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Help on getting a new 4 jaw chuck

Rixtools

Steel
Registered Member
#1
I am pretty new and am looking for a new chuck . I have been working with a borrowed 4 jaw and like the accuracy and want my own. My lathe is an early 60's Logan 1820 . I found this 6 inch 4 jaw chuck and backing plate on Ebay . Thoughts good bad ? And of course money is a concern . This chuck and backing plate is 140 plus 28 shipping. Thanks for any input.
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Dave Paine

Active Member
Active Member
#2
I do not have experience with the chuck you show. I have experience with Shars chucks and have been happy. They have 6in 4 jaw chuck onsale for $90 with $54 backing plate, so $144 plus shipping.

Whatever chuck you purchase, make sure you check if the jaws are reversible or whether you get internal and external jaws. Also ensure you get a chuck key. Sometimes included, sometimes extra.

http://www.shars.com/products/toolholding-workholding/lathe-chucks/6-4-jaw-independent-chuck-1http://www.shars.com/products/toolholding-workholding/lathe-chucks/6-4-jaw-independent-chuck-1
 

Silverbullet

Active Member
Active Member
#4
Did you try looking for used some are in good condition. Or look for one with the back all ready mounted there out there.
 

Rixtools

Steel
Registered Member
#6
Thanks guys. I have been zapped recently on buying things and am still a little sore in the rear. Not machine tools. So I am looking for something new that is not several hundred dollars. I am just having fun and learning with my Logan not trying to do any comercial work .
 

markba633csi

Active Member
Active Member
#7
I don't think you could go wrong with a Shars 4 jaw, I did have issues with one of the jaw sets on their 4" 3 jaw, poorly made (not ground square) and had some hassle getting them to send a replacement set. But the jaws are well hardened and the scroll is accurately fitted, not bad for 110$ incl backplate.
Mark S.
 

Wreck™Wreck

Active User
H-M Supporter-Premium
#9
Unless you do a good deal of square, rectangular or off center work buy a 3 jaw adjustable chuck, there are few things that are more tedious then having to indicate every single part that you put in a lathe.

Todays job was perfect for a 4 jaw, a rectangular steel part with a 1 1/2-12 thread in one end. This sort of thing is the only good reason to use one.
Indicate part, this takes longer then the threading.


Indicate the tool.


Set the tool height. The center of the spindle on this lathe is 8 1/6" from the ways, and no, I do not obsess over tool centering as this method has worked for me for 30 years.


Drill, bore then thread until the gauge fits, done! The set up takes longer then the work itself, if this part were round I would have had it adjusted in a 3 jaw in 10 minutes rather then 30-40. Don't use a 4 jaw unless it is the only way, as mentioned it is tedious in every way. There are eight of these parts, that is 3-4 hours of dialing in an independent chuck.
Be a machinist they said, it will be fun they said (-:

 

projectnut

Active Member
Active Member
#10
If you are only able to afford one chuck I would buy a 4 jaw independent style. An independent 4 jaw chuck can easily be adjusted to .000" runout. A standard 3 jaw scroll chuck usually has a runout of .001" to .003'. That may not sound like much, but it will make a big difference if you remove a part for inspection or reorient it for additional procedures. The odds of getting the piece back in the exact same orientation are slim to none.

In general a 3 jaw chuck is used when all operations can be performed with a single setup. In most cases it's wise to start with stock longer than the part you are turning. When the part is finished it should be parted from the stock remaining in the chuck to insure it is concentric to the axis of the spindle. If the chuck has .003" runout any portion of the part not turned will have the same amount of runout. Any hole bored through the piece will be concentric with the OD of the turned section, but be off center on the unturned portion.

Centering a 4 jaw chuck takes only a few minutes once you get used to it. I have 3 lathes and a dozen different chucks. All of the 3 jaw scroll chucks have .001" or more runout regardless of the manufacturer. About the only time I use them is when I'm making a part that can be done with a single setup. I always start with stock long enough the finished piece can be parted from the raw stock.

