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Internal Bore and Taper Grinding - T&C Grinder?

zipfactor

Cast Iron
Joined
Oct 10, 2013
Location
USA - OH
I'm not able to locate a collet nose (collet nut) for the Tree 2UVR I've recently picked up, so I am setting out to make one. With this part being hardened, I'll need to grind the bore and the internal taper to be able to make the part fit correctly according to the print (attached).

I currently do not have equipment capable of internal cylindrical grinding and am not interested in using a tool post grinder on the lathe. My question is would a tool and cutter grinder be a good choice to handle this part? I've been considering buying one for a few other projects coming up and was curious if this would be a good tool for this work.

I'm assuming the grinder would need to have a motorized work holding head to rotate the part with respect to the spindle. Any other considerations?

ColletNut.jpg
 

Cyclotronguy

Stainless
Joined
Sep 21, 2005
Location
Northern California
With the usual suspects the SFM of the grinding spindle is going to be too low to swing a small stone at an optimal speed. That said Sopko makes wheel chucks to collet adapters for several of the common grinder spindle tapers, Allowing for mounted stones to be used: but unless you can get the RPM up or have an aux ID spindle on your T&C, It's not ideal.

Quite honestly an appropriate tool post grinding quill on the lathe and the compound set with a sine bar to your required angle is likley just as rigid a set up. You might even be able to grind the threads while your at it

Remember when you Heat and quench that nut, it's going to come out a bit oversize, make allowances. Or simply make a few out of prehard: Keep them clean and lubed and they will last a long time.
 
I currently do not have equipment capable of internal cylindrical grinding and am not interested in using a tool post grinder on the lathe.

Yeah, me neither. Though i sometimes use a diegrinder mounted to the slide on one of the second op lathes.

My question is would a tool and cutter grinder be a good choice to handle this part? I've been considering buying one for a few other projects coming up and was curious if this would be a good tool for this work.

Yes.
They are extremely versatile, for the shop that can't have "one of each" grinding machines including a dedicated cylindrical.

I'm assuming the grinder would need to have a motorized work holding head to rotate the part with respect to the spindle. Any other considerations?

2 ways to handle it.
Most good T & C's had a speeder accessory for internal work.
They can be more or less difficult to acquire these days, though.

*Cincinnati's looks like this, IIRC (not in shop at moment) it's good for 25,000 rpm on high machine speed. :

smt_SCM_bb4.jpg


Belted speeders were also made OEM, and aftermarket, for surface grinders. Tough to use on a surface grinder, though, due to limited table space and Z (in/out) table travel. They were more for slots on surface ground parts and such.

Despite the shape of this bob, it is canted so that only the front edge cuts. I dress the entire end off as necessary. Internal grinding is quite a slow process. This also brings up the limitations of a T & C for the app: The infeed dials are seldom finer than 1/2 thou, often only .001" Where as a cylindrical dial and screws would be 1/10 that, both in resolution and actuation. Nonetheless, the work can be done on a T & C. Perhaps keeptrack with a DI or DTI of sufficient resolution when it matters. Whith a bob about the size shown, a typical infeed is going to be a couple tenths. Not more than 1/2 thou.

smt_SCM_bb5.jpg


If you can't find a speeder with all the accessories, collets, spindles, etc, an alternative it to make a bracket to mount a die grinder to the wheel head. Most, like Cincy, have multiple pads and area with T-slots to effectively mount substantial brackets, fingers, the speeder, etc, etc. Just make a mount and put the die-grinder where it will be effective to use with the table travels and column rise/fall.

If you do interesting work with hardened steel, you'll wonder how you got along without it.

Good luck!
smt

*OOPs - i was addressing the rpm considerations for the wheelhead, not the work head.

Re: the work head, try to get the original with the T & C. & any other accessories, rests, fingers, wheel arbors, etc, etc. But if you have nothing to start with, i often use an "accurized" import 5c spindex for simple stuff, as your collet nose would be, really. What you have to fix with the imports is mostly the camming action as they rotate. & make sure the spindle is parallel to the bottom and one reference edge. Then keep your eye out for a "real" OEM tilting workhead.
 








 
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