Author Topic: Edgwick spindle taper adapter  (Read 9453 times)

Offline AdeV

  • Madmodder Committee
  • Hero Member
  • *****
  • Posts: 2229
  • Country: gb
Edgwick spindle taper adapter
« on: April 01, 2010, 06:04:25 PM »
Anyone following my sump build will have seen that I've just bought a nice new ER32 collet holder (with MT3 arbor) for the lathe. Unfortunately, the spindle taper adapter, as well as being very short, also suffers from some runout.

Sounds like a good excuse to make a replacement  :proj: While I'm at it, I'll make it a bit longer, so I don't need to take the 4-jaw chuck off the lathe when I want to use the collet chuck. Once I've made the spindle adapter, I'll have to knock up a drawbar, handwheel and collar for the other end of the lathe - as pretty much everyone said, I will need one to keep the collet chuck from wandering out of the taper & flying across the room.  :zap: 
:nrocks:
So; here we are with an 8" length of 2" leaded mild steel, all dialed in to as near as buggrit zero runout (maybe 1 or 2 tenths - it took a good hour just to set that up). I've set the top slide over about 3 degrees, but for the final checks I'm using the dial gauge and a known distance (1"). I've calculated the taper at 605 thou/foot - which works out pretty close to 50.4 thou per inch. The dial gauge only does thou divisions (eejit that I am, I've got a perfectly good Mercer dial in the cupboard which does tenths, should have got that out):



The only place I could get the dial gauge mounted up was on the side of the toolpost. I got it all as straight & level at the dial end as I could...

Anyway, quite a considerable time later, start cutting the taper:



Whilst it was in the chuck, and before I moved it, I decided to drill the centre hole; that way, it's definitely concentric with the taper. I'd already centre drilled for the live centre, so now I just drilled a 6.5mm pilot hole as deep as the drill bit, then a 10mm (same again), then:



That's my third longest drill, an 8.5" 1/2" beastie. A couple of weeks ago, I'd have been nervous as hell of putting that amount of drillbit through a hunk of steel. But now? Pfff. 8" is so small  :lol:

Thus, a short time later:



Time to hit it with the Dastardly Drillbit of Demonic Length!



That's not the longest drillbit.... that one is the 5 from eBay drillbit. It proceeded to munch through the steel like it was some kind of marshmallow, or something. So, less than 10 minutes later:



You can clearly see the length difference (at least, I hope you can!). So, time to slip the 4-jaw off, blue up the spindle & pop it in there with a light battering from the Plastic Hammer of Destiny:





Arse. The taper is too steep.


Just for reference, I popped the other one in & had a look at where that one blued up; it seems to do most of its gripping in the central portion, with less contact front & back... so, maybe the taper's actually 0.600"/ft - that would certainly make more sense than 0.605"/ft... Hey ho, tomorrow's a bank holiday at least, which means I get all day at it.
Cheers!
Ade.
--
Location: Wallasey, Merseyside. A long way from anywhere.
Or: Zhengzhou, China. An even longer way from anywhere...
Skype: adev73

Offline Andrew_D

  • Jr. Member
  • **
  • Posts: 44
Re: Edgwick spindle taper adapter
« Reply #1 on: April 01, 2010, 06:33:24 PM »
Just for reference, I popped the other one in & had a look at where that one blued up; it seems to do most of its gripping in the central portion, with less contact front & back... so, maybe the taper's actually 0.600"/ft - that would certainly make more sense than 0.605"/ft... Hey ho, tomorrow's a bank holiday at least, which means I get all day at it.

Do you know what the taper in the spindle is???

If it is 0.600"/ft, that would make it a Jarno taper I believe.

Less than 0.600" could be Morse or B&S.