If you insist on a 3 jaw scroll chuck be sure to look at the "set true" or "adjust tru" styles. These style chucks can be adjusted to .000" runout after the part has been secured in the jaws. The downside to these style chucks is that they are about the most expensive on the market. As an example Shars sells a 6" 3 jaw adjustable style for $403.95.

http://www.shars.com/products/toolh...-0005-adjustable-universal-chuck-2-piece-jaws

The same size 3 jaw chuck without the adjustable feature runs $219.00.

http://www.shars.com/products/toolh...-cast-steel-self-centering-scroll-lathe-chuck
 

projectnut

Active Member
Active Member
#11
I forgot to comment about the chuck in your original post. Taking a look at it I would prefer a different style. The one you have chosen requires 2 sets of jaws. One for holding on the outside of a work piece, and a second for holding on the inside of a work piece. I have no problem with the way it functions (I do have several of this style), however my preference is to have a chuck with replaceable top jaws. This style only requires one set of jaws. They are unbolted from the base jaw and turned around for inside holding.

Here's a link to the style I'm referring to:
http://www.ebay.com/itm/6-4-JAW-SEL...300499?hash=item4841a9ec93:g:Aa4AAOSwTapV46Z1

The major advantage is that there is only one set of jaws. There's nothing to store in that "special place" until needed. In time you'll forget where that 'special place" is and spend more time looking for the jaws than changing them out. Also if in time you acquire more chucks you'll have to sort and identify which jaws fit which chucks. In addition I believe there are at least 500 or more different design of this style jaws. Finding a replacement could be a nightmare. As a side note I "lost" a set of inside jaws for several months. Finally deciding I must have inadvertently thrown them out I broke down and purchased a new chuck. I didn't have the new chuck 3 weeks when I stumbled across the "special place" where I'd stored the jaws.

The replaceable top jaws on the linked chuck are known as American Standard design. There are dozens of vendors that make replacement hard jaws and also soft jaws. While hard jaws are expensive at least they can be replaced. Soft jaws on the other hand are inexpensive. Some are as low as $50.00 a set. In addition I don't know of anyone that even makes soft jaws for the style chuck in your picture. I do have one set of soft jaws for an older chuck of that style. This is an older Union brand chuck that was ordered new with a second set of hardened outside jaws. They were then cut ground, and fitted with bolt on soft top jaws. I'm not aware of any manufacturers today that offer additional replacement jaws when ordering a chuck.
 

benmychree

John York
H-M Supporter-Premium
#12
I do not have experience with the chuck you show. I have experience with Shars chucks and have been happy. They have 6in 4 jaw chuck onsale for $90 with $54 backing plate, so $144 plus shipping.

Whatever chuck you purchase, make sure you check if the jaws are reversible or whether you get internal and external jaws. Also ensure you get a chuck key. Sometimes included, sometimes extra.

http://www.shars.com/products/toolholding-workholding/lathe-chucks/6-4-jaw-independent-chuck-1http://www.shars.com/products/toolholding-workholding/lathe-chucks/6-4-jaw-independent-chuck-1
I have never, in my nearly 60 years of machine tool consciousness seen a 4 jaw chuck, that does not have reversible jaws, not counting combination chucks. With used chucks, if MUCH used, the jaws will fit loosely in the body, making the OD end of the jaws bell mouthed, which will effect their accuracy in (attempting) to hold longer rounds or squares accurately.
 

