New Toy Day

This topic has 14 replies, 10 voices, and was last updated 21 June 2026 at 15:10 by old mart.

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20 June 2026 at 20:13 #852782
Julie Ann
Participant
@julieann
Finally got around to buying a rear/auxillary toolpost for my Harrison M300:

Bought on Ebay and arrived today. I’ve cleaned it up, done some fettling and replaced a couple of screws that were supposed to be M6 but definitely were not!

Despite the parting off tool shown I am not sure what I will use the toolpost for; I find parting off is fine from the front. But you can never have too many tools, and if you haven’t got it you cannot plan a job that would make use of it.

Julie
Advert

20 June 2026 at 20:15 #852787
renardiere7
Participant
@renardiere7
It’s the only place to mount a parting tool. Total game changer!
20 June 2026 at 20:50 #852795
JasonB
Moderator
@jasonb
If you did not have the Ainjest I would have said it would be useful for threading away from a shoulder. The nut on the top rules out standing your tea mug on it.

Suppose it may be easier for small batches when you don’t want to set up the Britain.
20 June 2026 at 21:17 #852804
Diogenes
Participant
@diogenes
Looks a bit more versatile than the average RTP and one of those things that sooner or later will make you glad you bought it.
20 June 2026 at 21:39 #852807
Julie Ann
Participant
@julieann
On 20 June 2026 at 20:15 renardiere7 Said:

Total game changer!

Why is that?

Julie
20 June 2026 at 21:44 #852809
Julie Ann
Participant
@julieann
On 20 June 2026 at 20:50 JasonB Said:

Suppose it may be easier for small batches when you don’t want to set up the Britain.

Could well be, for items too big for the Britan. Although not visible there is a hole in the headstock end of the base and a tapped hole (visible bottom left) at right angles for a locking screw. I suspect it is intended for a stop bar.

I will need to get the workshop crane sorted though, as the capstan unit I have for the lathe is now too heavy for me to lift.

Julie
20 June 2026 at 22:54 #852819
howardb
Participant
@howardb
I keep a 45 deg chamfering tool bit in the rear toolpost of my S7, always there when you need it, aligned and set on centre height.

What is it with parting off that spooks ME members?
21 June 2026 at 04:00 #852825
not done it yet
Participant
@notdoneityet
On 20 June 2026 at 22:54 howardb Said:

….

What is it with parting off that spooks ME members?

Rigidity?
21 June 2026 at 06:54 #852827
martin haysom
Participant
@martinhaysom48469
On 21 June 2026 at 04:00 not done it yet Said:

On 20 June 2026 at 22:54 howardb Said:

….

What is it with parting off that spooks ME members?

Rigidity?

yes
21 June 2026 at 07:12 #852829
JasonB
Moderator
@jasonb
…………Or the lack of it in their lathe that required a rear tool post, like Julie I part from the front and get on OK.

“Keeping” the RTP (rear tool post) in place may be an issue, it does not look like you have that much room between the front and rear ones and things may get in the way of your larger jobs. Not such an issue for those with extended top slides but not all have those. I tend to run my topslide in about 40% of the cross slides length so keeping a RTP in place would be a problem for me so easier to just use the front QCTP when I want to part or chamfer
21 June 2026 at 10:28 #852855
renardiere7
Participant
@renardiere7
To answer the question. The rear tool post was a game changer for me because I now have reliable stable parting continuously set up. I can part most materials under power even stainless steel with no issues.

On the QCTP I was managing parting ok previously but there were occasional issues. I find now for batch working it speeds things up no end.
21 June 2026 at 10:56 #852858
alecs
Participant
@alecs
On my Myford ML7 aka “FlexiFlyer” the rear toolpost is definitely better for parting off. Thats my lived experience. The debate on whether that is due to geometry and vectors or just the chips falling out of the groove and not jamming has raged since at least 50 years before the internet amplified it even more. So let’s no go down that rabid hole.

But on the larger, more rigid lathes I used at work, EG Dean Smith and Grace 16″ swing or Monarch 10EE etc, 1/8″ wide parting tool in the normal front toolpost could be driven in with aplomb under power feed, with a flooding of suds. I imagine the Harrison would be much the same?
21 June 2026 at 12:03 #852866
Howard Lewis
Participant
@howardlewis46836
For less rigid hobby lathes, parting off using a rear toolpost, seems to improve rigidity (Forces on the dovetails?) AND the swarf falls away, rather than builing up and clogging the cut.

Bigger and more powerful machines, using wider blades may benefit from there being more room for the swarf to move out of the way, but using narrow parting blades does not give that, hence swarf falling away from an inverted, narrow tool makes life so much easier.

Additionally, even with a 3/32 blade, a gravity fed steady drip of soluble oil does make make life less stressful.

Howard
21 June 2026 at 13:25 #852874
alecs
Participant
@alecs
Yes on my Myford with inverted rear HSS 2mm parting blade, I drip feed oil from a handheld squirter bottle or oil can. I used to faff about mixing soluable oil but have found that hydraulic oil or motor oil squirted from the same oil can I use on the headstock bearings etc works just as well and does not rust the machine.

Running dry, I have snapped several HSS parting blades, so learned my lesson!
21 June 2026 at 15:10 #852897
old mart
Participant
@oldmart
I made one for the museum’s Smart & Brown model A which holds either 26 or 32mm blades inverted. The cross slide had to be removed for drilling and tapping as it is just flat topped. At the same time I added a rear carriage lock so that it can be better at resisting the lifting forces. It is only used for potentially difficult jobs, but not only stiffens up the parting,but swarf benefits from gravity.
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