A Go At An Arbor.

**Anorak Bob** · 31st December 2013, 10:33 PM

A while back Michael G showed us the innards of his Haimer Taster in his Lemonade thread and of particular interest to me was the direct mount 30 taper arbor Michael made - https://www.woodworkforums.com/f65/ma...ml#post1680733. Michael subsequently sent me his arbor for a look and fiddle.

I thought I could copy MG's efforts and make a slightly shorter version by reducing the thickness of the arbor's drive flange. In reality I saved nothing due to my version having a longer parallel "gauge line" section between the flange and the taper

. I do have a taper turning attachment but made, in hindsight, a probably poor decision to cut the taper with the compound. To set the compound at the appropriate angle I zeroed a Brown and Sharpe 30 taper endmill holder in my 4 jaw then using a tenth DTI set on the spindle centreline, adjusted the compound to suit.

After I had turned the taper, I could not check its fit until I had cut the drive dog slots in the flange. That necessitated the use of the piddly Hercus dividing head and tailstock due to me not wanting to remove the work from the chuck. The DH and lathe share the same spindle thread. With the flange notched, the blued arbor appeared to be a good fit. I then turned a spigot on the outer end of the arbor enabling it to be held in the 13's dividing head's 3 jaw chuck while I drilled and tapped the arbor's flange for the four M4 set screws used to precisely centre the Hamer. A concern I had was when to bore the 13.75mm wide by 12mm deep recess required to accommodate the Haimer's stumpy spigot. Before I drill and tap the 4 holes and face the challenge of trying to clean up the burst through or after making the four holes. I chose the latter and the small HSS boring bar I used left a nice finish even with the interrupted cuts. If I had used carbide for boring the hole in the 1045 with the holes insitu, I reckon I'd have probably snapped a tip.

I discovered a neat feature on the mill's dividing head when fitted with the worm and worm wheel. With the swing away worm engaging the wheel, the worm wheel's two piece construction allows the gear to be loosened on its hub enabling the spindle to freewheel. Handy because I wanted the four 90 degree spaced holes offset 45 degrees from the centreline of the flange notches. I indicated off the flat of a notch. It was the first time I've used the head set up with the worm, division plate and sector arms.

With the arbor completed I mounted the Taster and centred it via the screws while indicating off its stylus. Great until I removed it from the mill's spindle and reinserted it. After a lot of readjusting the best result I could achieve on reinsertion was around 0.005mm TIR. This was following adjustment of the screws where no run out was evident.

I removed the arbor from the Taster a number of times and attempted to adjust the taper in the lathe with 600 wet and dry wrapped around a flat file. A marginal improvement.
Blueing was the biggest issue when testing the fit. I found that the bearing blue I used when spread thin enough to be relevant, was hardly visible enough to deem whether the fit was improving as a result of my adjustments. Canode proved way to thick. Greq Q described a metho haze as being about the requisite bluing thickness but I struggled enough a simple thin smear.

I ended up giving up with a slight improvement on the TIR of 0.005mm. The spectre of checking and adjusting the Haimer at each use doesn't hold a great deal of appeal but as Variant found out to his cost, assumption is the mother of all xxxx ups, so I'm tempted to spring for a ground arbor from the likes of CTC and start all over again.

Sometimes home made ain't worth the trouble.

I'm wondering how others blue their arbors.

BT

**Ueee** · 1st January 2014, 01:10 AM

Hi Bob,
Happy new Year!

The 13's drive dogs are part of the spindle aren't they? A mark with a whiteboard marker down the taper and a small twist in the spindle taper should be very revealing about what is contacting. The twist is the problem though.....

CTC's are BT or CAT fittings, i bought a few NT40 holders from taiwan tools, they are Ann Way branded and of pretty decent quality. Taiwan Tools:Tooling System/Cutting Tools-Milling Machine Tool Holder,Sidelock End Mill Holder,CNC Tooling system cutting tools,Collet Chuck Boring Bar,Milling Cutter,Lathe turning tool holder
I bored one of mine from 25mm to 1.250", they are bloody hard though, i used a WNMG negative rake insert 16mm dia boring bar. I bolted the BXA toolpost to the mill table but it was not rigid enough, ended up just clamping the boring bar holder down on the table.

Cheers,
Ew

Edit, is pic #10 the original arbor from the taster?

