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hadjcues
08-09-2004, 04:15 AM
I'm having trouble aligning my tailstock vertically... it's a couple of thousandths inch
lower. This would not make me drill holes true to center. I plan to jack it up with brass shims... is this acceptable?

I'm considering making an adjustable live center where I could adjust the vertical axis to allign it.

Any suggestion guys?

SGW
08-09-2004, 08:13 AM
Sure -- I assume you're putting the shims in between the top and bottom pieces of the tailstock. Ought to work fine.

The adjustable live center sounds like more trouble than it would be worth to me. Just shim it.

Forrest Addy
08-09-2004, 10:22 AM
I assume you're tramming in the tailstock quill from the head stock. Before you make any adjustments be sure your indicator set-up is rigid and the tailstock has no "rocking chair" in the fit between it and the bed and the quill travel is paralle to the spindle axis.

If you're confident of your readings and any indicator sag has been accounted for go ahead and shim as appropiate.

FWIW, a little tailstock misalignment has little effect on the straightness of drilled holes provided the drill got a straint start. If I'm concerned about obtaining a straight deep hole I drill a starter hole a little undersized at least three diameters deep and bore it to the hole diameter to ensure a concentric start. I've drilled 5/16" holes from both ends of 5/8 dia CRS 20" (hard way to make 3/8 IPS Sch 80 pipe) long to meet in the middle and seldom had over 1/64" error.

[This message has been edited by Forrest Addy (edited 08-09-2004).]

Paul Gauthier
08-09-2004, 10:49 AM
Be sure that your bed is level first or your tailstock will only be trammed in where it was sitting on the bed, once you move it from that position it will be out again.
And FWIW a couple of thou just ain't worth the trouble.

hadjcues
08-11-2004, 01:43 AM
Thanks for the reply guys...

I have no problems drilling a straight hole but the tolerance for drilling a hole on cues should be dead on and I mean dead center and concentric with the shaft or dowel.

A thousandths off, little as it may seem will not give out a straight cue.

I'll try putting on the shims, but it's a lot of work... assmbling and disassembling the tailstock... aaaahhhh....

Before I go, I plan to put a rear chuck on my lathe, a 3 jaw self centering preferably with a 1 3/8 - 1.5" through hole. Any online link which gives value for the money?

Evan
08-11-2004, 02:11 AM
Hadjcues,

Don't make more work for yourself than necessary. You are drilling wood. You can't hold .001" tolerance in wood. It's hard enough to do in metal. Just what do you mean by "rear chuck"?

If the tailstock is a couple of thou low it is not going to make the hole off center, it can't. The work is rotating, not the drill bit. In wood all that will happen is the hole will be slightly larger if the drill bit is low a couple of thou.

hadjcues
08-11-2004, 02:53 AM
EVAN,

Thanks for the reply... How would I remedy this problem and what causes it.... when I drill a hole or try to locate a center of a dowel on the lathe using my tailstock. When I measure the hole. 5/8" or 3/4" it is not center of the round stock. Meaning when I measure a dowel with a hole... one side tends to be larger than the other. I interprt this as the hole is not perfectly centered but it's straight. I see this as a result of the tailstock being abit higher than it not being centered. Btw,if the tailstock is centered but is a little bit off vertically would it result in these off center holes?

hadjcues
08-11-2004, 02:57 AM
REAR CHUCK

its the same chuck as in the head but just located at the rear end of the spindle bore. So having 2 chuck at both ends of the spindle bore allows to hold longer work

Forrest Addy
08-11-2004, 03:13 AM
That's a handy accessory Hadjcues suggests. You see them a lot on oil country lathes and hollow spindle lathes used in hydraulic shops for machineing long cylinder rods. I had a beater on my lathe but I neededit worse on a home made weld positioner I later sold.

BTW don't be shy about boring out the ID of a cheap three jaws chuck if there's a need to. The bodies are machinable and there's usually plenty of meat before you run into the scroll.

Tomzhere
08-11-2004, 07:27 AM
If you look closely at this picture you can see the 3-jaw at back of machine.

You will have to make an adapter for it to fit your spindle threads, also consider making index holes in your adapter. I think you will know how to use them.

http://www.tkscues.com/13x40Photo.jpg

Hadj, Joe has one for ($99) cheap as I have found. I'd jump on it if you really want one.

