Tap drivin' man (tap driver in AXA holder?)
Louis Ohland
driver on a lathe? Assuming the gears are correct, could you use the feed?
ignator
> What is the common wisdom on the results of using a tap in a tap
> driver on a lathe? Assuming the gears are correct, could you use the feed?
I've done it using the tail stock (with 3 jaw chuck), and putting the
lathe in back gear. I've only tried the quick change for long boring
bars, but never a tap. Tell me how you know it's perfectly concentric
both vertical and horizontal?
ignator
Buerste
"Louis Ohland" <ohl...@charter.net> wrote in message
news:BsXnn.101625$Ye4....@newsfe11.iad...
> What is the common wisdom on the results of using a tap in a tap driver
> on a lathe? Assuming the gears are correct, could you use the feed?
I will often put a tap in a drill chuck but not very tight and leave the
tailstock loose. Great for starting a tap. I have a tapping head in a
turret lathe that will spin the tap before breaking it and it's spring
loaded to compensate for feed.
Don Foreman
wrote:
> What is the common wisdom on the results of using a tap in a tap
>driver on a lathe? Assuming the gears are correct, could you use the feed?
You can, but a tap once started pulls the tail stock along just fine.
I just sorta bonk the tailstock-mounted tap into the hole with the
lathe running. The tap catches and the hole gets threaded. Problem
with using power drive on the tap is if the stock slips rotationally
in the chuck or collet then the tap must drive the stock axially in
the headstock workholder or something must get barfed up or break.
Karl Townsend
> on a lathe? Assuming the gears are correct, could you use the feed?
I do this in my CHNC Hardinge. (CNC lathe) The taps last far longer if
everything is rigid. A CNC lathe has virtually no backlash, if your machine
has backlash, I could see trouble when reversing to back out.
I also do rigid tapping in my CNC mill. again, the taps last far longer. In
fact my first job after coffee is drill and tap a dozen holes in a part I
mounted up last night,
Karl
Robert Swinney
might be a bit of overkill. Sensitivity would be better served and give you more of the tapping
experience if you put the spindle out of gear and turned it by hand. I have an outboard crank on
the spindle which I use with this method.
Bob Swinney,
"Louis Ohland" <ohl...@charter.net> wrote in message news:BsXnn.101625$Ye4....@newsfe11.iad...
Louis Ohland
the lathe only goes down to 150rpm.
Robert Swinney
I only mentioned hand cranking of the spindle as a means to achieve max control when tapping in the
lathe. For me, it makes a good diagnostic approach when trying to isolate threading problems in the
lathe, both single-point threading and tapping. As far as procrastination goes toward making an
outboard hand crank, don't make a crank. First try it out by hand turning the chuck with the spindle
out of gear. The lead screw will still advance just as if things were in-gear.
If you decide to make a crank, I recommend obtaining a tail-pipe expander (HF) as a means to easily
insert / remove the crank from the hollow outboard end of the spindle. I have 2 of these. One fits
the spindle bore and the other fits my 5-C drawbar.
Bob Swinney
"Louis Ohland" <ohl...@charter.net> wrote in message news:d65on.523$gF5...@newsfe13.iad...
Jon Elson
> "Louis Ohland" <ohl...@charter.net> wrote in message
> news:BsXnn.101625$Ye4....@newsfe11.iad...
>> What is the common wisdom on the results of using a tap in a tap driver
>> on a lathe? Assuming the gears are correct, could you use the feed?
>
> I do this in my CHNC Hardinge. (CNC lathe) The taps last far longer if
> everything is rigid. A CNC lathe has virtually no backlash, if your machine
> has backlash, I could see trouble when reversing to back out.
in the long gear train that there is no way at all to reverse the lathe
to back the tap out. In many cases it will be more than half the thread
pitch off, so either the tap will break or the thread will be destroyed.
You could use the threading feed to advance the tap, but you'd have to
release something to allow the backing out.
Jon
Louis Ohland
> Karl Townsend wrote:
>> "Louis Ohland" <ohl...@charter.net> wrote in message
>> news:BsXnn.101625$Ye4....@newsfe11.iad...
>>> What is the common wisdom on the results of using a tap in a tap
>>> driver on a lathe? Assuming the gears are correct, could you use the
>>> feed?
> release something to allow the backing out.
The first thought was to release the half nut, but that does nothing for
the lathe rotation... Think of it as a rota-bur...
John
> What is the common wisdom on the results of using a tap in a tap
> driver on a lathe? Assuming the gears are correct, could you use the feed?
The best way I found to tap in a manual lathe is to let the tail stock
float unclamped feeding in with the tailstock handle. I use morse tap
collets that hold the tap rigid in the tailstock. I never had a problem
with broken taps. You could use a different tap holder or even a
jacobs chuck to hold the tap but then tap slippage becomes a problem.
When you feed in with the tailstock wheel it will tend to pull the tap
in on its own, you just have to keep a little pressure on the handwheel
to take up the movement of the tap feeding in. The tailstock itself
will move with the tap but by turning the wheel you try to keep that
movement to a minimum.
John
DoN. Nichols
> What is the common wisdom on the results of using a tap in a tap
> driver on a lathe? Assuming the gears are correct, could you use the feed?
What do you mean by a "tap driver"?
I use taps regularly in a releasing tap holder in the bed turret
on my Clausing. Feed is by hand using the spider, and as soon as the
tap digs in, it pretty much self feeds, and you are simply following it.
When you reach the preset stop on the turret station, the
spindle keeps turning and pulls the tap about 1/8" or so to disengage a
dog clutch and allow the tap and its holder to spin freely. Then I stop
the spindle and reverse it to back the tap out.
If you mean something like a TapMatic self reversing tapping
head, that depends on the shank of the TapMatic (or other brand)
rotating to power the tap forward and in reverse as the dog clutch
releases the direct drive and engages the planetary gear to reverse the
tap as you pull back.
If you mean a *rigid* tap holder, you may have problems stopping
the spindle quickly enough to avoid overrunning the depth (in blind
holes) or running up on the unthreaded part of the tap on through or
deep blind holes. You need something which will release as soon as the
carriage stops moving like a releasing tap holder for a turret lathe or
automatic screw machine.
eBay auction #14016680222 is an example. This one has a 1"
shank, which I think is larger than the boring bar holder for the AXA
toolposts. I think that they limit at 7/8" or 3/4". Check yours.
But they have gotten a *lot* more expensive on eBay from when i
was buying mine.
Aha! Here is a 3/4" shank one and it is even selling for
somewhat less: Auction #310186077480
Anyway -- some of them just release, and you need to use the
friction while drawing back on the tap holder to back the tap out.
Others have a built in ratchet which lets it lock up when you reverse
the spindle. But be careful to check before you use, as the ratchet
direction is reversible by disassembling the holder and moving a part.
Enjoy,
DoN.
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