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View Full Version : Trueing chuck jaws, take 2, or a day well spent...



irving2008
30-08-2009, 07:43 PM
As discussed in an earlier thread I needed to true up the jaws on the lathe. Having finally got some time to spare today and the mill is in reasonable shape and my clamping kit had arrived so I could now properly mount the milling vice I thought I'd have a go.

Sadly my camera battery was flat so put it on charge for later... pic is of the three retainers after I'd finished for the day... only one I took in the end.

First task is to make the chuck jaw retainers, so I cut three 1" x 2" pieces of steel from some 1/4" ground stock I had. A new hacksaw blade made short work of that! I really must get a cutoff saw or mitre saw with and abrasive cutting disc.

Next mount the milling vice on the table... first problem, the 1/2" BSW studs wont go through the 12mm holes in the vice base. Whip the base off, invert, clamp down to the table (oh so easy with a proper clamping kit) and mill out the slots to 13mm.

Reassemble vice, bolt down, align with quill, lock it all down.... end to end on vice jaws (or a parallel held in them) - no movement on the DTI!

OK, face mill in, face off the steel pieces one by one, flip them over do the other side. Easy.

Next, cut the slots... hmmm, hacksaw or mill them? Oh, on a roll with the mill, lets try a bit of slotting. First piece, 3mm slotting cutter in MT3 collet, take light cuts, do it in 5 passes... 2nd piece do it in 3 passes...
3rd piece, get too cocky, 2 endmills later its done. Swap over to the drill chuck and drill the holes to give the required springy effect.

Can't wait to get the new 3phase motor for the mill, all this belt changing is a pain.. the VFD is sitting here waiting for a cheap motor to come along on ebay.

Set up the air grinder spindle in the toolpost, it fits rather well. Fit the jaw retainers to the chuck, lock it down, spin up the chuck and the grinder (and the compressor) and 15min of intense noise later one set of shiney chuck jaws...

chuck up a piece of 20mm ground round bar (offcut from a slide rail)... run out at the chuck now down from 0.5mm to 0.03mm (0.0012"), not bad for an 85y old lathe!

BillTodd
30-08-2009, 09:32 PM
Did you inside and outside faces?


all this belt changing is a pain..

Isn't it just !

I've been looking at the possibility of using a Scooter variator (CVT) but the standard 3:1 range doesn't seem enough to be worth while (My Hardinge manages to get 8:1 out of similar sized pulleys so I'm still investigating the idea).

BTW does your machine have a proper 'B' section stepped motor pulley?

Mine is fitted with an 'A' section which is eating the rear belt - I'll have to make a B section step pulley for the motor because they 'don't exist', according to every supplier I've spoken to! - I have some nice new fenner belting waiting to be fitted.

irving2008
30-08-2009, 10:33 PM
Did you inside and outside faces?
No just the inside. I need a 6" jubilee clip to do the outside faces..




BTW does your machine have a proper 'B' section stepped motor pulley?

Mine is fitted with an 'A' section which is eating the rear belt - I'll have to make a B section step pulley for the motor because they 'don't exist', according to every supplier I've spoken to! - I have some nice new fenner belting waiting to be fitted.I have no idea, but I did notice the rear belt is considerably more worn than the front one, but whether that is because the front one is new or the rear one is wearing due to the condition you suggest i dont know. How would I tell if it is A or B section?

All in all I am quite pleased with being able to use the mill in anger... it been sitting there virtually untouched since I bought it last October. My machining skills need more practice but plenty of projects in the offing now... starting with the top- and cross-slide screws on the lathe... but thats another story

BillTodd
30-08-2009, 10:55 PM
How would I tell if it is A or B section?
B section is bigger 0.66" compared to 0.5" - you should be able to tell visually, the Idler and Spindle pulleys will be B section.