Tomzhere
08-11-2004, 07:36 AM
Hadj, one other thing. I think I might have mentioned this to you before. This is what I do and it works great.

If you invest in a QC tool post then you could get a QC collet holder and collet(s) for your drill size. Then you could use your carriage and feed to drill.

The QC tool holder is easily adjustable for center height. You could also get the QC holder with a Jacobs type drill chuck already on it. The collet type might be a little more accurate though.



[This message has been edited by Tomzhere (edited 08-11-2004).]

ERBenoit
08-11-2004, 08:22 AM
If you uce the QC set-up you must be very careful in your set-up. If you are slightly off center in any axis, or the drill is not perfectly aligned with the spindle you may end up with oversized, tapered or bellmouthed holes.

Evan
08-11-2004, 09:25 AM
Hadj,

One of the greatest differences between wood and metal is that in wood the average properties of the material are not at all well localized. This means that you will experience varying density, you have different strength with and against the grain and there are density inclusions like knots etc. This will cause unexpected results when machining wood. When drilling a hole with a 5/8" bit it isn't at all likely the bit is going to wander, it's way stronger and stiffer than the wood. If it is .002 low or high it will just act to bore a slightly oversize hole. I would verify this by placing a block in the chuck and drilling it cross grain, then see what size it is.

Paul Alciatore
08-11-2004, 11:34 AM
I don't know what kind of wood you are using but what Evan said about grain and knots and differrent densities is true. I have found that drills will wander between the rings. Summer/winter (I forget which) parts of the rings are harder and it is extremely hard to get the drill to start anywhere except the softer areas in between.

The self centering action of drilling on a lathe will not help because the drill will flex. Also, if the tailstock has any play in it the whole drill-chuck-taper-tailstock spindle will rotate and allow the tip of the drill to move several thousanths. As the work rotates, the tip of the drill will rotate with it, producing an off center hole.

Yes, do center the tailstock. But you may also have to try other things. One possibility would be to purchase machine screw length drills or even shorter ones (resharpen them as short as possible). The shorter drill will not flex as much and will also lessen the movement due to tailstock play since it has a shorter radius of action. You might try using center cutting milling cutters. I don't know how well they will work on wood but it's worth a try. The idea here is that they do not have a center point that attempts to steer the drill. When they hit a hard spot it will simply push in an axial direction and not sideways. You also might try a boring bar. Think short, stout, and no point.

Paul A.

John Stevenson
08-11-2004, 11:51 AM
<font face="Verdana, Arial" size="2">Originally posted by Evan:
Hadjcues,

Don't make more work for yourself than necessary. You are drilling wood. You can't hold .001" tolerance in wood. It's hard enough to do in metal.

</font>

All bored holes on piano actions have a plus 0.0005" minus 0.0000" tolerance.
Some parts, like wire flanges and stem flanges come off production machines at the rate of 17,000 to 18,000 pieces per day



------------------
John S.
Nottingham, England

Tomzhere
08-11-2004, 12:14 PM
Hadj, I agree with Evan that drilling (boring) a 5/8 or 3/4 hole in tight strait grain Maple or even the dense exotics should produce a hole that is centered in the dowel. Just the same as boring would.

A very small diameter drill that contacted the wood off center may continue to drill an off center hole. However you should see the end of the bit wobble as it bores/drills. Short stiff bits are best for this.

Have you checked to see that the tailstock quill is parallel with the spindle centerline? Verify it by indicating it in the retracted position as well as the extended position?

If not, the resulting hole that you drill by extending the quill could be at a slight angle (and possible bell shaped) to the chuck/spindle center and anything (tenon) inserted into it may also then be at an angle. Thus when you put the two pcs together they will runout badly.

You could be drilling/boring the hole at a slight angle. When you measure the wall thickness be sure the caliper is at right angle to the center of the dowel and look for any gap at top of caliper blade on either side.

If you have one of those test indicators with the bent tip try using it at bottom of the hole (or as far in as you can get) to see if you are running out.

[This message has been edited by Tomzhere (edited 08-11-2004).]

