My Harrison M400

[Munkul]

Rotagrip are excellent in this regard. if you can tell them the tooth pitch (they will explain how to measure them) and the slot dimensions.
I am confident they will be able to workout what number the chuck is.

I know what number the chuck is, it has the original Pratt number stamped in. Its a 250mm iron super precision 3jaw.

 

[Milkybars]

In that case if Thame workholding do soft jaws for it, this will provide accurate measurement of all dimensions

 

[Munkul]

I can't resist posting...

Pulled lathe out


Stripped lathe down. Leaving the saddle and cross-slide alone.



Pressure washed, dried, covered in WD40 and loaded on the trailer to take away.




I have LOTS of stuff to clean, now!



List of things I definitely need:
- new way wipers
- new drive belts
- new screwcutting feeds gearbox gasket
- replacement oils

The oil was clean enough, better than I expected TBH. I didn't expect the screwcutting oil to be as thick, though!
If BD don't need to touch the headstock end ways, it will drop straight back on, and I don't intend opening up the headstock or the feeds gearbox.
The Apron is fine too, but I need to sort the cross slide power feed lever detent (it won't hold in gear) and also the carriage handwheel engagement (should be easy to build back up).

Really quite happy up to this point. All the wear i suspected on the rack and pinion turned out to be mostly dirt and grime making it look bad. In reality, it's only moderately worn, and it'll do plenty work yet.

Ordered new drive belts. Is there somewhere I can order the gasket and felts from, or will I have to make my own?

 

[Shox Dr]

It will need all the bed grinding as everything either sit on it or hangs off it. The underneath of the saddle is built up with Turcite (sp) otherwise the lead screw won’t engag.

 

[Munkul]

It will need all the bed grinding as everything either sit on it or hangs off it. The underneath of the saddle is built up with Turcite (sp) otherwise the lead screw won’t engag.

It will get what the experts tell me it needs

 

[Munkul]

Got it back this week
We promptly started cleaning bits up and fitting them yesterday.
I'm waiting for some gasket material for the screw cutting box, that's why I haven't fitted it yet. Same with the apron - I pulled the front off last night to investigate the power feed mechanism since it wasn't holding the cross feed in on its own.

 

[Brad93]

Have they turcited the headstock and tailstock too?

 

[Munkul]

Has anyone had one of these power feed mechanisms apart? The torque limiting detent system is a bit strange... And this little lever looks like it should have a bush in it between the larger hole and the smaller pin.

 

[Brad93]

Have you got an exploded diagram?

 

[Munkul]

Have they turcited the headstock and tailstock too?

Not the headstock the drop in height there doesn't matter. They took off 18 thou so quite worn!
They turcited the tailstock and bedded it in properly. Ground the cross slide ways and turcited that too.
Everything is minted.
One could argue that the headstock should be scraped to the reground ways/vice versa... But... I can't see it making a shade of difference alignment wise, I'll have to level the machine, take some test cuts, see if I can take anything out with the levelling feet, and shim/scrape the headstock as a very last resort.

 

[Brad93]

But does that not mean that the feedshaft and screw cutting box are out of alignment? Also if they turcited the tailstock that will be higher than the headstock?

 

[Munkul]

Have you got an exploded diagram?

Yeah I have, it doesn't show anything. It's maybe meant to be like that, but I thought I'd ask anyway. I've found the adjustment to compensate for detent wear, and I've adjusted it a little, so when I put it back together I'll be able to see if it's made any difference

 

[Munkul]

But does that not mean that the feedshaft and screw cutting box are out of alignment? Also if they turcited the tailstock that will be higher than the headstock?

The saddle will sit slightly lower too and the tailstock height is yet to be set. I'll have to clock it and shim it up, as they left it low.

Edit : no I'm wrong. the saddle sits at original height. It need to sit relative to the screw cutting box that holds the shafts, which is dowelled and does not move. The headstock can happily sit lower, as its not connected to the screw cutting box other than by change wheels. But the centre height remains the same, since its the ways that are ground down, not the headstock itself.

 

[Brad93]

The saddle will sit slightly lower too and the tailstock height is yet to be set. I'll have to clock it and shim it up, as they left it low.

Right I see.
Would you of not been better sending the whole machine to them and having them rebuild it and test it, producing an test report?

If the tests indicate alignment is out now you can’t really blame the grind, because you’ll be the one remanufacturing it. Kind of got no warranty.

 

[Munkul]

Right I see.
Would you of not been better sending the whole machine to them and having them rebuild it and test it, producing an test report?

If the tests indicate alignment is out now you can’t really blame the grind, because you’ll be the one remanufacturing it. Kind of got no warranty.

That was my initial thought, before I learned anything about alignment etc. But budget price was twice as much! Not financially worth it.
With straight ways, the only thing I need to do is align everything. If it doesn't cut straight, I've only got myself to blame. Matter of fact, I'm not expecting it to cut straight first try anyway.
I've talked all of this through with Brian at Blue Diamond, and also Clive on here, so I've got a plan in my head and know everything will go back together relative to each other with no height mismatches. Its then on me to get it aligned properly.

It's all more simple than it first sounds, but of course it all takes time and patience too, and a steep learning curve for me!

 

[daedalusminos]

Watching with anticipation, I'll probably be going a similar route with my M300 in the near future.
I'm assuming BD are pretty much the only good option for a bed regrind - not exactly local to me in Norfolk, what was their turn around time like?

 

[Shox Dr]

Underneath of the saddle will have been built up with turcite equal to the amoun they removed from the bed, to keep the apron inline with the lead screw etc, and the rack.
I would be surprised if they havent at least setup the headstock on the bed, as it sits on the v of the bed way. You cant adjust for twist, other than leveling the bed, and they should not be required if it has been fitted correctly to the base.

 

[Munkul]

Watching with anticipation, I'll probably be going a similar route with my M300 in the near future.
I'm assuming BD are pretty much the only good option for a bed regrind - not exactly local to me in Norfolk, what was their turn around time like?

4 weeks

 

[Munkul]

I would be surprised if they havent at least setup the headstock on the bed, as it sits on the v of the bed way. You cant adjust for twist, other than leveling the bed, and they should not be required if it has been fitted correctly to the base.

You could say it's a bodge, but that's just an opinion.

Anyway I know you did yours "properly" doing a full rebuild, and much respect but I'm doing the bare acceptable minimum to get this thing turning well.

I'm aiming for half a thou over 8 inch as a minimum. That means I have a thou of alignment to play with as bodgery. Some of that will come out with the jacking bolts adjusting the twist of the bed.
All I'm saying is, the "perfect" method isn't the only acceptable method.

 

[Shox Dr]

True but you have it striped down,its just as easy to do it correctly as not.
There should be NO twist in the bed After its been ground. Level the base, bed the bed on 3 points of contact, two at the HS one tail stock. Using P38 fill the gap, fit bed bolts and lightly tighten, remove excess p38 ans let cure, nip bed bolts up. Job done