I would thread a stub the same as your spindle using one of the spindle nuts as a test thread so you would have something to 'try' your thread on the spider without removing it from your chuck. Shouldn't be too bad to make. I would also be more inclined to machine it to the first drawing as it offers more support for your spider bolts...maybe even add a 45 degree chamfer to the inside shoulder so you could thread it on snug and it would self center before tightening your set screws.
Well after I got my 4 year old and 9 month old to bed I continued with my project. The lathe I have in my garage is not professional, its just G0602 benchtop from Grizzly, so according to their manual "Note: Since this lathe has an inch leadscrew, do not use the thread dial when cutting metric threads. Instead you must leave the half nut engaged from the beginning until the threading operation is complete." So when threading I have to stop the spindle, back the croslide, then engage reverse, then stop spindle, backup croslide, then move compound and engage forward. So when I press stop, spindle will rotate and since lead screw is engaged, carriage will move and on 1.5 metric thread I get about .150 - .200 until it completely stops. Yeah I hate it, but I can't buy another lathe at this point
Anyway, I got half way through, I decided to go with the original drawing, good thing threading is done and its perfect tight fit. I still have to cut it to size and tap them holes, but it shouldn't be complicated.
While you are set up to cut Metric threads I would cut one more coupling and install a handle on it
to turn the spindle.
A friend on this site did this and I liked the idea of having total control of the spindle and not worrying about the
coasting down of the spindle. If your lathe is in a tight space, a 1/2'' drive ratchet will work well and can be reversed
I also made a threaded nut with 1 1/16 x 16 tpi inside to screw a short threaded barrel in and install the extension nut
in the spindle to hold the back of the barrel. It works well and uses the shoulder of the spindle and the receiver for the
It is a little more work but it gives you total control when you can,t disengage the half nut.
I can call mechanism to engage lead-screw or lead screw engager something... About the lathe its 10x22 and it missing some features I would like to have. Let see if you ever worked with Hardinge toolroom lathe, when threading once lead screw engaged it stays that way, but it has a break and special lever on crosslide to get in and out of thread, love that feature... Of course Hardinge toolroom lathe no longer made, but there are many replicas still build today and they still cost 20 times more then grizzly
Here's one made by EISEN
And the one from Grizzly
Swing over bed: 9-5/8" Swing over cross slide: 6-1/8" Distance between centers: 22" Spindle bore: 1" Spindle thread: 1-3/4" x 8 TPI Spindle taper: MT #4 Motor: 1 HP, 110V, single-phase Number of speeds: 6 Range of speeds: 150, 300, 560, 720, 1200, 2400 RPM Leadscrew: 3/4"–12 TPI Compound travel: 3-1/2" Cross slide travel: 6-1/2" Carriage travel: 18-1/2" Maximum tool size: 1/2" Tailstock barrel travel: 2-1/2" Tailstock barrel taper: MT #3
5" 3-Jaw chuck with two sets of jaws 6-1/2" 4-Jaw chuck with reversible jaws 8" Faceplate Steady rest with 1/4"–2" capacity Follow rest with 1/4"–2" capacity MT #3 dead center 4-Way tool post Chip tray and backsplash Hardened & ground V-way bed
Oil-bath gearbox Tool box with service tools Number of longitudinal feeds: 9 Range of longitudinal feeds: 0.0023–0.013 IPR Number of inch threads: 33 Range of inch threads: 8–72 TPI Number of metric threads: 26 Range of metric threads: 0.25–3.5mm Overall dimensions: 46" L x 22" W x 16-5/8" H
Last edited by Jinx-); 07-27-2013 at 03:24 PM.
I've just always known, what you call a half nut, as a split nut. I've not had the pleasure of the Harding machines. But I've experienced Clausings, South Bends, Warner & Swaseys, Brown & Sharpe single spindle automatics, Acme-Gridley multiple spindle automatics, New Britain multile spindle automatics, Summit engine lathes (you can dis-engage the split nut on those when metric threading), Monarchs, Lymans, Sydneys and now HAAS. Thats just turning machines, the list is about as long for the mills I have set-up and operated. Punch presses,,, yes, for the part punched and for broaching, precision grinders, no centerless or bore, but pleanty of surface and tool & cutter grinders (making & sharpening). Heat treating,,,,, only on a one one one basis in the tool room. True "job shops" will show you alot in 35+ years. Never a boring moment,,,,,, unless it's with a 'bar'!
"Shoots real good!": definition; it didn't blow-up in my face. 1993 graduate Montgomery Community College 2yr. gunsmithing program