Lee
08-11-2004, 02:00 PM
I work with wood quite a bit and one thing it isn't is predictable. It is always a crap shoot. This is why to get real good at wood working you have to be great at fixing and hiding your mstakes or you could go to the poor house in short order.
I was thinking abot your problem. There are some good ideas here. I have never thought about a second chuck in that location. Thats neat.
What I was thinking about is you drill a hole in your raw stock first. Then using your brass threaded spindle, center it up and turn down the outside diameter. This is of course, if you are turning this part yourself. Just thought that might help and give you more repeatably accurate results.


------------------
Lee

SGW
08-11-2004, 02:24 PM
I think the only way to be sure the hole is going to be where you're trying to put it is to bore it. Drills aren't for making precision holes.

dsergison
08-11-2004, 03:42 PM
I think what this guy might really want on the end is a nice cathead?

I did buy a small rotating 3jaw tailstock chuck once with a mt2 stub for a 9x20. it was sort of handy, but limited. would have prefered a nice cathead had I know of such things back then.

hadjcues
08-12-2004, 07:52 AM
Thanks guys for the reply...
I've taught about your suggestions guys... I'll be workin' my tailstock this weekend and try to shim it up and see how things work out.

I've been using this wood boring bit that seem to wobble guess that's why the holes ain't centered. I'll try to drill 3 sizes down and finish up with a boring bar to enlarge the hole. I'm pretty sure that would turn out straight... and centered

I'll try out using those mills suggested here, that could also work.

Tom, thanks for the advice! I've checked out some other sites that have those 3 jaw chucks and they're much cheaper than what Joe sells them out. And the 6-wing cutter he has there is like 10X more expensive than at a distinguished hardware site. Got the info from Willie of WillieCue.

Tomzhere
08-12-2004, 08:50 AM
Hadj.. who has the 3-jaw cheaper that 100 bucks? I'd be interested if it is the same one.

I did find where I can get the chuck with 7/8" through hole cheaper. Are you talking about the chuck with the 1 3/8 through hole? If so, can you tell me who offers it?

Yeah, I don't use the 6 wing cutter either. I use a side milling edge cutter for more cuts that is if I use my laminate trimmer.

I am doing something else right now though.

Tom

hadjcues
08-14-2004, 08:34 AM
Tom,

Yeah it's the one with 1 3/8 spindle bore. The link is in my PC and I'm still having my connections fixed. I'm using a public access computer now. I'll try to look for it and surf a little and I'll send you when I find it.

I bet you're using that table saw machine right? =) I wanna have one built for me but I still have to make a suitable design to fit my style or working. I'm currently using a trimmer with a spindle speed of somewhere between 75-80rpm and with a slow feed rate. I get real smooth cuts with it and needs very little sanding. I wanna have that table saw because it's not loud like a trimmer =)

Any suitable design for that you know? The current design that most CM's have takes up quite a space and the saw stays stationary I believe the shaft feeds into the cutter right? I believe it will be more stable and easier to control if it was the saw that glides along the shaft wood. JMO

I'm still working on it though...

kap pullen
08-14-2004, 09:03 AM
I'd like to have that tail-end chuck for jobs, but up to now just made a flanged bushing a neet fit in the spindle bore, and bored to fit the job at hand.
A lathe dog, or a set screw will hold it in place while machining

That's another use for duct tape too.
wrap it around your part until it is a neet fit in the spindle for a non-precision job.

kap



[This message has been edited by kap pullen (edited 08-14-2004).]

hadjcues
08-14-2004, 09:44 AM
kap,

Yeah that's what I've done so far. Made similar bushings made of that kind of hard foamy material they put on shoes. It's simple for me because I just have to bore out the desired hole diamter for the job.

I was thi8nking of putting that rear chuck and probly mount a bed on that side of the lathe just for use for finish sanding without any carriage getting in the way. A minor detail to consider is just making sure the tailstock is in alignment. Ofcourse the bed would be retractable 'coz that side of the lathe is where the engine compartment is.

Is this possible or has this been done before on lathes?

I also have this huge 3 phase motor running with the lathe with a 10" wheel on it. I got it as it is. Could a load be applied to it say a 8-10" circular saw blade?