Of course it could be something proprietary!  :doh:

Andrew

Offline Jasonb

  • Sr. Member
  • ****
  • Posts: 451
  • Country: gb
Re: Edgwick spindle taper adapter
« Reply #2 on: April 02, 2010, 02:51:52 AM »
Did you have the DTI spot on ctr height, anything else will give a false reading. Also take a DTI reading on the taper after machining to make sure it reads zero all the way, the cutting force will move the topslide a fraction if there is any movement in the ways.

When you recut the taper leave it in the chuck and take the whole lot off to test fit, though if your 4jaw does not go back on spot on then not much point.

You also need to get a consistant hand feed on the topslide as you can see by the blue there are steps in the taper.

Are you sure you will be able to improve the existing runout, something like this is best done with a toolpost grinder that can take fractional amounts off. You will also have to get the extension back in the same spot each time you mount it

Jason

Edit just a thought why not put a taper to take an ER collet in the end and thread for a nut , rather than an MT taper.
« Last Edit: April 02, 2010, 04:30:32 AM by Jasonb »

Offline AdeV

  • Madmodder Committee
  • Hero Member
  • *****
  • Posts: 2229
  • Country: gb
Re: Edgwick spindle taper adapter
« Reply #3 on: April 02, 2010, 05:48:57 AM »
Andrew - No, I don't know what the taper is (nor does t'Internet, it seems). The sleeve I have was made for a Mk1 Edgwick, but doesn't appear to be original equipment, i.e. it's not ground to a smooth finish. But it does fit quite well into the taper, it just has that damn runout.

Jason - yep, I had the DTI right on the centre height, albeit measured with a dead centre in the tailstock which - as Ralph pointed out when he visited - might not be 100% spot on.

I've not checked to see how well the 4J repositions itself when re-mounted. It seems to go back straight enough, and there's an "A" stamped on the spindle which allows me to put the same bolt of the chuck through the same hole each time. I'll maybe try it, if my back is up to manoeuvring that lump for any length of time.

As for the steps in the taper - if you mean the ones near the very end, they are deliberate. I cut the taper a smidgeon too long, and had to make a piece which goes into the main spindle bore. The step near the top of the taper (where there's a thin line of blue) is a genuine accidental step, which needs resolving... I don't have a toolpost grinder, unfortunately, so I'm stuck with turning tools. I may cheat & do what I've seen done on some morse tapers; and cut a recess in the middle, leaving say 1/2" either end to actually mate up to the internal taper; but I need my main taper to be about right first...

Your final thought; it's a good one; but as I say my main desire has been to allow me to run the ER32 chuck without removing the 4J. If I make the end of the sleeve take an ER32 collet, then it'll be inside the 4J jaws, and I'm back to square one.
Cheers!
Ade.
--
Location: Wallasey, Merseyside. A long way from anywhere.
Or: Zhengzhou, China. An even longer way from anywhere...
Skype: adev73

Offline Divided he ad

  • WARNING: LIKES SHINEY THINGS
  • The Collective
  • Hero Member
  • *****
  • Posts: 1946
  • Country: gb
  • Between Chester, Wrexham, ruthin & Holywell :-)
Re: Edgwick spindle taper adapter
« Reply #4 on: April 02, 2010, 07:49:43 AM »
Looks and sounds like your having fun Ade!?  :bang:


You'll get it sooner or later, anyone who's willing to attack that sump is going to get this done  :thumbup: 



Nice to see a return of the  "Plastic Hammer of Destiny"   :lol:







Have fun  :dremel:







Ralph.



I know what I know and need to know more!!!

Offline AdeV

  • Madmodder Committee
  • Hero Member
  • *****
  • Posts: 2229
  • Country: gb
Re: Edgwick spindle taper adapter
« Reply #5 on: April 02, 2010, 11:20:36 AM »
Wow, this is proving to be a nightmare... Dunno about "fun" Ralph, guess I need  a lot more practice on the lathe yet...

...having cut, filed, re-cut, re-filed the taper umpteen times, and still getting absolutely nowhere near even close to a fit, I've decided to try plan "B"...

