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JTrama
02-03-2005, 03:22 PM
Have a 10x24 Emco V10 lathe. I was using some longer drills and it seems that the tailstock was drooping. I checked with a drill rod in a chuck (.001 runout at chuck edge) and it seems like the rod is drooping about .01 per foot when help by tailstock chuck. I rotated chuck 180 deg and this number was consistent. I also checked manual deflection and the weight of the rod versus stiffness is neglible to cause this much defection. Vertical alignment to headstock seems ok, cleaned taper, etc.

Any ideas or remedies?

kap pullen
02-03-2005, 03:57 PM
I wouldn't worry about it.
Centerdrill chucked up close and the long drill will follow path of least resistance.
kap

zl1byz
02-03-2005, 05:08 PM
Viagra?

John.

Alistair Hosie
02-03-2005, 05:12 PM
can I have some?

egpace
02-03-2005, 06:29 PM
JT,
Check the bed for flatness! If you bolted the lathe down to a bench top that bows down in the middle, your bed could be swaybacked like a horse. Get a straight edge that spans the length of the bed & check it with feeler gages. If a gap is present, try loosening the mounting screws & see if if goes away. You can also use shims to bring the bed in. Better yet, get a new bench top.
Ed

JTrama
02-03-2005, 07:11 PM
Checked bed with best edge I have and it is within .002 or so over 24". It is on a solid table, etc and was leveled in originally. It is slightly low in center but not .01 over 12"!!!! With a 12" Sheffield square I cannot get anything under edge.

I worry about this because my drill bits are wobbling and my holes are oversize.

Yeah, I know - use less viagra.

Just wondered if I should;
1. Mill the base down to compensate for angle? IE give the tailstock some Viagra!
2. Use a MT2 reamer to true up the tailstock?

or..............

JT

egpace
02-03-2005, 07:19 PM
Before you mill the base down, take it on a surface plate & check with an indicator to see how paralell the tailstock ram is to the base. While you have it off, remove the ram, place in on vee blocks, rotate it & see if the taper is concentric to the od. Then take the tailstock chuck & do the same. Maybe your taper shank is bent. Dropped? Better yet, chuck it in a rotating spindle & see if it runs out.
Ed

JTrama
02-03-2005, 07:31 PM
Tailstock baseplate appears parallel (measured thickness beth ends).

I checked the droop with a rotating chuck and 2 different drill chucks. Pretty consistent through 3 different tapers.

Ram seems ok (have not measured) - but no binding or other issues.

What if I clamp the tailstock upper to a table and put rotating chuck with rod in it and check heights at chuck versus rod end? That would eliminate lathe bed, tailstock base, etc?

JT

Elninio
02-03-2005, 07:46 PM
maybe its the way your tailstock is held to the bed, theres like a little lever or sumtin, also just centerdrill the workpiece and the long drill will go strait.

beckley23
02-03-2005, 09:53 PM
On page 18, Sep/Oct '04 HSM, "Reconditioning a Lathe- Revisited", is the test card for a lathe. Run tests 10, 11, 12 & 13 to check your tailstock spindle. You could have several problems; the base is worn, bad spindle, worn spindle and/or bore.
Harry

Thrud
02-04-2005, 02:03 AM
Make sure that the ram is lightly clamped - if it is too loose, it can cause some problems with a tailstock that is a bit loose from wear. It is also possible that the bore has warts & pimples in it and do not allow the taper to seat properly - this can cause slight rocking as well.

If you get a finishing reamer to do this be aware that the tailstock spindle is hardened (on mine at least) and may dull the reamer badly - a small price to pay for a good fit. You can check the progress as you go by using a fresh MT#2 arbor - chalk it up and check for fit (or use prussian blue),

Also check to be sure that it is indeed centered and not slighly offset. There is not a lot that can go wrong on these machines...