RWD3M
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Hi Dave,
I totally get the second bit.
Not sure about the first bit though.
The back plate I have:
View attachment 236481 View attachment 236482
...apart from being manky (I will be cleaning it!) was held on to chuck with 3 x 1/4 BSF bolts and was just spun onto the Lathe Spindle by a great big thread. So I don't know what you mean about D1-x Camloc.... (sorry).
I have just read this post and am still confused, are you saying the chuck as a whole wobbles or is it more the jaws are bell mouthed and need dressing? I do apologise if I am being more stupid than normal.
Ha ha, no need to apologise.
The jaws on my chuck are indeed bell mouthed and I started off looking for new jaws. This then drifted towards replacing the chuck when I saw the price of new jaws!
I don't have much of a budget as work has completely dried up since the epidemic kicked off.
There was talk of 'dressing' on an earlier thread but I'm don't know how to do this or have the equipment. Is it a thing then?
Think he needs to sort the gearbox on that lathe out before he worries about that chuckIt is indeed a thing - die grinder or alike mounted to the toolpost, chuck jaws clamped against something to load them as if you're holding a workpiece, chuck turning slowish and a few passes with the grinder - seefor one of many vijos!
If the jaws are horrbly worn you might have to regrind the bevels so they'll meet to grip small parts, but doable?
Dave H. (the other one)
Think he needs to sort the gearbox on that lathe out before he worries about that chuck
Haven't heard of these guys so had a look on their website. Unfortunately nothing listed at the moment. May give them a ring tomoorrow.Home and Workshop sell new old stock jaws, I got a set of outside jaws for a 5" Pratt chuck for £60.
OK, I have just had to fettle my jaws on my 3 jaw chuck, I was going to grind them like most people do, then I saw a video on youtube, and thought I would give it a go, it worked a treat and would recommend anybody give it a try before grinding. You will need a ceramic tipped cutting tool, mine is only 12mm, I tried 5thou, then 3thou, to clean it up and to finnish I took 1thou. 1000rpm+ and a slow feed.
Solid rock is also on Keith Ruckers channel doing the same process. Good luck if you give it a go, nothing to lose in my eyes, and no grinding dust afterwards to clean up!
...I don't have this boring bar that he speaks of...
I would always advise to someone to think carefully before grinding their chuck jaws. Jaws are unlikely to wear much or quickly, being hardened steel, unless parts have been spun in the chuck many times or the jaws been subjected to several tool strikes. The chuck itself is far more likely to have suffered wear or deformation.
Take a close look at the jaws. Any steps in the sides? Any ridges in the guide slots? No? then they are not worn. You're not likely to bend them either in fact it's just about impossible.
I once bought a chuck that had horribly bell-mouthed 'jaws' but when I put those jaws into an identical chuck they fitted nice and firmly and had almost no runout (as in less than you'd expect from your average 3-jaw chuck). The chuck face was the source of the problem and grinding would have left me with a ruined chuck and two sets of ruined jaws too.
Grinding might serve well as a get-you-by, but it's more of a kludge than a remedy.
In this case, I think I can live with thatIf the front of the chuck has been strained so that it's slightly convex, or the slots have worn, then all that you've done is to correct the fault by altering something else.
The boring bar is not really important. If you have a boring bar that takes inserts, a suitable insert can be found.
It is the type and grade of insert that is the thing to take away from the video.
You need CBN to deal with the hardness and you need a grade of CBN that will handle interrupted cuts.
An eBay via China generic CBN insert may not work as its grade will be unknown. It is better to buy a brand name insert as you then have access to the manufacturer's data which will tell you which grade you need.