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Has anyone tried the modification to a parting off tool shown in WINKY'S youtube video

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TQA222

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#1
I am buying a 7 x 12 HF mini lathe and have become aware that parting off can be a problem. There is a youtube video which shows a simple method of stiffening the tool in the toolpost.

Winky video clip

Has anyone tried this on a mini lathe and did it work?

He used a British cut off tool called an ARC QA 060-325-20802 [ see second clip when he goes down to a 2 mm wide tip. ] Does anyone in the USA stock this tool.
 

BaronJ

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#2
Hi Guys,

The major problem that is shown in that video is that the parting tool is above center !
Also the whole top slide is moving not just the tool holder. By adding the support post he is simply stiffening the tool. He would gain the same benefit from simply tightening the gibs.

I also noticed that he didn't use lubricant until the last cut he made when using the stiffening post under the tool. I also noticed that his top slide doesn't have any provision for mounting a rear toolpost that could be used to support a parting tool. I have and prefer to part from the back. I also use a 1/16" thick USA made parting blade.
09072015-06.JPG

This is my rear tool post and parting off blade.
25062015-012.JPG

This is the etched data on the side of the blade.
 

ddickey

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#3
Same here Baron. I don't have T-slots but I made it work.
I wonder how wide those insert blades are.
 

BaronJ

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#4
Hi Dickey,

Usually 2 to 4 mm wide in increments. But I think that they are way too expensive from a hobbyist point of view. They may be cheaper on your side of the pond. Also the holders don't like any side load ! They bend and the insert comes out.
 

ddickey

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#5
I've never used one. My US made T-type blades work great.
 

mikey

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#6
Inserted carbide parting tools work really well if you have the speed and rigidity to use them. Cost is not too bad because the inserts last a long time. I have an Aloris parting tool that works without issues but the insert is 1/8" thick and I don't use it much. HSS works much better for me in just about every case.

For a little 7X mini-lathe, inserted parting tools may not be the best option because they lack the power, speed and rigidity to use them well. A good HSS tool will work better.
 

BaronJ

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#7
Hi Dickey,

I've seen those, but never had one to play with. What are they like, what do you think of them.
 

ddickey

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#8
This is the place I got mine.
They need to be set perfect on center like anything else.
I think the price is reasonable. I also made my own holders for them.
Overall I think they are great. I have not used a lot of different one though so really nothing to compare too. I'm perfectly happy with them.
https://www.sommatool.com/catalog/cutting.tools/ttype_cutoff_blades.asp
 

BaronJ

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#9
Thanks for that info Dickey, I'll look into those.
 

Dabbler

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#10
THanks for the video link! His solution is very smart - makes a small lathe do its best job! I usually use HSS cutoff tools in my 12X37, but this video may open up cutoff insert tooling for me!

The design is very good, so I can't see why I shouldn't try it!
 

ddickey

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#11
Part two.
 

Dabbler

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#12
The part 2 version is VERY impressive.
 

MarkM

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#13
I don t know if there is any magical tool for parting. Wether it s inserts or hss i think imop. It comes down to the tool geometry, and your speeds and feeds. It s one operation where you can t sway from what s proper maching or it will bite you but get into that area and have a nice shear cut that you can feel if hand feeding. It s a good thing to learn with the hss to understand what tool geometry is rather than buy what works. I think you will find you will always be going back to hss even when working with carbides and understanding how to make tools is a skill you ll need as projects progress.
Don t be shy with your tool. Get in under then back off your presssure once start cutting. Alot make the mistake to baby there entry. Leading edge, rake, hollow ground go find that shear cut!
 

MikeWi

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#14
There's definitely some magic involved to using t-blades (regular) parting tools that I can't learn. I've broken both ends of my parting tool, but my carbide parting tool from Shars has never failed me. That second side was broken just last week. I've been doing this long enough that I though I might have a handle on it. Nope!
 

Tozguy

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#15
The amount of movement of the tool holder in the video before adding the support was exceptional. I suspect that the rigidity of set up could/should be improved not just for parting but for any sort of cutting. For example, the compound slide could be backed away from the work as much as possible and the cross slide moved in an equal amount. This to get the cutting action as close as possible to the two bolts holding the compound to the cross slide and reduce overhang of the set up. The gibs on the compound should be locked tight. The carriage locked tight also.
Then the strut that supports the cut off tool would still be a plus but it would not have to cover up weaknesses elsewhere.
 
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savarin

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#16
I am very firmly convinced that rigidity of the system is the key.
I've removed the top slide and replaced it with a solid plinth.
That alone was like chalk and cheese.
I've just finished scraping in the saddle and cross slide and adding oil grooves plus more gib screws to remove as much backlash and other movement and again the improvement in parting is astounding.
I use a 1/16" "T" blade in an AXA holder and touch up the tip with a fine diamond hone before use.
Yesterday was my first parting job since the adjusting and parting some 19mm stainless and was effortless and some rolls of swarf were tight rolls about 10mm dia.
 
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