, so not very comparable.
It also looks like your parting tool has a flat face versus the convex one in the video that 'folds up' the chip as it cuts so you can't push it as hard.

All that said, the cuts don't look way off base, although 0.01" peck is tiny and the SFM is high. You have CSS working properly on the spindle? Pecking every 10 turns of the stock is going to do some beating on the speed changes.

[mountaindew]

As shred mentions the tool has a flat face and the chip just rolls up. Why I mentioned maybe backing off the peck a little to get chips to clear.
I have never used any of the lathe conversation setup screens so it was hard to tell what I was looking at! Also the conversation code can act much different then my cam code doing what appears to be the same thing with the same settings
Do you have an encoder controlling the feed and speed? The motor will pull or slow down when parting and the feed needs to change with the reduced sfm speed?
You can also use the feed and speed sliders on screen to back off your settings and maybe find a spot it starts to work better!

I have a 10x32 precision mathews manual lathe and it has what appears to be a rigidity problem when parting off material. I think the problem is the chuck and or the chuck to spindle connection. Works fine for all other lathe work but struggles to part material off!

The 8l lathe using 5c collets has very little problem parting off most the materials I use like cold roll, s.s., aluminum, brass, bronze. I have not tried it with a chuck and the added stick out or hang over that would add .

[vmax549]

It would really depend on exactly what the insert is. For general alum I use uncoated highly polished inserts with a decent amount of front and back rake. Some coatings and alum do not get along well An insert with a flat top and face does not always do well in Alum as it tends to rub more than cut. IF you have a piece of HSS laying around grind you up a tool and try it . I am thinking you have the wrong insert type for softer alum. 6061.

Just a thought, and I could be wrong (;-) TP

[mountaindew]

It would really depend on exactly what the insert is. For general alum I use uncoated highly polished inserts with a decent amount of front and back rake. Some coatings and alum do not get along well An insert with a flat top and face does not always do well in Alum as it tends to rub more than cut. IF you have a piece of HSS laying around grind you up a tool and try it . I am thinking you have the wrong insert type for softer alum. 6061.

Just a thought, and I could be wrong (;-) TP

I would buy another brand. I have not found much from grizzly that ever worked very well or for very long.
I could write a paragraph about bad experiences with most things I have purchased from them. In fact they got put on my no buy list after my last purchase of dust vac hose. I was not happy at all and the stuff is in a box in my shed. Had to replace it all. Simple stuff that should work but it was junk. Lol

[toyshop]

look up inverted parting or upside down parting tool. Supposedly it tightens up the cross slide by lifting against the dovetails instead of pushing down.
Use shortest tool protrusion also. If going very deep you need coolant. The part will heat up and expand away from the chuck and start pinching the tool.. HSS can cut freer but the alignment is critical due to the lack of side clearance past the cut edge.

Dave

[mountaindew]

look up inverted parting or upside down parting tool. Supposedly it tightens up the cross slide by lifting against the dovetails instead of pushing down.
Use shortest tool protrusion also. If going very deep you need coolant. The part will heat up and expand away from the chuck and start pinching the tool.. HSS can cut freer but the alignment is critical due to the lack of side clearance past the cut edge.

Dave

This could also be the problem. I often assume the machine is tight and adjusted.

[toyshop]

Not everything Grizzley sells is junk but always a compromise to the market segment. I have a 14-40 that is shipped at 2800 lbs and is just as good as the 1340 DoAll (harrison) I used at work. They didn't sell that model long and I did go see it before purchase.
At the time I couldn't find anything used that wasn't clapped out.

I would have preferred something like a Colchester 15" x 60+ (used them before), but not in the price or space I had. I hear a lot of buy old American iron, but there is a reason they are being sold, sometimes it cause they are worn out. I did a lot of work on both DoAll s and L&S. to keep them running and tuned up. I really didn't want another project machine. My Tree mill was enough.

Dave

[mountaindew]

Not everything Grizzley sells is junk but always a compromise to the market segment. I have a 14-40 that is shipped at 2800 lbs and is just as good as the 1340 DoAll (harrison) I used at work. They didn't sell that model long and I did go see it before purchase.
At the time I couldn't find anything used that wasn't clapped out.

I would have preferred something like a Colchester 15" x 60+ (used them before), but not in the price or space I had. I hear a lot of buy old American iron, but there is a reason they are being sold, sometimes it cause they are worn out. I did a lot of work on both DoAll s and L&S. to keep them running and tuned up. I really didn't want another project machine. My Tree mill was enough.

Dave

For the most part I agree. I do have a sander and buffer from grizz that did work for about 2 years before they had to be tossed in the shed.
they were cheaper models and not up to my use cycle.
in short they just pissed me off with the dust vac hose. It had a picture that made it look like good stuff. but when deliver it was collapsed down in a small box. I was like oh no this stuff wont work it will always want to collapse during use and also so much vac drag from all the bellows in the material that the dust vac system no loner even worked. Replaced it with hose that is flexable but smooth on inside and vac system was back working perfect. I complained to grizz and posted a review of this product so others would not buy and get stuck with it and it was deleted.

back on subject of parting off. I had material move slightly in collet " material flex" I was parting - grooving 1.5 inches out from spindle and it climbed under and stuck just like the problem stated above.
So any movement in material at all, can also cause this type of op to fail.

[gerritv]

I have a King KC1022, essentially a G0602. I part 6061 with an Aliexpress 2mm wide parting insert at 120 sfm (approx).
I found my spindle bearings needed tightening, and I replace the compound with a solid tool post mount. As a result, no more dipiing of the tool.

Presently using an ELS on the lathe but am considering trying PathPilot as well. Already using it on my shop built gantry router/mill.

[sagreen]

Presently using an ELS on the lathe but am considering trying PathPilot as well. Already using it on my shop built gantry router/mill.

The conversion is not terribly hard. Glad to donate the files that I built for my lathe.

Scott...

[sagreen]

Ok, problem solved...

Turns out the entire problem was because there was a loose bolt holding the front retention plate to the saddle. You have to remove the entire top side of the carriage to get to it as it screws down from the top, under the cross slide. I was taking it all apart to mill those plates and found this bolt loose. It was less than finger tight. Effectively no plate on that side. This was letting the carriage float up off of the ways. Glad I found the problem without having to mill and add the grub screws.

Scott...