ARC NCIH Part Off Blade

Worth a shot to buy and see, though I'm thinking that the Iscar would be a proprietary pattern.

After reading the problems that people have with parting off, I'm thinking of just staying with the Iscar holder and tips. Even though they are expensive, I've never had the slightest problem parting anything with the Sieg C6 lathe and the Iscar holder and tips, honestly its like using a hot knife through butter.

I destroyed a few insert blades doing some testing in the thread linked below but i did find some interesting things out about parting off . I was using the hare and forbes units ( toolmaster ) but i won’t be forking out that amount of cash for a new blade anytime soon - not from them anyway ! I believe Ausee are linked to ARC in some way ? If so i may try their holders and tips .

**LINK**

It looks like a bent flat head screw driver:

Ketan at ARC.

If you are happy with the ISCAR holder, I would suggest that you consider the ISCAR inserts. The GTN2s or 3 will not fit the ISCAR holder.

There are various qualities and grades of GTN2s and 3s available. Even though ARC sells Chinese origin, we are particular about our sourcing for inserts, and we pay a lot more for them, than 60p each. If the user is happy with the 60p investment, and it works for him/her, that is well and good, too.

Ketan at ARC.

Edited By Ketan Swali on 24/07/2019 06:46:48

Just spoke with Steven at AUSEE. His parting off blades and inserts come from the same place as ours.

Just like inserts, there are several grades of holders. ARC has tested holders from various sources from Japan, India and China, and settled on one specific maker from China.

Generally, there are good and bad makers of the 'black finish' ones. The black finish ones are usually more brittle (That in itself does not mean it is bad).These usually snap when there is failure. The 'bad' factory imitations are of seriously poor quality.

The Sumitomo ones are black finish, made from a form of spring steel. It allows for some give, but has proprietary inserts in the same way as ISCAR. So, the GTNs don't fit it. Price of Sumitomo holders are high, and more suitable for high production environment. I am guessing that the ISCAR one is in similar range.

So, as a result, ARC settled on the factory we use. The brown finish holders which ARC and AUSEE sell are made from (Chinese spec.) GB 60SI2MN Steel - a high quality alloy spring steel. It costs more than the general 'black finish' stuff. It does not mean that it is better or worse than the black holder. it just has 'more give' before bending or snapping, falling more in line with the Sumitomo idea, without the big cost.

Just like the black holders, there are very cheap brown finish holders, which are poor imitations, not made from the grade of steel specified above. But if they suit the users purpose in the hobby environment, and it works, the user is non the wiser. Some sellers using the auction platform state that their holder is made from a specific grade of steel. But how is the user going to check?, and does he really know, understand or care if it works for him/her?. There is nothing wrong with that, but 'with respect' when they talk about it in YouTube videos or on forums, how much do they really know about it? How much is true, false, money laundering?

Ketan at ARC.

.Ok thanks Ketan!

I will give them a go .

I have avoided buying thee from that auction site for the exact reason you stated and i have seen a few reviews of blades from another well know seller that seems to be giving products out for review on youtube and the reviews were not good to say the least! .

I have purchased a bit from Ausee and have been very happy with the quality and price .

For what it*s worth [not much, I suppose ] I bought one of those holders and tips from China and found them to be OK. I have a Craftsman lathe, 6" centre height and found that it had no problem handling 2 or 3 mm tips for parting off but 4mm tips were another matter. OK for grooving but not for parting, the machine just did not like them.

The holders are quite cheap ,about 14 Dollars, less in Euro,s and the tips are for buttons.

I found that they work better under power feed, something I would seldom try with HSS blades.

I always use a rear tool post for parting, since I found it more rigid.

Just my experience

PS No big problem if you break the tips ,they are cheap enough !

Many thanks Ketan, guess it just levers the tool seat open to release the insert.

Emgee

No they push against the rear of the insert and the "Flat" between the two circular stress relief holes.so it slides out. See ARC holder

You can get another type with a pivot pin that goes in the hole at the bottom of the blade and has a second flat pin that levers against the insert

Some blades do have a longer slot and the key does open up the slot in that case, such as the one Greenwood do

Edited By JasonB on 24/07/2019 13:14:56

Jason, thanks for the additional info.

Emgee

I dont have any insert type parting tools, all my parting is done with HSS.

I went to a rear tool holder on the mini lathe and using a 3/32 HSS blade it transformed parting off, the 918 I have just got also has a rear post. Using the front tool post I dont go any bigger than 1.5mm but again HSS.

I think Neil hit the nail on the head when he said its all about "confidence" I think that is so true, you just have to be brave and go for it, no hesitating just keep feeding it makes a world of difference.

Is it generally the case that the insert tools are superior to HSS for parting, I have thought about getting some but to date I have not.

Ron, I seem to remember Sparey making that very point when talking about parting off..

As far as I recall, he said "Keep the tool working with a steady feed ".

That does seem to be the way to go, but it can be SCARY !! at times.

Regarding removing the tips, I just prise them out with a small screwdriver, never knew there was a tool for the job !

Dear God, I have SO MUCH to learn !!

Thanks for your input Ketan, much appreciated.

Emgee,

This is what the Sumitomo insert removal tool looks like:

Ketan, just checked the make of my parting blade and it's 19mm made by Glanze, there are no holes and the Sumitomo tool looks like a good choice to remove the inserts.

Emgee

Twist of a small screwdriver works OK on my Glanze one.

The ARC Blade type is the best parting-off tool I've used. I'll risk ruffling a few feathers by saying that carbide inserts are almost always superior to HSS for anything! Reason being they are harder with much better heat performance.

BUT, you have to push them. They aren't at their best on slow, wobbly machines with weak motors. Nor are they a good idea on delicate parts! I use HSS about 10-20% of the time, mostly when a sharp tool is needed for fine work or I'm having trouble getting a good finish from carbide. For parting small diameter bendy objects I find it's safer to use sharp HSS, but carbide very obviously outperforms HSS on anything grown-up enough to take it.

Dave

Unless I missed it somewhere, I'd add a point I learnt only recently, on HSS parting-tools. The cutting edge needs to be square with the tool flank, and that of course at 90º to the lathe axis.

Reason for the square-ness is so the swarf is no wider than the cut, as it would be if the tool is angled.

I must admit I was surprised I'd not known this ages ago after struggling to part off with the tool ground at a small angle as I'd long supposed, to minimise the burr or pip!

Insert-tool holders are precision-made, and I find it far easier and more certain to square the tool to the lathe by very gently pushing the holder's flank against the chuck face. Certainly easier when setting-up for threading, than trying to manipulate a V-notch gauge between a small insert and a small-diameter work-piece on a fairly compact lathe!

My drawer of insert tooling including a cetarizit part off tool and Dormer grooving tools.

Despite my concerns about the additional overhang when used with my son's size 100 tool post, I ordered a GTN2 parting blade and block from Arc yesterday and was surprised when it arrived this morning. The lathe isn't very powerful for its size (1hp and no backgear), so parting off at 3 times the speed that I used with HSS has made things much easier. I had a lot of vibration at first, but this went away once I increased the feed rate.

I'm suitably impressed but probably getting over-confident now, as I plucked up the courage to let it keep feeding under power whilst taking a photo (16mm scale wheels from 1 1/4" bar).

Brian