**Michael G** · 1st January 2014, 07:08 AM

A confession to make Bob - The arbor I sent you was not finished. My tooling is all 40 taper, so the 30 was just a trial piece. I had no way of checking the form or (and this could be the problem you have) making sure that the face that the taster sits against is exactly square to the spindle axis. Perhaps clamp a lathe tool to the mill table and take a skim off. See if that helps.

Strangely, I'm not too concerned about having a 100% match on the taper as I'm not sure that the taper has to be in full contact all the way along. I have several Morse taper drills and possibly a 40 taper (too lazy to check at the moment) that have a section at the large diameter and a section near the draw bar end but nothing in the middle. The important thing about the taper is that it has to seat reliably. This particular application is zero force/ torque so really that's it. The top of my spindle where the draw bar head seats has a slight conical shape so if the bottom of the tooling taper seats and the draw bar bolt seats it is likely to seat repeatably.

The other thing to think about is the thickness of the blue. As we discovered at Scrapefest, it's not all that thick. To get a perfect match between a socket and arbor that will blue up 100% means that the forms have to match at a sub micron level. While my TT device is reasonably good, the slides are not straight to that level - the clearance so that they can slide is going to be greater than that to start with. My lathe compound is probably just as bad, if not worse as it has been used more. A special grinder designed with producing tapers in mind is needed if you want to get that full form match without exhausting your luck reserves.

Michael

**Anorak Bob** · 1st January 2014, 10:08 AM

Happy New Year Boys.

Ew, The tenth photo is of the original Haimer 20mm shanked arbor. I have had a couple of goes at machining CTC arbors, my initial attempt at Taster mounting and the modification of a boring head arbor to gain more Z.

https://www.woodworkforums.com/f65/ta...ml#post1660725

https://www.woodworkforums.com/f65/sq...5/#post1403560

The CTC arbor I will probably purchase is one of these - NT 1-1/2" 18TPI Arbor For Boring Head #H54 though I will have a look at Taiwan Tools' offerings.

I did try bluing with an Artline but with next to no rotation of the arbor it was a waste of time.

299 (Medium).JPG

Michael, I ran the

DTI across the face of the arbor after my attempts at adjustment and found a tenth error. I will pop the head off the mill and remove a whisker with the arbor mounted in the horizontal spindle.

303 (Medium).JPG

**Ueee** · 1st January 2014, 10:32 AM

You need to use a whiteboard marker Bob, a permanent marker does not rub of on contact like the WB markers do.

Ew

**Stustoys** · 1st January 2014, 11:54 AM

Hi Bob,

Happy new year.

I started on this post last year

Firstly I made my arbors a little differently. I drilled and taped one end for drawbar thread. Put a bolt in and center drilled it. Rough to the max taper diameter, finish the flange for the dogs. Mill the slots for the dogs. Part off, turn around in the chuck, center drill. Then you can turn between centers driving with the slot for the dog. Within reason you can have as many goes as you like at the taper. Now instead of trying to tweak the taper on the compound you can move the tailstock(or better yet the boring head center in your tailstock)**.

As far as blueing goes, are you just pushing the arbor in by hand? If so I dont think you'll get a good reading. I think of tapers much like gibs(you know, blue it up and whack with a hammer). So what I do is blue with my roller then do up the draw bar*. Then you'll be able to see the difference between parts that are touching under pressure and parts that have just rubbed against each other by accident.

You know 0.005mm is pretty close right?

There is a bolt from the top holding things together? 87 https://www.woodworkforums.com/attach...147-large-.jpg (yeah I'm pretty sure there will be but I cant see it)

Stuart

*I make no claims that this is the correct way of doing things.
**not 100% sure I did this.

**Michael G** · 1st January 2014, 12:09 PM

Originally Posted by Anorak Bob

Michael, I ran the

DTI across the face of the arbor after my attempts at adjustment and found a tenth error. I will pop the head off the mill and remove a whisker with the arbor mounted in the horizontal spindle.

It will be interesting to see what effect that has - given the lever arms involved that 1/10th is probably going to show up as 4 or 5 times that. Hopefully that will fix the problem, although as Stuart says 0.005mm is pretty close...
Remember that the arbor I sent to you is no good to me so keep it, give it away or use it as a fishing sinker. I don't mind.

