New Vevor 6 Jaw

[Susquatch]

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Peter, what you sketched is more or less what I have. The shoulder in the longer hole is slightly higher than the shorter one. The two holes in the bottom jaw appear to be identical. I tried a 25mm screw in the shorter hole and it fits fine bottoming out on the shoulder not the bottom of the hole. That makes sense because the difference in the shoulder height measures 4.9mm. That tells me that I can clean up the female threads with a bottoming tap and then use 30mm and 25mm screws to hold the jaws together.

I might also make tension buttons with longer screws like I use on my 3 jaw.



It is basically a set of sleeves that spac up the screw head so they can be used as expansion jaws when the jaws are set for OD clamping on a delicate part.

Some day, I'd also like to grind pillars to put on those 6 inside screws to act as chuck stops for squaring up stock held away from the chuck face. The screws are screaming at me to be used that way.

 

[Susquatch]

Robin Renzetti has an excellent video on this chuck aspect where he retrofits.

I think I posted that video earlier in this thread. Might have been a different thread though.

If you tested runout at a different diameter or a different temperature or a different clamping force, big changes can and do happen.

I wasn't really expecting miracles from SetTru anyway. It was just a musing based on the assumption that Vevor's runout was virtually guaranteed to suck. But this thing actually looks pretty darn good, so I'm gunna see what the chuck does without it first.

 

[Susquatch]

Backplate came. It is cast steel instead of cast iron. I'm ok with that but am wondering if this a really a good use of such a nice backplate. Need to clean the surface before cutting, but looks good so far. Hope the 4 pre-drilled mounting screw holes don't get in the way. Easy to check. But didn't do it yet.

 

[Susquatch]

I decided against using the cast steel backplate. I have a regular cast iron back plate that is thicker than a normal backplate. Since the cast steel is also thick, I decided to use the thick cast iron instead. It is all machined and ready to drill for the backplate screws.


Here it is with test fit with the chuck. Won't go on by hand but will with the screws pulling it in.



The chuck only has 3 screws in it. I will change that to 6. For now, it's time to spend time with my grandsons who are here for a long weekend.

 

[Susquatch]

For anyone who is interested, here is a visual comparison between the D1-4 and the D1-5 backplates. (4 on the left)

 

[Susquatch]

Another photo, turned to a tight fit. Just needs screw holes.



I will put a very small mark on it to indicate original indexing, but I will wait till I have the chuck mounted so I can dial it in by rotating the indexing before punching in the permanent index mark.

I'd guess where it is now will be best because the plate was turned at this location. But that assumes the chuck itself was built on its own center perfectly. While that might be true, it isn't guaranteed. Therefore, it is good to have a little wiggle room just in case. One way to get that wiggle room is to rotate the backplate on its own center. Quite frankly, I don't expect it to matter on my lathe because it's runout is so low as is, but I want to try it.

 

[Dan Dubeau]

Looking good. Might have to add one of these to my wish list. Still need to mount that 5c chuck I bought a while back first though....

 

[MrWhoopee]

I received my chuck on Monday and the Shars backing plate yesterday. I disassembled the chuck and was pleased to find that the inside was pretty clean, though the oil was dirty. It did require a lot of deburring. I had to re-cut the threads on the backing plate, they were tapered and tight. Being an optimist, I fitted the chuck to the backing plate with .001" clearance, leaving no room for adjustment. After mounting the backing plate, I put the chuck on the lathe, chucked a 1" dowel pin and put an indicator on it. It read .0025" both close to the chuck and 2.5" away. With a bit more care in the chucking I was able to get under .002". All of this was relying on the accuracy of the factory work. I'm impressed and happy.

 

[Susquatch]

Small setback. Much as I love my Gerardi Vise, it let me down today. I wanted to drill holes in the backplate for the attachment screws. But the chuck won't fit my vise jaws. I'm going to have to mount it directly on the table. I can use some regular t-nuts in the slots and two long 1/2-13 threaded rods from my clamping set. Just need to make sure they don't bottom out and that there is a columnar load at the bolts.

Not happy about that, but there is no such thing as a tool without limits.

My plan is to use the three existing chuck mounting holes and also make 3 more halfway between each of them. Why? Well, why not? My DRO will easily handle the job.

 

[Susquatch]

Mounted the backplate on my mill table next to my vise - easy peasy. But the job is on hold again. I need to order an end mill that can be used to cut the countersink for an 8mm SHCS. My existing endmills are either too big or too small and my countersinks are all imperial.

Hurry up and wait. Crap.

