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SharsTool
04-17-2010, 11:02 PM
Hi Everyone,

This is Joey again and hopefully this time I would not create such a stir like last time. :D I recently received a suggestion from a potential customer about bringing in a 4" or 5" 6 jaw lathe chuck, cast iron chuck body, plain back, accuracy to .0005". I want to take this chance to ask how you guys think and determine if there is a market demand on this. i am not trying to spam this time, just want to know your guys' opinion.

Bruce Griffing
04-17-2010, 11:14 PM
That accuracy is difficult to achieve. The best you can do is an adjust-tru type of chuck that can be centered, if necessary, for each diameter of workpiece. I do think there would be a market for an adjust-tru type of chuck.

SharsTool
04-17-2010, 11:37 PM
Hi Bruce,

thank you for your comment. The chuck I am thinking about is an adjust-thru chuck.

PixMan
04-17-2010, 11:54 PM
That accuracy is difficult to achieve. The best you can do is an adjust-tru type of chuck that can be centered, if necessary, for each diameter of workpiece. I do think there would be a market for an adjust-tru type of chuck.

I don't know about a 6-jaw chuck's accuracy right of the box, but I've got a Pratt Burnerd 10" Super Precision 3-jaw chuck (in D1-6 mount) that runs out less than .0003" on every diameter I've ever put in it. :)

It was new old stock from a dealer doing away with their manual machine lines, and had actually been dropped on one jaw hard enough to crack it through at one of the bolt counterbores. Still runs as close to perfect as I could wish for, and I got it for the princely sum of $250.

Bruce Griffing
04-17-2010, 11:58 PM
PixMan-
I think a scroll chuck that holds that accuracy over a range of diameters is a pretty rare item.

PixMan
04-18-2010, 12:15 AM
PixMan-
I think a scroll chuck that holds that accuracy over a range of diameters is a pretty rare item.

Indeed it is, and that's why it's never going anywhere out of sight. ;)

RobbieKnobbie
04-18-2010, 12:40 AM
I thiink you'd probably sell a good number of them... depending on price, of course.

Offering fitted backs would sell more.

NBbrad
04-18-2010, 12:41 AM
cast iron chuck body, plain back, accuracy to .0005". I want to take this chance to ask how you guys think and determine if there is a market demand on this.

Why cast iron instead of steel? Cheaper?

Accuracy to 0.0005" is ambitious. Even well known chuck manufacturers will only claim repeatability of 5 tenths with adjustment required at every diameter, and I never see accuracy claims. If it turns out to be anything like the 6" 3-jaw that I bought from you a few years ago, it'll have a sticky scroll and questionable repeatability.

What's the ballpark price you're thinking about including the backplate? If it's worth a damn, it'll probably be too expensive for the types of lathes that use 4 or 5 inch chucks. My 2 cents.

SharsTool
04-18-2010, 12:56 AM
Offering fitted backs would sell more.

Hi RobbieKnobbie,

thanks for the comment. what type of back plate mounting would you recommend that I should start with?

SharsTool
04-18-2010, 01:15 AM
Why cast iron instead of steel? Cheaper?

Accuracy to 0.0005" is ambitious. Even well known chuck manufacturers will only claim repeatability of 5 tenths with adjustment required at every diameter, and I never see accuracy claims. If it turns out to be anything like the 6" 3-jaw that I bought from you a few years ago, it'll have a sticky scroll and questionable repeatability.

What's the ballpark price you're thinking about including the backplate? If it's worth a damn, it'll probably be too expensive for the types of lathes that use 4 or 5 inch chucks. My 2 cents.

Hi NBbrad,

cast iron body has lower cost than steel body. Bison is a good example to compare the price between a cast iron body and steel body.

5 tenth runout is achieved by 4 micro adjustment screws on the back of the chuck.

i do not have a price yet as i am still on the research process, but I am a competitive person in nature. can you tell to me on what type of application or scenario would one wants to use a 6 jaw chuck? And what type of lathe would you think one would outfitted with a 5" 6 jaw scroll chuck?

Black_Moons
04-18-2010, 01:28 AM
Ok heres a problem for ya shares

While a 3 jaw you can 'adjust true' and it does not matter how good the scroll is because with 3 jaws, all 3 jaws allways touch and clamp down simutaniously.

With a 6 jaw, if the scroll is not perfict, the jaws will not clamp accurately and at the same 'time'
As in, only 3+ jaws will clamp down, and the other 3~ won't.

Do not assume 'set true' screws compensates for a poor scroll with a 6 jaw, unless you plan to make each of the 6 jaws independantly tightened (ie no scroll)

As for uses of a 6 jaw:
6 jaws are best for delicate work, like thin walled pipe, as it can grip it better without deforming it due to extra support.
Poorly designed 6 jaw scroll could result in dangerious work comming loose during turning operations if not all the jaws are supporting the work equaly.

