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View Full Version : Fitting a D nose face plate?



torker
12-20-2008, 09:01 AM
Uncle Pete's thread got me thinking... I never did get my faceplate fitted on my lathe.
It came with the machine but it was obviously never tested at the china factory...it won't fit.
The taper on the faceplate doesn't match the taper on the spindle.
I've been putting this off because I still haven't found a good way to mount the faceplate to turn the taper out.
Of course...it has to be mounted or held...backwards with a four jaw somehow.
Then you'd have to tear the whole setup down, take the chuck off, etc....how many times for trial fits etc.
I'm wondering...would it be better to somehow scrape this taper and use blue to keep testing it with?
The taper is inside the hub (obviously) and down in there about 1 1/2".
I'm assuming that this taper is the way a D nose chuck or faceplate is centered?
It doesn't need much taken off...it ALMOST fits but not quite. any ideas? Thanks!
Russ

BadDog
12-20-2008, 09:28 AM
Scraping that much would not appeal.

Perhaps bolt something like a pipe flange to the face plate, and then grab the hub in the 4 jaw. Get it nice and square/concentric, dial the taper to perfection (VERY short) using the compound, dust off. Remove as a unit for test fit. But be careful, that is a very short fairly slow taper, taking off more than a tiny bit may make it far too big (I know you know that, but had to say it :D)...

torker
12-20-2008, 09:43 AM
Russ...that's what I'm afraid off...be pretty easy to take off a whisker too much. Good idea on the pipe flange.

John Stevenson
12-20-2008, 09:53 AM
The taper is inside the hub (obviously) and down in there about 1 1/2".
I'm assuming that this taper is the way a D nose chuck or faceplate is centered?
It doesn't need much taken off...it ALMOST fits but not quite. any ideas? Thanks!
Russ

1 - 1/2" ??


http://www.workholding.com/BISOND-1SPINDLECHART.jpg

Depending on what size it is it can only be 7/16" to 5/8" deep.

Because it's a very short taper it's hard to dial in.
Best way is to use a parallel bar in the chuck, set the top slide to a tad over 7 degrees and zero a dial gauge at a point on the bar.
Now advance 1" on the top slide and the dial gauge should read plus or minus 0.124" depending on which way you have the top slide pointed.

That's the taper.

Now for fit it is best to make a short dummy spindle nose up, turning at this setting unto a known chuck or backplate fits exact.

Note you can keep the setting of the topslide to do intenal or external if you turn the boring bar over and still cutting in forwatd take the cuts off the back of the work.

This way you get to keep the exact taper.

Sounds long winded but it's actually quicker than it sounds.

Incidentally the taper on the D series is exactly the same as on the European A series and provided you can get frest studs in they are interchangeable

.

Bob Ford
12-20-2008, 10:05 AM
First set your compound using a test indicator on the compound. Indicate the back side of the taper. Now your compound is ready to cut the taper on the faceplate. Mount faceplate and using test indicator see how bad it is then you know if you want to take a cut. You might also take measurements of small end, large end and length of the taper in the lathe. This would tell you if a duplicated taper would be too small.

Bob

BadDog
12-20-2008, 10:08 AM
By "down in there", I think he means he has one like one of mine. Some are only maybe 3/4" or less deep, and that's it. But I've got one with a rear bore at least 1.25 deep, and the taper extends for near an inch (or so memory says) even though it seats on only half the taper. I figured he meant he had one of the latter.

And speaking of A/D similarities, I just ran into that. Long story, but I wound up with an A6 Jacob's Rubberflex chuck that had a D1-6 back plate. The back plate had been modified with an A6 face! Stacked run out was unacceptable, so now I'm trying to sell an A6 chuck (anyone?). But while fooling with it, I got to see first hand the similarity. And apparently some folks just mount 3 pins to convert.

torker
12-20-2008, 10:09 AM
Geez...John you are right. I was just looking at it hanging on the wall last nite...the hole IS 1 1/2" deep...but the taper is only maybe 1/2" long and would be on the outside if the plate was mounted backwards.
Went and complicated things before I even got going :D
Yeesh...I'm going to be waiting a bit...it is REALLY cold in the shop..LOL!
I have a bucket of water sitting about in the middle of the floor. It's frozen down about 2". Turned the stove down a bit too much for -30 I reckon.