 

[Mike R]

Easy peasy - just replace the easily ordered end mill with a complicated cnc machine like I did that can circularly interpolate the hole using a smaller end mill.

 

[Susquatch]

Easy peasy - just replace the easily ordered end mill with a complicated cnc machine like I did that can circularly interpolate the hole using a smaller end mill.

Ya, and spend the rest of my life fine tuning it, learning how to use it, fixing it, and being robbed of the joy of putting my good old fashioned manual skills to work. I'll be dead before I got that "circularly interpolated hole" done. If I was in a big hurry, I'd just drill it out (with my new Dormer drill set thanks to @JustaDB) and then manually circularly interpolate the bottom with a smaller endmill...... But I'm not in any hurry. I just ordered a 9/16 endmill that should come tomorrow.

 

[Susquatch]

Easy peasy - just replace the easily ordered end mill with a complicated cnc machine like I did that can circularly interpolate the hole using a smaller end mill.

Well, you got my goat! LMFAO! Just did all the holes faster than you could program your CNC. Drilled them to 9/16, then mounted a 3/8 endmill and traced out the OD manually for a nice flat bottom. Took me all of about 10 minutes to drill and "manually circularly interpolate" all the holes. Easy peasy, no math, no programming, no fancy motors, no ball screws, no fancy setup, no calibrating, and no studying or learning. Just an old fashioned manual milling machine and a little skill on the handles. Easy Peasy.

Bonus 9/16 end mill arriving tomorrow.

 

[MrWhoopee]

There is some variability with successive chuckings, but I really can't complain. Runout seems to be consistently better if the pin is inserted back into the jaws even with the face of the chuck.

 

[Susquatch]

Runout seems to be consistently better if the pin is inserted back into the jaws even with the face of the chuck.

Likely because of more even loading of the jaws?

I would have expected better axial runout, but it actually also improved runout close to the jaws too.

Good observation. Thanks for that.

When I get my backplate installed, I'll try it that way too.

 

[PeterT]

need to order an end mill that can be used to cut the countersink for an 8mm SHCS.

You might want to consider a tool dedicated for that purpose. I use EM's too but these have shorter cutting length with a reduced neck, a true flat bottom & a pilot guide stub & reasonably priced. I am kind of meh on the guide pillar but that's only when I drill to a smaller clearance hole. I have some that are a bit different on the same nominal counterbore size so maybe varying standards? I know my CAD program has different diameters for the same size head & of course fasteners can vary a bit too. Anyway, getting into the weeds here. If they provide a dimensional table you can see what you are getting into. You can buy them coated, uncoated & maybe different shank lengths.

 

[Susquatch]

I am kind of meh on the guide pillar but that's only when I drill to a smaller clearance hole.

I'm not meh on them. I hate them.

Where do you find ones with smaller nominal guides? I'd love that way better than using an end mill but so far no luck finding them.

 

[MrWhoopee]

I'm not meh on them. I hate them.

Where do you find ones with smaller nominal guides? I'd love that way better than using an end mill but so far no luck finding them.

Same for me, I have a set of imperial c'bores, but the pilots are .030 over. No way I'm drilling a clearance hole that big.

 

[PeterT]

Its always been a mystery to me too.
Example the M8 tool indicates an 8.2mm pilot.
This ASME flavor is (9.00-9.22) for Normal. (8.4-8.55) for Close. (10-10.36) for Loose. So the tool pilot would not enlarge any of these bolt holes.
Maybe I've never understood how the pilot is supposed to work. Or the CB tool itself is specific to class fit like you buy it for the fit? Or maybe you pre-drill for the BB tool & then you open it up?
The M3 seems to match the Close pilot size. But I have a USA M3 tool that is slightly larger.
Anyway, my point is you might find it difficult or cheap to get a 9.5 or 11.0 or 17.5mm EM because its generally an odd duck. Depends if you car or not. And of course socket head are different than hex for the same nominal thread.

Metric Clearance Holes and Tolerances per. ASME B18.2.8-1999, R2010

The recommended drill and hole sizes for metric fasteners are tabulated in this table calculator. The minimum recommended hole is the drill size and the maximum recommended hole size is based on standard tolerances.

www.engineersedge.com

 

[PeterT]

Same for me, I have a set of imperial c'bores, but the pilots are .030 over. No way I'm drilling a clearance hole that big.

Were they from an Asian supplier <cough, metric> re-branded for IMP screws?
If so, I hate that more. At best they might be trying to be helpful to the calculator challenged. But other times they are just changing the label to wedge their wares into a market.