The major hassle is taking the chuck off each time to check the fit. It takes lots of time, and is ultimately disappointing... so plan "B" is to make a copy of the Edgwick spindle taper in aluminium (and I can use the original sleeve to check the fit, fettling it until it's just right. Once I'm happy with the inner taper, I can re-chuck the steel, and use the aluminium piece to check whether i'm on target with the taper or not. When THAT's done, I can finally remove the chuck & stand a fair chance of having the new taper actually fit...

What a palaver.
Cheers!
Ade.
--
Location: Wallasey, Merseyside. A long way from anywhere.
Or: Zhengzhou, China. An even longer way from anywhere...
Skype: adev73

Offline sbwhart

  • Global Moderator
  • Hero Member
  • *****
  • Posts: 3522
  • Country: gb
  • Smile, Be Happy, Have Fun and Rock Until you Drop
Re: Edgwick spindle taper adapter
« Reply #6 on: April 02, 2010, 12:25:52 PM »
Hi Ade

There may be something not quite lined up or lose in the set up,  Bearing nackered compound not following a true line etc, this could be why your having problems hitting the mark, have you thought aqbout trying another method are usualy turn morse tapers between centeres by off setting the tail stop.

The set up is similar to this, it takes some of the oportunity for error out of the set up.







Hope this helps

Stew
A little bit of clearance never got in the road
 :wave:

Location:- Crewe Cheshire

Offline Dean W

  • Hero Member
  • *****
  • Posts: 571
  • My kingdom for a lathe!
    • Projects web pages
Re: Edgwick spindle taper adapter
« Reply #7 on: April 08, 2010, 11:24:14 PM »
How are you coming along, Ade? 

Dean
Dean W.

Shop Projects:
http://www.deansphotographica.com/machining/projects/projects.html

Praise the Lord and pass the Carbide!

Offline AdeV

  • Madmodder Committee
  • Hero Member
  • *****
  • Posts: 2229
  • Country: gb
Re: Edgwick spindle taper adapter
« Reply #8 on: April 09, 2010, 07:02:43 PM »
I've not had much time in the shed of late, the taper in the aluminium is partially cut, but other than that I'm no further forward...

Hope to progress on the sump this weekend, but I'm going to put the spindle off until after I'm finished with that one.
Cheers!
Ade.
--
Location: Wallasey, Merseyside. A long way from anywhere.
Or: Zhengzhou, China. An even longer way from anywhere...
Skype: adev73

Offline AdeV

  • Madmodder Committee
  • Hero Member
  • *****
  • Posts: 2229
  • Country: gb
Re: Edgwick spindle taper adapter
« Reply #9 on: July 19, 2010, 04:44:35 PM »
Right. As the glue is still curing on the sump, I figured I'd work on something else tonight. And what better than this damn spindle sleeve, which is what drove me nuts a couple of months ago... It was all still sitting there in the lathe, so I figured what the heck, let's crack on.

As per my last couple of posts, I've been making a "female" version of the spindle taper; the idea is, I can trial-fit the original spindle sleeve until it fits; then when I cut the steel piece, I can use the aluminium version to check the fit of that. However, having had a few months off, and having had no luck getting the taper to fit right, I decided to go back to step 1. That's where today's little adventure starts...



The first job was to re-measure that taper. I had a bit of a brainwave  :smart: (at least, -I- think it's a brainwave). Wheras before I'd used calipers & measured in 2 places, this time I used the mill. Should be much more accurate. Here's the setup:





The original taper is clamped lightly to the mill bed. The dial indicator is setup to deflect as it bumps into the side of the taper. I used the "Y" axis to get it bang on the centre line (i.e. the point where deflection was at its maximum - see 2nd pic above). Having established this, I then backed away, and came back in, zeroing the dial. Once the dial read zero, reset the X-axis DRO to zero, and back away in the X axis.

