Thread: Another Arbor To Turn - Suggestions Welcome.

Hi BT,

Build it up with weld and re-machine it sorry couldn't resist

Simplest solution would be to solve the problem of how to dissassemble it.

I see they offer a Schaublin arbor on page 403...

Ray

Hi BT,

Would you consider making it in two parts? 1. taper adaptor 2. Drawbar adaptor/nut for holding taper adaptor on.

Stuart

Hi Bob,
I like Stuarts suggestion, otherwise i would go with 2 or 3. If you wanted to go with no. 2 i have an M16x2 tap i could lend you so you don't need to worry about the thread.

I take it the STP only drives on the taper (and the fact the thread is pulling it into the taper) and cannot be uses safely in reverse?

Ew

Originally Posted by RayG

Hi BT,

Build it up with weld and re-machine it sorry couldn't resist

Simplest solution would be to solve the problem of how to dissassemble it.

I see they offer a Schaublin arbor on page 403...

Ray

It's a shame Ray but I don't have page 403 . This page shows a 30 taper mounted.

KaiserPiccolop3_zps20780286.jpg

Originally Posted by Stustoys

Hi BT,

Would you consider making it in two parts? 1. taper adaptor 2. Drawbar adaptor/nut for holding taper adaptor on.

Stuart

Has merit Stu. A lower double tapered sleeve held snugly in place with a M 16 nut / M12 draw bar threaded combo.

Originally Posted by Ueee

Hi Bob,

I like Stuarts suggestion, otherwise i would go with 2 or 3. If you wanted to go with no. 2 i have an M16x2 tap i could lend you so you don't need to worry about the thread.

I take it the STP only drives on the taper (and the fact the thread is pulling it into the taper) and cannot be uses safely in reverse?

Ew

Non reversible Ew.

I have a box fresh set of Goliath M16 taps I purchased for the side lined table lowering plate project. Might get to use them after all. I would cut the thread on the lathe and probably only use a tap for clean up.

Thank you Ray, Stu and Ewan for the suggestions.

Bob.

You can dream about stuff till the cows come home but pen and paper tell how it is or could be. I'm weaning myself off the two piece idea because I can't see how it could be achieved.

The sketch shows the STP taper and the wall thicknesses when there is 11mm from the face of the 30 taper's flange to the commencement of the taper.

Now I'm dreaming about how the hell I'm going to machine the thing and maintain concentricity.

BobSC36014010908210.jpg

First if it makes you feel any better, the way I'm seeing it, concentricity doesnt matter a stuff. But you do need to be parrallel.

I'm was thinking the nut/adaptor joint at the line below the M16(though I guss you are worried about loosing so much taper? My theory is that there would be more surface there than on the STP taper).

But binning that idea, now about turning the 30 taper. Turn up a stepped disk, mount in the chuck with the step against the front of the jaws, face, bore to suit the parrallel section at the flange end of the 30 taper. fit the adaptor with a draw bar. The flange will be square to the taper so that and the bore should hold things where they need to be??(you would need to watch the corner radius). Now depending on how good your boring is you could have a little run out(though with you I doubt it will be much :P) but you should be dead on square which is all that matters for a boring/facing head right?

Stuart

So Stu, jump in if I have this wrong.

The chuck mounted ring has a bore of 31.75 mm to match that of the short shoulder on the 30 arbor. The arbor is inserted and held in place with an appropriate drawbar through the spindle. Then the STP taper and straight bores are bored leaving me with the challenge of the M16 thread.

Now, that thread is something I wouldn't mind dealing with earlier while the arbor is still a length of 50mm diameter bar. Something I can hold securely. I could be a pussy and bore a tapping hole and a snuggish clearance hole for the tap and tap the bastard in my bench vice with a suitably long tap handle ( I've got one ). Single point threading inside a hole where the action can't be observed makes me a bit nervous. Probably a piece of for others though.

BT

I did a Jarno (external) to MT2 internal some time back and was worried about concentricity too.
The way I got around the issue was to first cut/ bore the internal MT2 in a lump of material. No great precision required as the taper just has to be good. Then I chucked up a piece of bar stock and cut an external MT2. Leaving the external MT2 in the chuck I could then use it as a locator for the blank with the internal MT2 and cut the Jarno taper on the outside. Because the MT2 was concentric with the lathe axis so was the Jarno. I measured and it certainly looked concentric to me, although a few bodies on HSM declared that tapers had to be ground so therefore by definition I couldn't have got it anywhere near concentric.

