I find that this cuts my 4 jaw chuck indicating time to less than half.
https://www.youtube.com/watch?v=fq-Psrtj-uw
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I find that this cuts my 4 jaw chuck indicating time to less than half.
https://www.youtube.com/watch?v=fq-Psrtj-uw
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Thanks mr_modify1! We've added your Chuck Setup Tool to our Measuring and Marking category,
as well as to your builder page: mr_modify1's Homemade Tools. Your receipt:
<div id="blocks"> <div class="block b1 pngfix"> <div class="bimg"> <div> <a href="https://www.homemadetools.net/homemade-chuck-setup-tool"> <img src="/uploads/252576/homemade-chuck-setup-tool.jpeg"/> </a> </div> </div> <div class="head pngfix"></div> <div class="left pngfix"></div> <div class="right pngfix"></div> <div class="blockover b1 pngfix"> <div class="title"> <a href="https://www.homemadetools.net/homemade-chuck-setup-tool">Chuck Setup Tool</a> <span> by <a href="https://www.homemadetools.net/builder/mr_modify1">mr_modify1</a></span> </div> <div class="tags">tags: <a href='https://www.homemadetools.net/tag/chuck'>chuck</a> </div> </div> </div> </div>
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Hi Mr_modify1
Thank you for your post.
Please forgive if I am missing something here? But this does appear to be a lot of work and trying to reinvent the wheel. I appreciate there is always more than one way to skin a cat.
There is no explanation in the video on how the stock was finally clamped concentric to the lathe centre line? Are you relying on the similar pressure being exerted on each jaw via the Chuck key, once the mandrel is removed?
The setting up of the four jaw Chuck can be easily achieved using just a 6” rule on the Chuck. The 4 jaws are set in position and a rule measurement taken from a known reference point on the Chuck. This reference point could be the outside of the Chuck itself or the rings in the face of the Chuck. Once roughly at the correct diameter/AF the distance between the opposite jaws can be measured again with the rule, the stock being machined can be slid into the jaws and lightly tightened. This will get you with in 0.010” / 0.25mm (even on a bad day.) Then you can use whatever method to trim the stock perfectly to the centre line of the lathe with a DTI.
I have added a link to show the process I use. Although the video shows rectangular stock being clocked it is exactly the same principle for clocking square bar.
I hope this is of interest and helps you in the future when clocking up stock in a 4 jaw. This will also help save you valuable time and materials, in making a mandrel for every size of stock you are likely to need in the setup of a 4 jaw Chuck.
https://www.homemadetools.net/forum/...041#post106204
Many thanks
The Home Engineer.
You still have to go thru the indicating process. I use the 4 jaw only if I have to use it. I always thought someone would come up with a self centering 4 jaw chuck but I have not seen one yet. There must be a better solution than all the measuring and indicating.
There are self-centering 4-jaw chucks. Like any chuck, if you get to only .003" runout, you have a really good chuck. Where a 4-jaw independent jaw chuck shines is in getting stock dialed in to under .001", or if you want/need to be fussier, even I can get to within .0001" in a couple of minutes. To help you speed it it, use two chuck keys on opposing sides. Best description of the process I've seen is here: https://littlemachineshop.com/images...4-jawchuck.pdf as the last few paragraphs of the pdf say, you can center a round bar, open two adjacent jaws a bit, and put a square (or octagon) bar of the same size in and tighten the two sides to be well aligned.Quote:
Originally Posted by mr_modify1
Bill
Thanks Bill.
Hi Mr_modify1
Thank you for the reply.
As WmRMyers has pointed out there are 4 jaw self-centring chucks.
A self centring 4 jaw is only as accurate as the stock being held. I often have to use shim to get all four jaws to contact a stock piece of square material. So my first choice for accuracy would be the 4 jaw independent chuck.
Where I find the 4 jaw self centring chuck really useful, is when several components need a shaft turned on a piece of square stock and the square is then required to to be machined in a second operating concentric to the shaft. This can save material and time rather than machining all from round stock. Or where the concentric accuracy is not critical ie: tee-bolts etc.
Therefore the 4 jaw self centring chuck is not often mounting on the lathe.
Another method is a lot more expensive but I find even holding square stock this is very accurate. Commercially made square collets like the 5C system or the Crawford multi-bore collets which I find to be very accurate. This accuracy is probably due the the amount of collect contact area with the stock. But again very expensive due to the amount of collets needed to cover stock sizes. Let alone purchasing the chuck body.
many thanks again but unfortunately the cheapest way to get square stock to run true is to setup in the 4 jaw independent chuck.
We all have to find away that suits are personal budgets and there is always more than one way to get the same result in Engineer.
