Duncan and Neil's suggestion (also recommended by Martin Cleave) of half the infeed on the 90 degree set topslide (arc tan 0.5 = 26.6 degrees) also results in the reduced cutting forces and a cut on the RHS of the tool for 55 & 60 degree threads as well as giving direct depth reading. I'm not sure my poor old ML7 would cope with a directly cut thread at 8TPI or 3.5mm pitch!

The method also has the big advantage IMHO that broadening the cut while at full depth is a cinch on either side of the thread crest just by adjusting the topslide.

HTH

Jon

Just a thought, but are the jaws inserted in the right order?

It might be that the previous owner did their best to correct for the asymmetry that would create?

Jon

I can't say that I'd noticed much difference in finish between the two sides of a thread. After all I thought the idea was that the intent to use a lower angle than 30/27.5 was to ensure that the right hand flank was "cut" on every pass too? It might be my inexperience though.

Martin Cleave (Screwcutting in the lathe - WPS No 3) addresses the topic on page 157 (poor finish) and says that it may be due to "too pedantic following of top slide advancements" or the tool not set to cut on the trailing edge.

Jon

Thanks Russell - it's a fun build and hopefully I'll end up with a useful set-up. I'm planning to make the full set of accessories and particularly the end-mill sharpening fixture.

Did a bit more to my HH advanced rest last night. Finished the two rotating dovetail slides on the RHS of the second photo. Still a fair bit to do but getting there.

Also changed over to imgur to see if it solves the 3rd party hosting picture problem of Photobucket...

Jon

Hi Nige,

The ML7 handbook in pdf can be downloaded from here **LINK**

Pages 25, 26 and 27 show the same nomenclature to help with your setups.

HTH

Jon

Hi Nige,

This ebay seller lists them... **LINK**

Never tried them but HTH

Jon

It could be that the stock is bending away from the tool but if the cuts are light and the tool sharp enough then it could be fixed by at least one of a couple of things.

1) The headstock needs to be turned clockwise in relation to the bed - the mandrel end needs to come forwards, or

2) The bed is twisted and the front tailstock end needs to be lifted upwards to bring on the cut more towards the tailstock end.

HTH

Jon

Nige,

I've used the Arc product and Dormer Supercut (**LINK**) but got fed up with the high price and bought some of this oil off ebay **LINK**.

Twice the price for 5 times the quantity and seems to do the job for me.

HTH

Jon

Whitworth's self-acting drilling machine and self-acting radial drilling machine were displayed at the 1851 Exhibition and would have been more than capable of boring plate I'd have thought...

**LINK**

See figures 7 & 8.

Jon

Sorry for being skeptical but doesn't this risk drawing moisture laden air from the house (cooking steam etc) onto the cold surfaces of the cellar potentially making the damp issue worse there?

I'd be inclined to try to get air movement and a through-draught in the cellar so that the moisture you breathe out can be got rid of ASAP.

Good luck and HTH

Jon

I bought some Birchwood Casey Super Blue and it's very easy and quick on mild steel.

Can't say I "like toxic chemicals" as per Ian's comments above but sometimes they make sense.

HTH

Jon

They are still available from Myford and can be found here...

**LINK**

£264 inc VAT. Quite eye-watering to be honest

Jon

Edited By Jon Gibbs on 27/07/2017 11:34:47

Hi Alfie,

What speed were you running the carbide end-mill compared to the HSS?

Carbide should be run faster (~3x) and worked harder than HSS.

HTH

Jon

Not real world evidence but both petrol and diesel have roughly the same energy in 1 litre as 10 kWhr. So your approximation of 1 unit per mile isn't far off assuming similar efficiencies between power sources.

We need some leadership from the government to give a boost to R&D IMHO and this is as good as anything they've come up with so far.

We might have left Europe by 2040. We'll be eating goodness knows what (GM fruit and veg, hormone and chlorinated meat etc), with sea levels lapping at our ankles (from Greenland - I'm glad I don't live on Portsea Island anymore) but at least air pollution levels may be set to improve .

Jon

Another thought would be freezer spray on the seat post while gently warming the seat tube.

**LINK**

I don't think the freezer spray will damage the paintwork, especially if sprayed on the inside and may be enough to break the seizure.

I use the 2-stroke Aspen in my chainsaw, strimmer and leaf blower. The big advantage for me is that the fuel can stay in there with no chance of it going off and they'll start first time no matter how long between uses. So, admittedly it's expensive but there's no waste and far less hassle.

Jon

+1 Very nice restoration.

...and nice looking dials too - I was tempted to upgrade mine but at £41 each I'll be sticking with the zamak dials for a while yet.

The thread probably belongs in the tearoom but it seemed a pretty civilized exchange of opposing views to me.