Myford or any other adjustable rear parting tool

[SteviegtrParticipant @steviegtr]

I always sort of had problems parting off with the myford lathe. It is not uncommon. I eventually made a rear mounted version of my own design. For some it will be a too long a series to watch. But for others it may give a little insight of how i went about it. Beware it's 3 video's long , but works just as intended now. I show at the end parting some mild steel bar. Since then i got more ambitious & tried a larger 25mm piece of stainless. Also using more steady force.

It works perfectly. The cost was very little A bought blade & some inserts + a piece of mild steel bar EN1A i believe. For anyone wanting to have a peek, it's here.

Steve.

Edited By Steviegtr on 13/09/2022 22:48:57

[SteviegtrParticipant @steviegtr]

Making a alternative type parting tool

[Chris CrewParticipant @chriscrew66644]

I had second thoughts about the comment I made, so deleted it.

Edited By Chris Crew on 14/09/2022 08:38:44

[SteviegtrParticipant @steviegtr]

Posted by Chris Crew on 14/09/2022 08:34:48:

I had second thoughts about the comment I made, so deleted it.

Edited By Chris Crew on 14/09/2022 08:38:44

Thanks Chris. Back to the Zoo now. HaHa. Take care.

Steve.

[Harry WilkesParticipant @harrywilkes58467]

Watched the vids well done, like many I had trouble parting so I looked in the box's of bit's that came with my lathe found a Myford rear parting off tool post problem gone !

H

[Howard LewisParticipant @howardlewis46836]

Made a rear toolpost for my ML7, and had no more parting problems.

(Ruined an inserted carbide parting tool in the front post! )

Having upgraded to something larger, one of the first jobs was to make a four way indexing rear toolpost, to take the OLD HSS parting blade (With Zero top rake )

So good that I now use power feed tom part off!

If you can, fit and use a rear toolpost

Howard

[SteviegtrParticipant @steviegtr]

Posted by Howard Lewis on 16/09/2022 15:01:41:

Made a rear toolpost for my ML7, and had no more parting problems.

(Ruined an inserted carbide parting tool in the front post! )

Having upgraded to something larger, one of the first jobs was to make a four way indexing rear toolpost, to take the OLD HSS parting blade (With Zero top rake )

So good that I now use power feed tom part off!

If you can, fit and use a rear toolpost

Howard

I'm glad you posted this as I wondered if using the power feed was plausible.

Steve.

[Howard LewisParticipant @howardlewis46836]

The good thing about using power feed is that the feed is constant and consistent, so ,there should ,be no fear of letting the tool rub, or of over feeding and having a dig in.

If no power feed is available, the skill to feed steadily, and not too fast, needs to be acquired. (One of the first things that I was taught in the Training School )

One advantage of the rear toolpost is that with the tool, being inverted, the swarf falls out, with less fear of clogging the cut.

Howard

Edited By Howard Lewis on 16/09/2022 15:14:52

[SteviegtrParticipant @steviegtr]

Thanks for that Howard

Steve

[David George 1Participant @davidgeorge1]

I have made a rear toolpost from a casting base and mild steel top clamps for a blade and tip. Never been a problem since I made it and I can slide it in and out to suit diamiter of job.

David

[not done it yetParticipant @notdoneityet]

Posted by Steviegtr on 16/09/2022 15:05:23:

I'm glad you posted this as I wondered if using the power feed was plausible.

Steve.

Just make sure that when the cutter reaches the centre, if cutting a solid bar, that the cross slide still has some travel.

If not, you will likely break something – cross slide power feed drive, feed nut threads or something else.

[SteviegtrParticipant @steviegtr]

That was my thinking. Maybe for now I will do it manually. I already sprained the leadscrew with the front parting tool fiasco. It's getting eased now but was stiff for a while.

Steve.

[SteviegtrParticipant @steviegtr]

Posted by David George 1 on 16/09/2022 21:45:12:

I have made a rear toolpost from a casting base and mild steel top clamps for a blade and tip. Never been a problem since I made it and I can slide it in and out to suit diamiter of job.

David

Looks good David.

Steve.

Edited By Steviegtr on 17/09/2022 00:18:15

[John RutzenParticipant @johnrutzen76569]

I have a rear parting toolpost I made for my Harrison M250 but I find that it isn't dig-ins that are the problem. What happens is that a bit of swarf welds itself in the cut , jamming everything up. So I am very cautious about parting off, I keep my hand on the clutch lever all the time so I can stop it quickly if it goes wrong.

[Alan JacksonParticipant @alanjackson47790]

How about doing this, it can be mounted on the front side if the chuck is screwed on or the rear side if the chuck has a bolted or camlock mounting.

Alan

[Tony Pratt 1Participant @tonypratt1]

Posted by John Rutzen on 17/09/2022 09:20:11:

I have a rear parting toolpost I made for my Harrison M250 but I find that it isn't dig-ins that are the problem. What happens is that a bit of swarf welds itself in the cut , jamming everything up. So I am very cautious about parting off, I keep my hand on the clutch lever all the time so I can stop it quickly if it goes wrong.

What cutting oil or coolant do you use?

Tony

[Chris CrewParticipant @chriscrew66644]

"So I am very cautious about parting off, I keep my hand on the clutch lever all the time so I can stop it quickly if it goes wrong".

May I suggest that may well be your problem. You have to be a little fearless when parting-off, once the tool starts cutting you have to keep it cutting, use plenty of coolant/lubricant and if you are parting-off a larger diameter don't be afraid to retract the tool and increase the speed as the diameter decreases. Plunge the tool in to start cutting again. You really should be laughing at parting off on a lathe like the Harrison 250.

[Howard LewisParticipant @howardlewis46836]

Agreed! I always lubricate by some means (A steady drip, of soluble oil syphon fed from an overhead bottle, or ordinary lub oil applied frequently with a brush.

And NEVER let the tool rub, keep it cutting. My parting tool has Zero Top Rake.

My sliding power feed is 0.0022"/rev so the cross feed is probably 0.0045" or 0.0011" per rev (Not sure which ) but it works for me.

Howard

Edited By Howard Lewis on 17/09/2022 17:21:57

[John RutzenParticipant @johnrutzen76569]

Yes, maybe I need to arrange a constant coolant drip, I just apply water soluble stuff with a syringe. Its difficult to keep it in the cut because it gets flung out. I think I don't use it much because it's a faddle to clean the machine tray and I don't like it being oily. I've never dared to part off under power feed!

Edited By John Rutzen on 17/09/2022 17:34:55

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