BadDog
12-20-2008, 10:12 AM
First set your compound using a test indicator on the compound.

Bob
For the "short taper" spindles, even the ones this size, the taper is SO short, you could be off by an unacceptable amount and still barely twitch a tenths indicator. Probably ok, but depends on how "good" you are at indicating.

A better solution might be to set it close with indicator, then turn a full compound travel taper in a piece of scrap. Then measure carefully and compare against the standard. The long cut would magnify any error. Tweak until you are within acceptable tolerance, THEN mount and square/center the face plate for the taper adjustment...

John Stevenson
12-20-2008, 10:18 AM
BD,
The D and A taper is 0.124" in 1" of topslide travel, that's long enough to get a good reading.
It's also easy to remember as if you say 1/8" over 1" the odd thou won't matter if you are polishing to a fit.

.

BadDog
12-20-2008, 10:23 AM
Agreed, if you've got a 1" long standard to check. Perhaps dial a sine bar?

But I was mostly thinking in terms of difficulty measuring and quantifying cut tapers with extreme accuracy. By turning one 3" long or so, errors in measurement are also reduced. But I suppose 1" long, with a high resolution and good/accurate DI, carefully set exactly on center, with 1" axial travel measured exactly with another DI on the bed (or DRO), and that should easily be good enough.

Oh well, brain getting foggy, been up half the night with leg pain. Time to go see if I can get another bit of shut-eye while the day warms a bit...

John Stevenson
12-20-2008, 10:26 AM
Agreed, if you've got a 1" long standard to check.

No put a parallel bar in the chuck, zero a DTI at one point on the bar, then travel the TOP slide that is set over to just over 7 degrees for one inch the DTI should read 0.124"

Adjust the top slide setover to suit.

.

TGTool
12-20-2008, 12:42 PM
Torker,

Dunno what you've got there to use with mounting the faceplate, but on my four jaw, I can take all the jaws out, then use the jaw slots for T-nuts as though it were another faceplate. In that case, you can mount the two chucks face to face and dial in.

torker
12-20-2008, 02:00 PM
Thanks guys!
TG...that's pure genius. I've never heard that one before.

BadDog
12-20-2008, 03:18 PM
Oh wow, talk about can't see the forest for the trees!!! Thanks for clearing my head and pointing out the obvious!

Edit: One thing, wouldn't that be 1" along the axis? So you would need to trig out either a slightly different opposite side, or different top slide travel (hypotenuse).

John Stevenson
12-20-2008, 06:07 PM
No the one inch is calculated along the top slide.
Along the bed would be 0.992"

.

oldtiffie
12-20-2008, 07:18 PM
http://www.workholding.com/BISOND-1SPINDLECHART.jpg

..........................

Because it's a very short taper it's hard to dial in.
Best way is to use a parallel bar in the chuck, set the top slide to a tad over 7 degrees and zero a dial guage at a point on the bar.
Now advance 1" on the top slide and the dial guage should read plus or minus 0.124" depending on which way you have the top slide pointed.

That's the taper.

Now for fit it is best to make a short dummy spindle nose up, turning at this setting unto a known chuck or backplate fits exact.

Note you can keep the setting of the topslide to do intenal or external if you turn the boring bar over and still cutting in forwatd take the cuts off the back of the work.

This way you get to keep the exact taper.

.......................................
.

Good pic, good post John.

Just a couple of thoughts.

7 deg 7 min 30 sec is 7.125 degree, the TAN of which is 0.125 which is a taper of 1:8 = 1/8" per inch which is 1 1/2" per foot on radius. The equivalent distance along the "slope" is COS 7.125 = 0.9923 or 0.125 X 0.9923 = 0.1240" as you say.

There are many ways to set the taper accurately.

My main concern is that given that in your pic/sketch that the dimension "B" has a a tolerance range varying from 2.1250/2.1255" (0.0005" limit) for a D1-3 flange to 11.2510/11.2520" (0.0010" limit) for a D1-15 flange.

