Hi all,

I'm new here, all the google searches led me to this website, so i thought of joining and asking for a little help...

I'm not a model engineer, but looks like you guys use lathes a lot, so are probably the best people to seek advice.

I recently bought a Myford ML7 to help on some work I'm doing on a 1976 and 1979 Harley...

Its my first lathe and completly new to this type of engineering, have read a lot and watched a lot of youtube videos.... but there's stuff that you can only resolve if you have someone to ask..

So, I can do the turning and facing pretty good now..but parting is nowhere to be seen...
I just can't do it at all.

I've tried at high speed, low speed, centre height, just a litte below....and nothing, just get chatter.
I did manage to get a few nicely formed cuts coming off today, but promplty followed by a lot of chatter...tried easy on the feed, hard on the feed....

Basically I've tried everything and I dont know what else to do.

I'm trying to cut a spacer out of a 24mm bright steel rod, which already has a 13mm hole through it.
I have a quick change tool post, that I've lined the centre height with a dead live centre on the tailstock...

I have 10mm shank tools as that's what my tool post can take.
One is carbide, the other is a thin HSS blade, not very wide... chatters with both.

Both tools were completly flat on the top and after seeing some videos on youtube where the top had also been ground for clearence, i did that on the carbide and that's how i managed to get the few nice chips coming off...

Another question,
I read on the Myford manual about the speeds (ungeared and backgeared) when I engage the lever, closer to the chuck, to the top position - so its geared as the manual suggests - nothing turns, am i missing something?

Sorry for the long post, just wanted to give as much info as possible...

thanks in advance for the help.
Btw, I did get my Myford for a model engineer from Wales who had it for over 20 years!

JP

Hi - Try this link -Beginners questions -

Sorry seems I got the wrong link - try this Here we go - parting off

Parting off is the most difficult thing to achieve on a hobby lathe

All part of the learning experience

If everything isn't just right, and I mean everything, it won't work

I can only do it with the backgear engaged and an upside down tool on the back

Use the backgear and plenty of cutting fluid.

All that has happened by you moving the backgear lever alone is the backgear is engaged but cannot turn as it is also engaged with the spindle.

To engage the backgear on an ML7 raise the lever closest the chuck and also loosen the allen screw and locking dog away from the spindle (this screw can also have a bolt head) lift the belt cover and you should see it on the face of the big gear you may have to cut an allen key down to suit the available gap.

Lubrication some have an allen screw and some an oil nipple which must be lubricated to allow free running of the backgear against the spindle shaft.

If it still wont turn the backgear could have gummed onto the spindle, check for missing/broken teeth also.

Regards

Paul

JP,

Assuming your ML7 is not completely clapped-out, you should have no difficulty parting off if you follow these simple steps:

(1) Buy one of these: **LINK** This is by a large margin the best parting tool I have found at this size, and I tried quite a lot before I found it. The shape of the tip is the vital thing, it curls the chip so it is narrower than the gap, which totally avoids it jamming in the gap (the cause of many of the problems, especially with steel).

(2) Set the tool up in whatever you use as a toolpost - it ought to be as rigid as possible. And - this is most important - make sure the tool is exactly square on to the lathe axis.

(3) Locate the tool where you want the cut to be.

(4) Lock all the slides you can, other than the cross slide.

(5) Select a fairly low speed. In the bad old days, using old-style tools, I used backgear, now I just use a low direct drive speed.

(6) Switch on and advance the tool into the work. Don't hesitate, feed slowly but firmly (having the tool rub does nothing any good - and for work-hardening materials like stainless steel or titanium it is disastrous). For mild steel, drip feed neat cutting oil on to the work - every few mm of cut should be enough. For other materials, use oil or not as suits the material (dry for cast iron or brass, paraffin for aluminum, neat cutting oil for most others).

If this does not work well, your lathe may need a check-up.

I have a rear toolpost, but with this set-up I have never found it necassary, and it is a PITA to have to use it so best avoided. Incidentally I use a (genuine) Dickson QC toolpost, and although some people worry about the rigidity of these for parting off, I find it works fine. I don't have power cross-feed on my Myford, but I do on my Harrison - and with a larger version of the above set-up I regularly use PXF for parting off; works like a charm.

David

Edited By David Littlewood on 21/01/2013 12:56:18

Hi all,

thanks for the replies!

I'm suffering quite bad from flu at the moment, but I'll be trying all that once Im in a better shape to spend the day in the garage..

@David Littlewood - does that tool fit a 10mm shank? I think i've seen a parting tool similar, think the brand was Glaze?or Glanze?

@Paul - I'll try that, all i did was move the gear lever up, dont think the manual is very explicit, i did notice the little screw there, but really dont know what im doing...hahaha

In terms of oils, I asked the previous owner what he used (as he had it for over 20 years) he said he used non multigrade engine oil SAE30 and moly disuphide grease on where the nipples are.
Does this sound right? I have some SAE30 oil I use on my air compressor, so i guess that's good to go in the oil drips?
Not sure about the grease though, as ive read somewhere not to use grease where nipples are, as it might seize things up?? should only be oil?