Originally Posted by Stustoys

As far as blueing goes, are you just pushing the arbor in by hand? If so I dont think you'll get a good reading. I think of tapers much like gibs(you know, blue it up and whack with a hammer). So what I do is blue with my roller then do up the draw bar*. Then you'll be able to see the difference between parts that are touching under pressure and parts that have just rubbed against each other by accident.

There is a bolt from the top holding things together?

I agree that probably sounds a better method than by hand. Never thought about doing it for gibs though. There is a bolt down the guts of the arbor. For anyone else tempted to try their hand at making a 30 taper like this, the tapping drill needs to be slightly oversize so that the head of the SHCS will slide down.

Michael

**Stustoys** · 1st January 2014, 12:17 PM

Hi Michael,
Happy New Year

Originally Posted by Michael G

Never thought about doing it for gibs though.

I should have said, tapered gibs.

Stuart

p.s. I'm not so sure any error on the face will show up as a repeatablity error........... but then I'd hate to say it wont

**Michael G** · 1st January 2014, 12:25 PM

Originally Posted by Stustoys

I'm not so sure any error on the face will show up as a repeatablity error........... but then I'd hate to say it won't

Not sure it will either, but it's about all I can think of and as the original spindle is ground it may be important.

Michael

**Anorak Bob** · 1st January 2014, 01:01 PM

Originally Posted by Stustoys

Hi Michael,
Happy New Year

I should have said, tapered gibs.

Stuart

p.s. I'm not so sure any error on the face will show up as a repeatablity error........... but then I'd hate to say it wont

And Happy New Year to you too Stu.

I have tightened the arbor gently with the drawbar. Having to belt the thing out with a mallet isn't going to do the Taster much good. I can remove it with with a gentle tap.

The arbor is fixed to the Taster by means of an M6 cap screw passing through a 7mm hole in the arbor, both on mine and the factory version.

I will give the end a lick and see if there is any improvement.

The process I used for making the arbor had its faults. I would have been better off not using the Hercus DH. I like the idea of the centre drilled bolt. I do have another option I could pursue. I have a direct fit 30 taper collet in a 12mm size. https://www.woodworkforums.com/f65/sc...ml#post1543592 I could make a 12mm parallel arbor that will fit that collet and the same size collet in the E(R)20 nose of the high speed head's spindle. It would also fit a 3 Morse collet should I ever desire to use it in the little Hercus mill. The downside would be the loss of a few millimetres of Z.

BT

**Stustoys** · 1st January 2014, 01:37 PM

Originally Posted by Anorak Bob

I have tightened the arbor gently with the drawbar. Having to belt the thing out with a mallet isn't going to do the Taster much good. I can remove it with with a gentle tap.

I was just talking about for blueing.

I'm about to run out but two questions

Does anyone have a tolerance spec for these tapers?(I guess it will be in Machinest hand book)

Does anyone have a taper measuring set up? I have a couple of ideas

wasnt I not going to start new projects?

Stuart

**RayG** · 1st January 2014, 01:49 PM

Happy New Year Bob,

The "old school" method would be to use lamp black, just wave it over a candle flame... messy but very effective.

Ray

**Anorak Bob** · 1st January 2014, 02:55 PM

Originally Posted by RayG

Happy New Year Bob,

The "old school" method would be to use lamp black, just wave it over a candle flame... messy but very effective.

Ray

Happy New Year Ray.

Old school is sounding appealing. Can't be any messier than having blue from A to B.

Bob.

**Techo1** · 1st January 2014, 04:01 PM

Originally Posted by Stustoys

I was just talking about for blueing.

I'm about to run out but two questions

Does anyone have a tolerance spec for these tapers?(I guess it will be in Machinest hand book)

Does anyone have a taper measuring set up? I have a couple of ideas

wasnt I not going to start new projects?

Stuart

I always use a sine bar, it's the only way to be sure that you have the tolerance on the angle in the correct direction.

**Anorak Bob** · 3rd January 2014, 10:08 PM

Originally Posted by Michael G

Not sure it will either, but it's about all I can think of and as the original spindle is ground it may be important.

Michael

I reinstalled the arbor in the horizontal spindle removed a whisker from the face. Mounted back on the Taster I have 0.002mm TIR repeatable with the arbor inserted in the same position in the spindle. Reversed 180 degrees, it's about 0.006mm.

I squandered too much time making a 12mm straight arbor. Squandered because there is no accurate repeatability and it uses too much Z.

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