Trials and tribulations with a 7x12 lathe

Gallery, Projects and General > Project Logs

<< < (11/12) > >>

cfellows:
So, exactly how are you adjusting the headstock to take out the two tapers?

Thx...
Chuck

modeldozer:
Hi Chuck,

So far only busy with the vertical, and this one is lower at the tailstock end, am shimming under the lefthand of the headstock (front and rear). Am using aluminium foil as shims. The procedure for testing is known as "Rollies dads method" and is on the toolandmods site.

Abraham

cfellows:

--- Quote from: modeldozer on June 18, 2011, 04:05:41 AM ---Hi Chuck,

So far only busy with the vertical, and this one is lower at the tailstock end, am shimming under the lefthand of the headstock (front and rear). Am using aluminium foil as shims. The procedure for testing is known as "Rollies dads method" and is on the toolandmods site.

Abraham

--- End quote ---

Thanks, Abraham. I'm familiar with the "Rollies Dad's method", but just wonderered if you shimming or scraping. I think my lath also has some slight headstock alignment issues. Hasn't been a problem so far because I do mostly pretty shallow work with it. But I may have to make adjustments at some point.

Chuck

modeldozer:
Hi all,

Been at aligning the headstock for three days now, aaand just as me thought me had it nicked ... decided to verify it at varios locations along the travel. The bed is bent badly in the horizontal :( From the chuck the first 80mm is good and then in the next 80mm it tapers back 0.1mm.

Two options I can think of now:

Buy an new bed of unkown "straightnes"
or have this one reground, for this i will need to locate a machine shop with the right equipent/experties and most probably expencive. GRRRRRRR. :bang: :bang: :bang:

As a side note, have located a major sorce of non rigidity in the bed, the part where the headsock bolts on is only supported at the front and left side and it litarly bends by just resting a hand on the headstock. Found this by chance while checking the alignment, Di was moving as I was moving my hand so I investigated a bit and with the DI between the top of the rear foot and the underside of the headstock, with only light pressure on top it deflects 0.02mm. Will need some invetigation for a cure.

Sad :( and frutrated :bang:

Abraham

loply:
Hi Abe,

So are you saying the V in the bed is not straight, causing the saddle to move away/towards the spindle axis at different points?

Could you identify the areas where the bend occurs and simply scrape them flat? If the 'V' is machined with a 'bulge' on one side this would work, else you would end up with a V which is thinner in spots than others, but it may still be fine, you would just loose contact on one side of the V for the duration of that spot - not ideal, but better than a 0.1mm bend!

Alternatively you could scrape the entire V to a thinner shape and remove the bend, but you would end up having to re-fit the saddle quite a lot?

Rich

Navigation

 Message Index

Go to full version