Locking chucks for reversing?

[TTIT]

Cool - I think I've finally found something that hasn't been covered in the forum before :o - at least I couldn't find anything in searches :shrug:
I've now had a lathe with reverse for 6 months and REALLY want to start using the feature but the standard Vicmark chuck has no locking device.

Q1. What are the usual methods of locking the chuck on to the spindle?

Q2. If I use a grubscrew to lock it, should it be angled in to bear on the flange of the spindle? Don't much like the idea of going straight onto the thread.

Q3. Is there some other way so I don't have to drill and tap every faceplate etc etc...?

[rsser]

Hi Vern,

I seem to recall reading somewhere (and that's code for FFM (which is code for Frequently Failing Memory)) ... poss. on the Stubby Yahoo group (so it'll be in the archives, if that's where I read it and this itself is not a case of FFM) that you may not need to lock the chuck. Something about thread cut and ramp-down speeds? [Edit, ah yes, ramp-up speeds!]

I'm not sure I'd be game but search the archives if you're a member.

The odd occasion I've reversed for sanding purposes I've just run a couple of wraps of tape between the spindle collar/nut thingy and chuck, and wound up slowly.

Not sure how either of these would work if you were turning and got a dig however.

FWIW, the Jet faceplate I bought from Garry Pye had a couple of grub screws in it that bore straight down on the thread. Think if I were using it often with them tightened hard, fibre or brass washers might be a good investment.

Alternatively, on the handwheel of the Vicmarc 175 I owned there was a removable collar holding it to the spindle. It matched the VM100 chuck and spindle shoulder on the inboard side so I assumed it could be used there for reverse turning. So all you need is to get Vermec to turn you up a matching Stubby spindle nut/collar thingy.

Hope this helps.

Yep, pretty original thread alright. Setting the bar high for the next one ;-}

[Added: on reflection, a grub screw prob wouldn't do much if you got a dig .... just drop your tool and run :) ...]

[TTIT]

........Something about thread cut and ramp-down speeds? [Edit, ah yes, ramp-up speeds!]

I'm not sure I'd be game but search the archives if you're a member.
..................
Not sure how either of these would work if you were turning and got a dig however.Start-up isn't a problem with the long ramp-up set but the first time I tried it I nearly had the whole lot in my lap when I applied a bit of resistance - left the whole thing hanging on by about a 1/2 turn:o I can't access the group from work - will try tonight from home.


..............Alternatively, on the handwheel of the Vicmarc 175 I owned there was a removable collar holding it to the spindle. It matched the VM100 chuck and spindle shoulder on the inboard side so I assumed it could be used there for reverse turning. So all you need is to get Vermec to turn you up a matching Stubby spindle nut/collar thingy.This bit sounds very interesting! Anyone got a pic of what Ern's talking about?


........... [Added: on reflection, a grub screw prob wouldn't do much if you got a dig .... just drop your tool and run :) ...]Tried that - blessed is the knee-high emergency stop rail!!:B:U

[OGYT]

Vern and Ern, I reverse sand, every other grit. When I put the chuck on, I get it snug, then, with the spindle locked, I put the wrench on it, and give it a pretty good bump with the heel of my hand. Never had it come loose, but sanding ain't makin' shavins, and I've been wanting to reverse turn a mite, too.
Last pot pourri bowl I made, I had a place of tearout on the opening flange. The only way I could get it out was to reverse the lathe and take a very light cut with the skew point. (talk about a death grip! :yikes:)
My spindle has a groove around it, behind the threads, for a grub screw. And my Spindle Adapter has a grub screw which I use, but my chuck doesn't.
Here's what I've been thinking about doing: Drill a hole in one of the flats on the chuck insert. Thread it for a grub screw. Install the chuck like I normally do. Put the grub screw in tight enough to mark the thread on the Spindle Adapter. Then take it all apart, and lock the spindle adapter down on my drill press, and drill a small hollow for the grub screw to seat where it marked the thread.
What do you think?

[rsser]

Al, good thinking I reckon.

Would it stop a 50 lb lump of lumber you've just got a woppa dig in? Don't reckon; it'd just shear.

But then maybe it's just a threshold thing ... holding it there under normal circumstances.

Vern, think you've dealt with my FFM ... short answer is clearly no to whatever it was I got from the Stubby Group.

Maybe you didn't have it cinched up tight enough ... maybe you could use breakable Loktite ... maybe etc.

... maybe just ring Vermec.

(Or email Vicmarc asking for a hi-res pic at 45 degrees of the outboard end of a 175 :D )

Maybe if you got the collar thingy off and you can weld you could just put on a few dobs of metal on it to match the collar.

[rsser]

K, just been out to take a dekko.

The nut/collar thingy is part of the spindle ... so much for that idea (at least, that simple idea; still poss'ies there).

The grub screws (on the Jet faceplate) did leave visible bite marks in the last thread closest to the headstock. My VM100 thread doesn't come close to screwing down that far FWIW.

[TTIT]

........ Here's what I've been thinking about doing: Drill a hole in one of the flats on the chuck insert. Thread it for a grub screw. Install the chuck like I normally do. Put the grub screw in tight enough to mark the thread on the Spindle Adapter. Then take it all apart, and lock the spindle adapter down on my drill press, and drill a small hollow for the grub screw to seat where it marked the thread.
What do you think?Good - except that every adaptor you screw on would need to line up with the same hole - and I am buying 2 more chucks next month and already have 3 faceplates, 2 vacuum chucks, screwchuck etc. I think lining it up with the groove would be easier - except mine doesn't have one. :C


Al, good thinking I reckon.

