Best value parting tool for mild steel?

Hi

I have a bunch of cheap lathe tools I got when I started and after buying a single, nice carbide turning tool, I realise how many of my problems were coming from the low quality cheap set of tools I had bought.

I am at the point of needing to do some parting and decided I would buy myself a nice new parting tool. Have you guys got recommendations on what to go for, especially users of the Warco WM250? Will be mostly mild steel I am cutting. As I am rather taken with my new carbide tipped turning tool I am leaning towards that for a parting tool too.

New or used is good, though if the latter any good suggestions on where to look for second hand gear? Best to get one with a holder or not? RDG have some holder type ones for about 45 quid, carbide / index.

Cheers!

Edited By Ross Lloyd 1 on 08/01/2019 17:09:23

Well, I use RDG's cheap holder with a 5/16 x 1/16" blade over a 1/8" packing insert in my WM250V. Works for me. I break the blade occasionally if I'm careless, so I keep a spare.

Edited By Mick B1 on 08/01/2019 17:30:19

When i bought an at least second hand Myford ML7 back in the early 80s, I was given a 3/32" wide HSS parting tool in its holder. I am still using it, in a rear toolpost, on my bigger lathe;

On this basis, it probably has another 8 - 10 years life left in it ;and it is by no means near being worn out!.

I usually dribble soluble oil on to it whilst in use, and have become brave enough to use it with a 0.00225"/rev power feed.

I have tried a replaceable 2mm Carbide tip parting tool in the front toolpost, and have given up using it because of the dig ins and the cost of replacing broken tips.

Possibly I have been both careless and unlucky, but the HSS tool has been less trouble and less costly.

Howard

Ross, I have a DB10 lathe which is essentially the same machine as yours. After experimenting with a few parting tools I find this one performs well on steel :-

The blades are easy to sharpen and once you have the holder replacement blades are cheap anyway.

**LINK**

Try swapping the tipped tool to your rear toolpsst position Howard. I've found the tipped tool blades far superior to HSS blades. Tipped ones tend to stay on course and less prone to jam ups, at least for me.

I now only use HSS with cobalt blades.......not had time to try the rear mounted tool holder on my Myford S7 yet........

BUT I do grind a small groove on the top edge of the blade with a Dremel and use a contsant heavy flow of cutting fluid...

had loads'a problems with Carbide, not the tips but the holders, lower support cracking......always used at the next higher chuck speed when parting off......

not brave enought to use a power feed.......

on the big diameters always use the bandsaw to cut the part from the stock and then face off.......saves my nerves.......

I use the standard Eclipse HSS parting tool on both a Myford 7 and an Emco Super 11, no real tool post and no problems. However I have tried the carbide blade and holder style but did not like them due to the additional overhang, I also tried one of this style **LINK** not from Arc but it works very well, however I still use the HSS tool for almost all of my work.

John

Rear mounted 2mm tipped tool for me from ARC. Tips last months if well lubricated in use and all materials are usually OK. Some of the tougher EN16/EN19T need a bit of care. You need to reprograme your mind and up the spindle speed for best performance. 800 to 1000 revs with 0.05mm (two thou) per rev feed on 1 1/2" EN1A is doable.

I use one similar to this in most of my parting off; I also use a 10mm HSS for smaller jobs Both have proved to be very hardy in the parting off they've done. Usual disclaimer applies.

**LINK**

George.

What size tool can you fit in your tool post Ross?

If you are using a QCTP I strongly suggest a parting blade holder made to fit the tool post. You want to keep the centerline of the parting tool as close to the centerline of the cross slide as possible. The object of this is to minimize sideways deflection of the tool. Such deflection causes the parting blade to bind in the cut jamming the tool and likely breaking it.

I use the Glanze clamp type mostly. Parts like butter on my chipmaster, with a mirror finish.
Only managed to damage one insert when doing something silly.
**LINK**

I too have one from Chronos the same as Stuart's link, not is a direct fitting tool holder, just in a standard one.

Finish on 40mm steel

1.6mm slice off 65mm dia CI

Only got a video of part cut in 38mm 6082

Depends on the material and its size in my view Ross.

For larger mild steel - I use this rear mounted insert tool (photo below) on my S7 and it will part through 2"+ steel no problem - but the tip is 3mm wide. The only inserts I've broken have been under interrupted cuts - so I revert to HSS for those and move slightly side to side as I go in to ensure clearance. I still use HSS on smaller diameter steel (I have another rear tool post for that) but have purchased a smaller insert tool that I need to make a holder for (another TUIT)

For brass (which is mostly <1" dia) I use HSS (front mounted) tools and they work just fine and are simple to keep sharp. Small diameter work really only needs a thin/short cutting blade which saves on material.

So as usual - the answer depends what you are trying to part - I don't think there is a single 'best' solution (not for my work at least)

IanT

Answer depends on so many things:

• How well set up your lathe is.
• How rigid it is.
• What diameters you want to cut.
• How confident you are with parting and your personal technique (are you a timorous prodder or a gung-ho wincher?)
• If you have power feed.

The WM250 should be happy with carbide inserts on the front with a good positive feed, but if you are cautious a rear toolpost and/or a sharp HSS tool might suit you better.

Neil

On my WM250 I use the RDG indexable parting tool 3mm x 19mm with 12mm shank. I find it works very well but you do need to ensure that the blade is absolutely square to the axis. Just make sure you lock the carriage and top slide, plenty of revs and then wind the tool in with gusto! Feeding slowly with carbide inserts is just asking for trouble. Also,as far as possible I always part-off as close to the chuck as possible.

Thanks for all the replies, in the end I went with the RDG holder with 3mm insert. Am already seeing some of the things you guys mentioned, I was running it through aluminium, 500mm diameter. After the second parting operation the tool was blunt and had lost its edge, not sure if I was running too slow for ally / carbide. I started at 300 rpm and gave it a bit more juice to around 700, I didn't want to go too high though as it was quite a long piece of stock being held in a steady (basically cutting it off due to my vice being broken and couldnt hand saw it).

I understand ally is more of a pain to deal with anyway. Should I have been running 1200 rpm or something? Before it blunted though, as long as I gave it a good push to avoid rubbing, and used plenty of oil, it cut really nicely.

500mm???? How big is your lathe. I assume you mean 50mm? There are cutting speed tables online that are worth referring to.

Oops yes brain fart, 50mm. I have a copy of machinerys handbook, for ally it said 680 opt, 2080 avg for the cutting speed. As the speed / dia charts dont go up that high I just interpolated for the rpms. That said I now wonder if I made the same cock up with the diameter. I will go and check!

Thanks for replying

EDIT: Actually tell a lie, I was thinking about the turning I did after. I just went with 350 rpm to start and increased to 700. Perhaps I have missed it but I have not seen a specific section in machinery's on parting, and generally halve the turning speed on advice from Toms Techniques (youtuber)

Edited By Ross Lloyd 1 on 17/01/2019 10:20:43