The location is both on the tapers and the flange faces of the mating parts (ie lathe flange and chuck/face-plate).

Measuring that dimension "B" is going to take some doing.

Another way of stating the 1:8 taper is that for every 0.001" that is turned off, the (end of the) taper will move 8X that amount ie 0.008"

The quality of the surface finish will be an issue as well.

These are very tight tolerances for a lathe and not too easily done on a good universal grinder either.

I think I'd be aiming for a parallel section that ends with a shoulder 1/4" (0.250") out from the face and with a diameter of (B - (2 x (0.250/8))) = (B - (2 x (0.03125))) = (B - 0.0625) +0.0005/-0.0000" and turn the taper until there was just the barest "witness" of that diameter left showing.

I'd imagine that the setting of the angle will be pretty critical as well - perhaps 7.125 +0.003/-0.000 degree or + 10 arc seconds/- 0.00 arc seconds which suggests an accuracy of 0.0005" per inch or better.

I wouldn't be too concerned about the bore of the face-plate but I would be concerned that a "wrongly" bored face-plate may not do much good for the spindle mating surfaces which have to retain their accuracy to locate any chuck or collet adaptor etc. that may be mounted on the taper and rely on it for accuracy.

Perhaps I am too "Tool-room orientated" - perhaps not.

John Stevenson
12-20-2008, 07:59 PM
My main concern is that given that in your pic/sketch that the dimension "B" has a a tolerance range varying from 2.1250/2.1255" (0.0005" limit) for a D1-3 flange to 11.2510/11.2520" (0.0010" limit) for a D1-15 flange.

The location is both on the tapers and the flange faces of the mating parts (ie lathe flange and chuck/face-plate).

Measuring that dimension "B" is going to take some doing.



This also has to take into account that EVERY spindle out there falls within these tolerances.
You are only interested in one taper and that's the one on your lathe so make a dummy spindle nose and work to that.

.

oldtiffie
12-20-2008, 08:15 PM
Agreed entirely John.

But .......................

The diameter of that "dummy spindle nose" has to at least match and preferably be better than the standard for "B" and that is going to take some doing unless another "female" is used to "blue-in" the "male" "dummy spindle nose" "taper" and its OD at the "face".

In the ideal state, this is coming very close to precision machining at its best.

I don't doubt for a minute that you can do it and have done it, but it is not as "simple" as some others might think.

But having said that, it is certainly "do-able" by just about anyone on a fair to good lathe, but it all depends on the accuracy and functionality required - and hopefully - achieved.

torker
12-20-2008, 09:14 PM
You guys have me all mathed out now.
I'm wondering...why can't I put a TDI on the compound...and set the angle for it with the TDI on the far side of the nose taper itself?
Oh...and don't forget...I've done a lot of work on a lathe...but I still don't know anything much about really precison stuff.

John Stevenson
12-20-2008, 09:28 PM
You guys have me all mathed out now.
I'm wondering...why can't I put a TDI on the compound...and set the angle for it with the TDI on the far side of the nose taper itself?
Oh...and don't forget...I've done a lot of work on a lathe...but I still don't know anything much about really precison stuff.

You can if you are careful but the taper is very short and it's hard to get an accurate reading over a short taper.

Knowing how clumsy you are with rear plow mounts you don't stand a cat in hells chance :D

.

BadDog
12-20-2008, 10:36 PM
Hehe, no kidding! ;)

As already said, it's the very short travel that causes a problem. You could be out by 0.002 in 1 inch, quite a bit for this stuff, and it would be hard to see with a typical DTI on a 1/2" taper, given that you are likely to only be able to manage about 3/8" stabilized travel. So you put a 0.0001 indicator (or smaller, 0.00005 if ya got it!) and small ball on short arm, then set it so that it does not even twitch, and then verify it on a different part of the taper. That's likely "good enough", so so says my limited experience...

torker
12-20-2008, 11:47 PM
LOL! Good one John....
actually...I had more in mind of holding something tight up against the taper that's longer. That should cut down on the chances of me dropping the lathe on myself..