Would it stop a 50 lb lump of lumber you've just got a woppa dig in? Don't reckon; it'd just shear.

But then maybe it's just a threshold thing ... holding it there under normal circumstances..................With a groove on the spindle, the screw wouldn't have to be tight on the spindle, just lowered into the groove so that if the chuck started to unwind, it would stop where the screw hits the side of the groove. The more I think about it, the more I like it - but that still doesn't put a groove in my spindle now does it.:~ How hard do you reckon the Stubby spindle would be against my 3mm parting tool???:no:


....... My VM100 thread doesn't come close to screwing down that far FWIW. Odd :confuzzled: - my VM100 butts right up - I never use a spacer????

[rsser]

Last point first Vern .. sorry, my lack of tech language; fair bit of the headstock end of the insert is not threaded is what I should've said.

So, was it a parting tool that was set to send you running? If so ..

1. how far out from the centre?
2. how hard did you go in?

Not saying you did anything wrong ... just an issue of how much leverage could be applied without insurance.
.

[TTIT]

Last point first Vern .. sorry, my lack of tech language; fair bit of the headstock end of the insert is not threaded is what I should've said.Now I'm with ya! Maybe I could utilise that feature somehow - hmmm.............


So, was it a parting tool that was set to send you running? If so ..

1. how far out from the centre?
2. how hard did you go in?

Not saying you did anything wrong ... just an issue of how much leverage could be applied without insurance.
.My bushtrailian hasn't come across right Ern - what I meant was that I might have to try making a groove like Al's in the Stubby spindle using a parting tool?:o

[Skew ChiDAMN!!]

About grub-screws leaving bite marks... I just drop a small bit of lead shot down the hole before inserting the grub-screw. :thyel: I don't recommend "pointed" grub-screws either; with the lead shot a plain flat-bottomed grub is more than sufficient and does less damage.

Teknatool include small nylon disks with their lathes to do the same thing, which are OK if you're going to use only the one insert, but as I move my chucks between lathes and change the inserts on a regular basis, well... gimme the lead shot every time!

[Manuka Jock]

I drop a pinch of tiny fiber/dust down the grub screw hole with my Teknatool chucks and inserts . The supplied (one only ) wee red fiber dot did not survive the first change over . Nor did the leather dot I used next.
And we all have an inexhaustible supply of fiber/dust eh :)

I have seen brass grub screws recommended , but they are rather hard to find with the big magnet , if dropped :(

cheers ,
Jock

[BernieP]

G'Day Vern

Would you not use a vacuum chuck when reverse finishing, Just a thought:dunno::dunno:

Cheers
Bernie

[Cliff Rogers]

I use grub screws.

The Vicmarc VL300 has a flange on the spindle & back of the chucks & faceplates that a split collar will fit around to hold it but it takes too long & it doesn't work with the other brands.

The grub screw lands on the last thread & doesn't cause much more than a couple of small arcs on the top of the thread.

It is true that you get them in different places for different chucks but I have 8 or 9 chucks & 2 or 3 faceplates & I haven't worn out the thread yet 'cos I only do them up if I need them.

[hughie]

Hmm this a bit of a tricky one. On my modified MC1100 if have a small amount of shaft poking out of the Headstock bearing [5-6mm] then the chuck.adaptor etc starts.
I have considered making a bush/sleeve to fit the shaft with a nice snug fit. Making the sleeve/bush sufficiently long enough to go over my hex headed chuck insert...two different diameters here the shaft is smaller than the hex of the adaptor.

Firmly lock the adaptor to the shaft via grub screws [ 3 places] and possibly dimple the shaft for greater grip.

Drill and tap at least two further holes to lock grub screws onto the flats of the hex. This should then secure the chuck from unscrewing.

:?
well it makes sense to me......:U

[cedar n silky]

Good one Vern. I have been wondering myself! I know my VL175 has a locking ring, and in the manual it shows it as a 2 part ring, and the manual says, " the two part ring will grab half on the spindle and half on the chuck or faceplate. This is ideal for reverse turning or sanding"
Thats all and good, but it still was a bit light on detail why the chuck wont wind off the insert, if you get a dig in, and yes I thought "gee, thats a fair load to put on the grub screw/s that I think from memory butt against the insert. I did ring Vicmarc, (or was it the retailer?) (there's that FFM again)way back, and had a hurried conversation, where I think there was talk of drilling a hole to accomadate the grub screw, but I put that on hold, as I didn't want to drill into any part of the chuck or insert, until I knew for sure!:DPlus it wasn't a priority at the time to sand in reverse ETC!:; I look on in interest, and might follow through with another call to Vicmarc on Friday, unless I find the answer here first.:2tsup:

[TTIT]

....... I just drop a small bit of lead shot down the hole before inserting the grub-screw. .


......I have seen brass grub screws recommended


.........I haven't worn out the thread yet 'cos I only do them up if I need them.


.......and possibly dimple the shaft for greater grip.
All good and valid points and ideas :2tsup:- combining all this lot in one way or another should do the trick. Will report back when done:U No doubt about it - this forum would show those yuppies what 'brainstormin's' all about!:;


Would you not use a vacuum chuck when reverse finishingThose too will be locked with the same method - when I decide which ones to use :confuzzled: