Another Harrison M300 Rebuild

[scottmk1]

Mine is metric, 16mm diameter 2.5mm pitch. I will either make on or use some ready made screw & join it to the other half as suggested above.

 

[scottmk1]

@Shox Dr , when you stripped your lathe have it ground, how far did you go, or have to for them to be able to carry out the work?

 

[Shox Dr]

They need the head, just in case it needs scraping in and the tailstock for the same

And it needs striping, if only to make is lighter

 

[scottmk1]

Ok thanks. I have the bed stripped bare, saddle, cross slide, top slide & tail stock stripped. The head, screw cutting gearbox and apron are off but not stripped so should be pretty much ready.

The screw cutting gearbox was manky inside, with some rust in places. I'm sure it will be fine though.

 

[scottmk1]

Got the top slide in bits now. Unfortunately the gib strip has a kink in at the tool post end, so I think it will need a new one. Anyone know what sort of steel they are usually made from?

 

[Ian X]

Got the top slide in bits now. Unfortunately the gib strip has a kink in at the tool post end, so I think it will need a new one. Anyone know what sort of steel they are usually made from?

View attachment 74079

They are usually made of ductile CI, Meehanite if you can source some easily. Any old iron will do the job if you can find something close enough in size to cut up and have someone grind for you.

 

[Ian X]

You should inspect the gearbox teeth with a good glass and illumination. Dress off any burrs on the outsides of the teeth that come from exuberant gear changes.

 

[scottmk1]

Thanks Ian, I have sourced a good used gib along with a few other parts. The bulk of the machine is away to get re ground and I'm now in the process of gather the parts I require.

 

[Ian X]

Thanks Ian, I have sourced a good used gib along with a few other parts. The bulk of the machine is away to get re ground and I'm now in the process of gather the parts I require.

I guess that you will be a busy man with this job Scott. Images of what you have, what you have had worked on and what you have assembled are appreciated and valued by people owning machine tools of the vintage sort.
If you find time then please to post any images of work done. For people not fancying a contemporary Chinese product there is much value in the experience of others who put effort into the older and generally more solid metal.

 

[scottmk1]

Hi Ian. Thanks for the comments, I intend on posting more info & pics as work gets done, however since the last post not much has happened. The bulk of the machine is still away getting the ways ground and all I have done since then is clean a few parts. Next up will probably be stripping the apron so I will get some pics of that.

 

[mylesdw]

Keep up the posts, they are most interesting. I am keen to hear more about the whole regrinding process and how it works.

 

[Shox Dr]

Who's grinding it?

 

[scottmk1]

Hi, I will post more once I've got more done, at present it's all stripped & bits away for grinding. I have got hold of some spares that I needed & continue to hunt for more.

I need to paint it too, so what's the best machine paint that doesn't cost the earth?

@Shox Dr the grinding is being done by Brian at Slideway Services.

 

[Spark plug]

Cromadex is very good machenery paint don't know how mutch it is these days, or if you have a local supplier.

 

[scottmk1]

Cheers I will google it & see what I can find.

 

[Shox Dr]

Keep up the posts, they are most interesting. I am keen to hear more about the whole regrinding process and how it works.

...grinding is being done by Brian at Slideway Services.

He uses really really big grinders, topslide for a M300 been cut, to give you the scale, that picture was taken in his old shop down the road, from where he is now. One of his machines was from Bridgeport in Bridlington, one of only two in the world.

 

[scottmk1]

Yep I seen his machines when I was down there. Hopefully I will get another good look when I go back to collect the parts he is grinding.

 

[Maker]

He uses really really big grinders, topslide for a M300 been cut, to give you the scale, that picture was taken in his old shop down the road, from where he is now. One of his machines was from Bridgeport in Bridlington, one of only two in the world.

It's hard to tell on a phone, but is that mag base on a compound sine table? I'd love to look around his workshop.

 

[scottmk1]

Ok, getting on with this again after some other stuff needed doing.

I re measured my worn out cross feed screw, it's 5/8" 10tpi acme. It has the Gammet dual reading dials which have been well abused but that's another story.

I have acquired another cross feed screw, apparently from an M300, but it's different than the one that I removed. In the picture the top one is what came off, the bottom two piece is the newly acquired one. They are the same thread and the cross feed nuts are the same shape/size/design.

Anyone able to ID the two piece screw? It is in good condition so I'd like to use it, but if it means chopping up I may sell it to someone that needs it for their machine.

 

[scottmk1]

Spoke to the person I bought the feed screw from, looks like it is the one required to use a taper turning attachment on the M300.