4gsr

Global Moderator
Staff member
H-M Supporter-Premium
#13
I have never, in my nearly 60 years of machine tool consciousness seen a 4 jaw chuck, that does not have reversible jaws, not counting combination chucks. With used chucks, if MUCH used, the jaws will fit loosely in the body, making the OD end of the jaws bell mouthed, which will effect their accuracy in (attempting) to hold longer rounds or squares accurately.
It's like a 6-jaw but missing 2-jaws.:eek:
 

benmychree

John York
H-M Supporter-Premium
#14
It's like a 6-jaw but missing 2-jaws.:eek:
I realize the definition that you offer is correct, but still, I have never seen suchlike, and doubt that a US manufacturer has made one since the first world war; I have many old catalogs for machinery, all one sees is 3 jaw scroll chucks, and 4 jaw independent chucks and occasionally a 3 jaw combination chuck with screws rather than a scroll; we do not see 6 jaw scroll chucks until more recently. I cannot see why a 4 jaw scroll chuck would be of much use due to all four jaws coming together perfectly enough to avoid having at least one opposite jaw not close without a bit of clearance, especially on less than perfectly sized or imperfect squareness.
 

4gsr

Global Moderator
Staff member
H-M Supporter-Premium
#15
I recall seeing them somewhere in a catalog a few years ago. Cushman used to make the 4-jaw combination jaw chuck, which I've only see one in my life. My dad pulled it from a dumpster dive and later gave it away because he didn't want it, but kept the 4-jaw Cushman independent chuck. I think the Chinese are the first ones to come out with one. I personally don't care for it either. I'm happy with the 3-jaw chucks I have along with the 4-jaw independent chucks too.
 
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benmychree

John York
H-M Supporter-Premium
#16
I recall seeing them somewhere in a catalog a few years ago. Cushman used to make the 4-jaw combination jaw chuck, which I've only see one in my life. My dad pulled it from a dumpster dive and later gave it away because he didn't want it, but kept the 4-jaw Cushman independent chuck. I think the Chinese are the first ones to come out with one. I personally don't care for it either. I'm happy with the 3-jaw chucks I have along with the 4-jaw independent chuck too.
Amen!
 

Wreck™Wreck

Active User
H-M Supporter-Premium
#17
I recall seeing them somewhere in a catalog a few years ago. Cushman used to make the 4-jaw combination jaw chuck, which I've only see one in my life. My dad pulled it from a dumpster dive and later gave it away because he didn't want it, but kept the 4-jaw Cushman independent chuck. I think the Chinese are the first ones to come out with one. I personally don't care for it either. I'm happy with the 3-jaw chucks I have along with the 4-jaw independent chucks too.
Do you mean a 4 Jaw scroll chuck?
 

mksj

Active User
H-M Supporter-Premium
#19
Bison and few other manufactures still make 4 jaw combination chucks, if I just needed one chuck for everything it would be a combo. A few of the hobbyist use them. Below is the Bison 8", the scroll will repeat to ~0.002" and it takes about 30 seconds to dial it to nil with the independent jaws. The jaws are much slimmer then standard 4J independents, so you can grab stock down to 0.2". If you want to hold a large rectangular plate, a 4J independent with wider jaws would work better. I probably use my 5C the most, then the combo, and I have a Set-Tru 6" that I only use if I need to do a lot of repeat clamping for multiple pieces. The Set-Tru will repeat to better than 0.0004" so I set it once and leave it. The only time I will recheck it is when I reverse the two piece jaws, there is a slight variation on how they mount. Different people have different preference, so it varies based on what you do.
20170415_081356.jpg 20170415_081337.jpg
 

Splat

Active User
H-M Supporter-Premium
#20
IMO you don't have to spend a lot to get a decent enough 4-jaw independent. Unless the jaws are really shoddily made or worn you'll be dialing in the work anyway. I don't know anyone with a Shars chuck so I can't speak to their quality but for myself, I would go with something from Gator or Fuerda. I don't like taking a gamble on a used chuck I cannot inspect in person so used for me is pretty much not gonna happen.
 

Rixtools

Steel
Registered Member
#24
This has turned into a very informative thread. I do like the 4 jaw combination. That is hands down the coolest. Probably lots of $$ for that one. But I am still going with a 4 jaw. Good advise not to be too cheap, so go middle of the road cost wise. And steel not aluminum, good advise there.