The Home Engineer
Believe me, you don't want a self-centering 4jaw. The independent 4jaw is both more flexible and more accurate.Quote:
Originally Posted by mr_modify1
Centering work in the 4jaw can be made much less tedious with a few homemade tools and a straightforward procedure. You may want to read my procedure here...
https://www.homemadetools.net/forum/...aw-chuck-27241
With this procedure, another dead simple addition can make centering polygonal stock much easier...
https://www.homemadetools.net/forum/...al-stock-27183
-Easiest and most hassle-free method for indicating a 4-jaw independent (I've yet seen) is a 5 year old, 5 min long video from Joe Pie:
https://www.youtube.com/watch?v=WCei5GlEZ5g
ATB & Happy New Year!
Johan
The very best tips out there!
Here is a prime example of a thread hack, yet connects the range of suggestions accumulated by OP's post. Apology in semi-logical order of details, more overlaps than a line of senators beachside in Miami. (shudder :headshake: shudder)
The only reasonable justification of a self-centering 4-jaw is production work; the variety with master jaws switched out for tooling that holds a casting etc.
Only use encountered was turret lathes and stock serrated jaws running material, basically cube shape iron castings. The uncut base was faced whilst chucked on turned end in a 3 jaw; became a sealing flange with 4 bolt holes in corners. Terminology-wise that was more chucker than turret, individual parts vs bar feed.
FWIW, there are self centering 2 jaws, 3 jaws, 4 jaws, 6 jaws.
There are independent 3 jaws, and 4 jaws.
All available (with sufficient $$$.$$) in solid outside jaws, solid inside jaws, reversible jaws, and 2 piece jaws.
Here, they separate into plain jaws and stepped jaws. Plain jaws can be radiused for OD, or carry a narrow point, mainly accommodating wider range of diameters.
At this level, 2 piece jaws have about 3 patterns attaching top to master; slotted, keyed, 60° serrations.
Some models offer soft jaws and hardened jaws.
Those diverge once more into smooth jaws and serrated tooth jaws. Typically, serrated jaws are hardened, in generating incredible grip, they're marring the surface, an 1/8" of aluminum averts that.
On rare occasions, an independent 4 jaw will be run just opposing pair, fitted with tooling for really off centered needs.
By the time you get 16" swing, consider a crane. There are various lifting types, gantry's seem most practical.
At about 24" swing, starts another option. There are face plates with four bolt-on jaws for horizontal lathes, otherwise like vertical boring machines. Always hard, serrated, some reversible by removing and turning around. Used sets? Start around $2500.
For my $.¢, best choice is 2 piece jaws, supplied with reversible serrated hard jaws offers greatest flexibility. Whether 2-3-4 or 6 depends what machine I'll hang it on. If you acquire lathes, an operative search begins considering which variety of spindle design.
I buy used. A South Bend and Logan share threaded spindles, the real lathes D1-3 and D1-6. Easiest to mount, reversible rotation, most plentiful therefore most economical. Holding out on a rather exceptional 14", just because bolt on chuck; on faceplate, different than what's known as A-1 type.
The real 'trick' dialing in is visualizing what needs to happen movement wise of part, not indicator. Often, I start by NOT having the indicator touch all the way around. Makes the high side very apparent, especially on larger diameters. Mounted on cross slide, it's plenty fast to adjust contact to final it in.
Here are two well-knowns with impressive credentials. Watch all, it's entertaining, or skip to 4:50, then 8:50.
Hi DIYswede
53 years old and still learning. This is a great method for square stock. Thank you for posting
The Home Engineer
4 jaw scroll chucks do exist but I'm not sure why you would want one. The whole point behind general use of a 4 jaw is to get run out down to nothing or nearly so. Scroll chucks just are not that accurate even when new, with a little wear they can be terrible.Quote:
Originally Posted by mr_modify1
Lots of good points here but I need to pull out one little point below.
I would like to say always consider a crane if you have to strain even a little bit. We currently have a guy out at work and frankly being a bit of a gym rat, he is the last person you would expect to be injured or out of commission. It is just way too easy to have something go wrong while carrying significant weight.Quote:
Originally Posted by Toolmaker51
Some interesting information. Thank you.
I think a self-centering 4 jaw would be good for production in a shop that does a lot of turning of square stock. As long as you can tolerate the several thousandths of runout, just like with a 3 jaw chuck and round stock. Depends on how critical low runout is to your part, and how many of those parts you need to make. If you're making rocket parts, it's probably not going to be what you need. I'm probably never going to buy one. But I'm not doing production work, and I can take all the time I want to take to dial stuff in to ridiculously tight tolerances if I want to do it that way. YMMV! It almost has to.Quote:
Originally Posted by mklotz
Bill