Hafco AL336 not cutting straight

warrjon

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Looking for a second opinion. I suspect the head stock is not lined up down the bed. I do not think it's cross slide as I have faced 3" aluminium and if the cross slide was not perpendicular to the ways I would machine a concave especially with this amount of slew nearly 0.10mm or 0.0035".

My lathe is adjustable but I decided to sleep on it before diving in and adjusting the head stock.

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Two things could in theory make you face concave (or convex),one is the cross slide not perpendicular to the ways, the other being the spindle not parallel to the ways. My bet, especially if your headstock is adjustable, is the headstock itself
Mark
 
On my new 1340gt I was getting a taper, .005" over 5", spindle nose has less than .0001, ways were perfect, chuck was great.

I had to adjust the headstock. Put a 1.75" x 13" steel rod in chuck, stuck out 10" and trued the rod.

Moved the headstock a little at a time, very tedious and time consuming, because I took a .006" cut after every adjustment.

After 4 hours the taper was down to less than .0002" over 5"

If you put a dial indicator against the end of the rod it helps in adjusting. Very small movement .010 and less is best.

Don't use the tailstock.

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Thanks Guys,

Yes the head stock is adjustable, but as with anything I have to pull the motor off to get to the adjusting bolts and the pulleys and gears off to get to the back mounting bolts. I'm beginning to regret selling my Sheraton 9", it cut straight less than 0.001mm over 250mm.

Oh well a little time on this and we'll see how it goes. This has not been a trouble free lathe it's on its 3rd motor. I can not sell it to some other poor person either as I would not sleep.

cheers
Warren
 
Thanks Guys,

Yes the head stock is adjustable, but as with anything I have to pull the motor off to get to the adjusting bolts and the pulleys and gears off to get to the back mounting bolts. I'm beginning to regret selling my Sheraton 9", it cut straight less than 0.001mm over 250mm.

Oh well a little time on this and we'll see how it goes. This has not been a trouble free lathe it's on its 3rd motor. I can not sell it to some other poor person either as I would not sleep.

cheers
Warren
I had to remove the drive belt and slightly lower the motor each time I made an adjustment. 7 Bolts were all easy to get to. Even so, it took hours to zero in.

Probably a full day or two for your set-up.I did power up the lathe after each adjust and take a cut; if you could figure a way to measure without having to re-install the gears and motor?
 
I spent yesterday afternoon adjusting the headstock, I used the Rollie's Dad's method, which I have never heard of before. I worked great in less than 2hrs I had it cutting 0.00078" over 5". It was better but I think the head stock moved a little when I tightened the bolts so now I know how the adjustment works I'll have another go this coming weekend.

I had to do the adhustment about 20 times as the headstock rotates at the back so you can not subtract the 2 measurements. Also there are 4 adjustment bolts 2 pull on the headstock and 2 push so they need to be tight against each other this way I think the headstock will not move when I tighten the bolts.

Anyway thanks ALL.
 
Yesterday I tweaked it a little more it now cuts parallel.

I am still not very happy with this machine it faces concave which is not an easy fix. I faced a 300mm brake disc and on the surface plate it is 0.06mm from outer to inner. I'll have one more attempt at getting this thing to an acceptable level of accuracy before I ditch it.

I have spent more time trying to tune this thing up than making what I need. I will never buy another Hafco product.

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Just curious - are you using carbide tooling for your tests? If so, that can confuse things because of the deflection the tool produces at small depths of cut. Might want to try a sharp HSS tool instead.
 
Yesterday I tweaked it a little more it now cuts parallel.

I am still not very happy with this machine it faces concave which is not an easy fix. I faced a 300mm brake disc and on the surface plate it is 0.06mm from outer to inner. I'll have one more attempt at getting this thing to an acceptable level of accuracy before I ditch it.

I have spent more time trying to tune this thing up than making what I need. I will never buy another Hafco product.
Should be .01mm or less
 
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