In your case the angle is steeper so easier to get to and because the adaptor has a through hole you could use a bolt or screw to clamp everything up together.

Michael

Ok, another thought....
Chuck your 50mm bar, drill and tap the M16, and bore all the way through to 10.3 for your M12 (with a boring bar so it is concentric). Bore the STP taper, machine the outside of the bar so you have something to clock off. Mount the baring head with a blank boring bar in a central hole. Hold the blank bar in the 4 jaw and center the stock using that machined outer surface. You should now be able to put the live center in the concentrically bored 10.3mm hole (a bit of a no no maybe as it has not got a 60 deg V) You should then be able to turn the outer of the NT30, finally tap the M12 once off the lathe.

Honestly though, i'd rather turn the NT30 first, and do the rest on the mill with the lathe compound. That way it really cannot be out.

Ew

Edit, basically what Michael said above whilst i was typing-only without using the boring head. More messing about but probably more accurate. The same method is mentioned in a book Mike sent me, in regards to making new spindles for machines. You could even go one step further and make the mandrel double ended, an MT3 on one end to go into the lathe spindle and the STP on the other. A witness mark on the mandrel and spindle and you should be able to use it again if the need arises.

If I understand correctly Ewan, where you and I differ in approach is that I'd be making up a dummy STP taper and using that where as your suggestion is to use the boring head as the (dummy) STP taper?
Yes, well it looked like we were cross typing.

Theoretically that might work but you'd have to get the boring head dialed in exactly which I think could be harder than it seems. As the boring head is made to move, I'd also be nervous that it would shift on me during machining, spoiling the set up.

Another option is to make up a female form 30 taper. If the surface at the small end is square to the form axis and there is a surface externally to allow centring in a 4 jaw, that might give you something to hold a pre-machined 30 taper blank in, but again would depend on how accurately you managed to position the 30 form.

Michael

Ok. More pussyism.

I buy an 30 arbor from CTC for a bit under 40 bucks landed, I bore a clearance hole and tapping hole for the M16 with the arbor in the 13's spindle. Hand tap in the vice then bore the straight and tapered STP bores back in the mill.

Setting the STP taper angle could be achieved along the lines of Ewan's suggestion. A pretend boring bar in the head and installed in a collet or whatever in the mill's spindle and the compound zeroed off the STP.

I know that absolute concentricity is not as essential as squareness but a way of ensuring that the pretend boring bar was concentric to the mill spindle would be turning down a length of half inch bar ( held in my Brown and Sharpe side lock 30 chuck) to 12mm, the boring bar size the Kaiser accommodates. One variable removed.

BT

ps. I intend sending a message to Kaiser in Rümlang seeking advice about the head and I'll ask them about an arbor. I fear the price.

Will you be able to tap the CTC arbor Bob? There is no way i would try tapping the arbors i have from Taiwan tools (Ann way branded).

Ew

Hi Bob,

Yeap thats it.

As far as the M16 goes I'm currently tackle that before the taper either you can single point it all the way(at least you can see the start), single point it in reverse or just tap it, if you're worried about the tap making arbor or ring slipping, you could put flats on the ring and use a four jaw with a pin in the ring in one of the drive dog slots.

Then bore the taper(I cant think of an easy way to check the taper depth without the thread being there first) Hoping that you can pick up the thread easy enough after boring........shouldnt be to hard with a M16 thread right?

If you really want to tap first. How about.
Turn to dia(with enough overhang to get the mill in for the dog slits), face, bore tap diameter to the STP taper depth, bore tapping diamater to the thread depth. Mill drive dog slots. Tap in the vice. Turn up a mandral tap diameter(if the mandral is out of 50 bar you'll have a nice big shoulder to pull up on so you might be able to turn the the 30 taper without a center and be able to remove it for a test fit and have it go back "pretty close". Then continue as above.

Stuart

p.s. wow I type slow lol

Originally Posted by Ueee

Will you be able to tap the CTC arbor Bob? There is no way i would try tapping the arbors i have from Taiwan tools (Ann way branded).

Ew

I'm nervous about it Ew.

I have modified two of their arbors. The first one required some external thread cutting to suit the mounting of my little Craley boring head. But it was a fine thread, not a 2mm pitch. The other modification was when I bored the guts out of the second arbor to suit the Taster's 20mm shank.

Bob.

ps. Ew , how about a photo or three of one of your Ann Way arbors? I came close to buying a saw arbor from Taiwan Tools a couple of years back after Richard " Eskimo" had been promoting their wares but back then they wanted payment via an international bank transfer. Too hard.