JP

JP. I assume that you live in the UK since you bought your lathe in Wales? If so I am sure that a plea for help which gave an indication of where you live would bring a few offers of help and advice. I live in Millport on the Isle of Cumbrae which is a wee bit remote but if you are anywhere near me then just ask.

Ho yes!I forgot to add that little bit of info.... yes altough my name is Santos, I live in UK.

Im from Portugal originaly, but been living over here for 9 years now, I live in Newbury, Berkshire

Having someone to show me, or even someone with an ML7 that I could drive to to show me basic stuff that would be a godsend

Hi JP,

We have a saying in the UK - "Parting is such sweet sorrow".

One problem many people have is being too cautious. If everything else is apparently right, it may be that your early problems have made you over cautious. One thing though, as TerryD has pointed out elsewhere, as long as you have enough power available the SMALLER the diameter, the trickier it gets.

Neil

P.S. it seems Portugal is the most British part of mainland Europe

Edited By Stub Mandrel on 21/01/2013 20:29:35

Hahaha, yes indeed, there's a big Brit community over there, I guess sunny weather, good beer and golf courses is very attractive...

I've also been past the too cautious, as in one of the youtuve videos I watched, the guy said he found it easier if he was less delicate on it..
I tried it... didnt work!

But, i'm keen now to experiment with the backgear and take on some of the tips from this thread and the other linked here...

Hopefully this flu will be gone by the weekend and I'll be able to hide in the garage again

My ML7 jumps about like a mad frog when parting, I find the best way to deal with it is to go steaming in (so to say).

I could never part off with any success with a highly modded ML7, there was way too much flex. The only relative success was with cobalt tool steel ground up 1/16" wide, but could only go so deep, not the 5.5mm required here without probs.

The only tips ever broke are when using too slow ie less than 500 rpm, couldnt catch in time.

Just gave away one of those Sandvik part off tools, had it 20 odd years even in the ML7 days. Current machine at best because couldnt generate high enough speeds so kept binding up. Swarf down the sides etc jamming. Plus it always left a right burr on the part wanted so had to centre up and bore at an angle knocking burr off. Glad to see back of it.

Just accumulated 10 Iscar and Arno cutters of various designs and types of tips, like chalk and cheese compared with above Sandvik. These are meant to run like all others in excess of 2000rpm with coolant.

Ever wondered why you can start to part off, go in a certain distance then plays up, its the heat.

HI
Try steading the workpeice with a centre in the 13 mm hole in the tailstock.\

Or part off from the back .
Nobby

Edited By Nobby on 21/01/2013 22:38:26

JP,

The Q-Cut has a 12 mm shank, but it is quite easy to get the right height in my S00 (Myford size) Dickson setup.

I have a number of Glanze tools, including a slightly larger version of the Q-Cut, on my M300. They are OK, but don't have quite the same quality. The toolholders are not bad, but the normal turning tips seem to break more easily. Having said that, my Glanze parting tool parts off fine under power XF on the M300, which is of course a much bigger and more rigid machine.

Any parting tool will leave a pip somewhere. With HSS tools, you can make it be on the stock side by grinding the front of the tool at a slight angle - but then you will have far more problems as the tool will be pushed sideways on its way in.

Parting off with a tailstock support is not recomended; you can use one part way into the cut, but don't forget to remove it for the last bit.

David

Edited By David Littlewood on 21/01/2013 23:05:17

Parting off from the back is a lot easier on an ML7 if using a rear toolpost and can be carried out using cheap HSS tooling, some years ago I bought a HSS rear parting toolpost (from RDG I think) it was such a great success I fitted it with an adaptor plate and use it on my Boxford lathe too, it is in very regular use and only requires a lick on the grinder every now and again to put the edge back.

The Boxford will depending on material part stock using the power cross feed using the same rear toolpost.

As Nobby says why not use a centre in the tailstock to support the work as long as you dont cut all the way through thats fine, finish the last bit with a hacksaw and face off if you need to.

Plenty of cutting oil always helps unless it's CI of course.

Paul

Using a tailstock centre is pretty much an essential part of learning about hobby lathes

They greatly increase the stiffness of a workpiece for any job at all

Ady,

When parting off an unsupported piece, the piece being removed falls away cleanly causing no damage. If you complete the parting with a tailstock centre in place, the piece being removed cannot do this, and will fall sideways trapping the tool, causing damage to the work and possibly breaking the tool. Still, if that's the way you wish to do it, it's your choice.

David

So cut it down to a pip, then remove the tailstock support

As me old boss used to say

Don't bring me problems, bring me solutions

Edited By Ady1 on 22/01/2013 21:37:38

Ady,

I thought I did. I haven't had any problem parting off since I started doing it the way I set out above.

David