Now raise the table by 1" (effectively lowering the DTI by 1"); and finally move the X axis back in to the taper. When zero is indicated, the taper-per-inch can be read directly off the DRO. It was 0.025":



Just for good measure, I repeated at 2" and 2.4" (that being almost the entire taper length), getting readings of 0.0495" and 0.0585" respectively.

Next, a bit of triggery-pokery (you know, I've not used this much maths since I was in school....), gave me an angle of approximately 1.4o

Just before I go any further, I'd like to point out something that you, dear reader, as well as I both missed: Back in my very first post, I measured the taper-per-foot at 0.605". In fact, as you've probably guessed by the description above, I actually measured the taper-per-inch (reading 50.4thou - not bad for hand-held calipers). What I failed to do was divide the result by two!
:doh:

The actual Taper is 0.300"/ft - my machinery's handbook is not handy right now, so I don't know if that's a standard taper or not.

Anyway, back at t'lathe, I reset the cross-slide to 1.4o as near as I could eyeball it, and re-cut the taper at the new angle. Then, the moment of truth: I blued up the original spindle adapter, and gently whacked it into the aluminium piece:



And there it is! It fits! It doesn't wobble about like a wobbly thing! It was actually quite an effort to get it back out again, it stuck that well, and here's where the blue has gone:




Now..... I realise the surface finish in there is a little sub-optimal (let's face it, it's sh*t) - that's because the boring bar chattered like mad. I'm not desperately worried, because the 3 lines of blue show it's basically the correct angle. All I'm interested in is that it grips top & bottom of the taper; I don't care about the middle (well, not much anyway). I've not taken it off the lathe yet, though; can anyone give me any hints on how to reduce chatter in the boring bar? If so, I will have a couple more goes at getting a better finish.

I was cutting at 430rpm, using an HSS tool, which seems quite chunky; but it vibrated like mad. It sang even more at 630rpm (the maximum my lathe will do), and about the same at 290. I didn't fancy going lower because I'm sure slower != better in this case. DOC varied, that last cut is about 0.005". But it chattered like mad at any DOC from 0.030" (the deepest I dared take) down to 0.001".

I'll probably be back on the sump tomorrow, but I'm MUCH happier now I know what I did wrong before. And especially now that the taper fits properly.      :headbang:
Cheers!
Ade.
--
Location: Wallasey, Merseyside. A long way from anywhere.
Or: Zhengzhou, China. An even longer way from anywhere...
Skype: adev73

Offline Divided he ad

  • WARNING: LIKES SHINEY THINGS
  • The Collective
  • Hero Member
  • *****
  • Posts: 1946
  • Country: gb
  • Between Chester, Wrexham, ruthin & Holywell :-)
Re: Edgwick spindle taper adapter
« Reply #10 on: July 21, 2010, 07:45:10 PM »
Ok Ade.... So I got to the bit where the taper fits and I'm sure all that maths stuff worked right  :smart:  Just don't ask me to recite it !!  :scratch:   :lol:


Such a way with words...
Quote
I realise the surface finish in there is a little sub-optimal (let's face it, it's sh*t)
:lol: 


I like that  one  :thumbup: 



Glad you got it done.... Now what was you going to do with it again?   ::)




Ralph.




I know what I know and need to know more!!!

Offline AdeV

  • Madmodder Committee
  • Hero Member
  • *****
  • Posts: 2229
  • Country: gb
Re: Edgwick spindle taper adapter
« Reply #11 on: July 21, 2010, 11:04:45 PM »
Work seems to have interrupted play for a couple of days. I'm just back from a job in Milton Keynes, fooking nakkered I am. I hope to to a bit tonight, but I may be too tired to safely use a machine, we shall see...
Cheers!
Ade.
--
Location: Wallasey, Merseyside. A long way from anywhere.
Or: Zhengzhou, China. An even longer way from anywhere...
Skype: adev73