I might be kinda intrested in a independant jaw 6 jaw with set true screws however, for when I get around to making a wood lathe, as it could hold irregular work easily and be dialed in easily.

dp
04-18-2010, 01:32 AM
I've been wondering about the clamping force on 6-jaw chucks, too. I can see an advantage for tubular work but 6 jaws in a scroll chuck is a 3-jaw in disguise. The trick is to know which three are doing the work.

torker
04-18-2010, 01:37 AM
Hi NBbrad,

cast iron body has lower cost than steel body. Bison is a good example to compare the price between a cast iron body and steel body.

5 tenth runout is achieved by 4 micro adjustment screws on the back of the chuck.

i do not have a price yet as i am still on the research process, but I am a competitive person in nature. can you tell to me on what type of application or scenario would one wants to use a 6 jaw chuck? And what type of lathe would you think one would outfitted with a 5" 6 jaw scroll chuck?
4 micro adjust screws on a 6 jaw??? What am I missing here?

SharsTool
04-18-2010, 02:26 AM
Hi Torker,

the 4 micro adjustment screw is located on the back of the chuck in a bolt circle pattern with 90 degree apart of each other. Adjusting the 4 screw will bring the center of the chuck closer to the center of the lathe spindle, thus achieving reduced runout.

SharsTool
04-18-2010, 02:33 AM
With a 6 jaw, if the scroll is not perfict, the jaws will not clamp accurately and at the same 'time'
As in, only 3+ jaws will clamp down, and the other 3~ won't.

Do not assume 'set true' screws compensates for a poor scroll with a 6 jaw, unless you plan to make each of the 6 jaws independantly tightened (ie no scroll)



Hi Black_Moons,

thanks for your tip and I will keep that piece of information in mind.



As for uses of a 6 jaw:
6 jaws are best for delicate work, like thin walled pipe, as it can grip it better without deforming it due to extra support.
Poorly designed 6 jaw scroll could result in dangerious work comming loose during turning operations if not all the jaws are supporting the work equaly.


thank you for sharing the application advantage of a 6 jaw chuck with me. and can you tell me why would one person pick the 5" chuck over a 6" chuck? Is there some kind of reason that one must use a 4" or 5" chuck?

NBbrad
04-18-2010, 03:16 AM
cast iron body has lower cost than steel body. Bison is a good example to compare the price between a cast iron body and steel body.

Cast iron may be a cheaper, but it isn't the choice material for high speed rotating chucks.


can you tell to me on what type of application or scenario would one wants to use a 6 jaw chuck? And what type of lathe would you think one would outfitted with a 5" 6 jaw scroll chuck?
...
can you tell me why would one person pick the 5" chuck over a 6" chuck? Is there some kind of reason that one must use a 4" or 5" chuck?

I don't mean to be rude, but these are very elementary questions that any serious buyer would be able to answer. How can you be qualified to design and make these products if you don't know what they're used for?

My opinion is that the majority of people looking for small, lightweight chucks are better off using 5C collet chucks. Simple to use, readily available, cheap, lightweight, and low cost due to simplicity rather than shortcuts in manufacturing. Independent 4-jaw chucks suffice for special applications. A very high quality 6-jaw has its place for guys who do precision delicate work, but it seems to me you're much more concerned about low price than quality.

danlb
04-18-2010, 03:26 AM
Shars does not make them, but they do supply them. I'm just a customer, and I have bought from them a few times.

I have been looking into 4 inch, 6 jaw chucks too. I have a 7x12 lathe, and I frequently work on flashlights among other things. I only have 3.5 inches between the center of the lathe and the ways, so having a 5 inch chuck means that the jaws, when extended, can extend only 1 inch before something breaks.

The folks using bison 6 jaw set-tru on the flashlight forum are very, very happy with the repeatbility and the work holding. Of course, they are using 6 to 8 inch chucks on larger machines.

I have not located a 4 inch 6 jaw yet.


Daniel

dp
04-18-2010, 03:56 AM
I don't mean to be rude, but these are very elementary questions that any serious buyer would be able to answer. How can you be qualified to design and make these products if you don't know what they're used for?

One purpose of such queries is to debias the internal "common knowledge" of a company. It is a good assumption that one is not the expert they presume themselves to be, and to test that is a very good idea. Companies that think they've nothing to learn are doomed. I'm still around but I've worked for a number of such companies that are not.

Ian B
04-18-2010, 04:05 AM
The main use for 6 jaw self centring chucks seems to be for holding thin walled components. In this case, won't all six jaws be in contact with the work, as the work will flex (slightly) to make up for any inaccuracy in the chuck jaws / scroll?

Ian

MuellerNick
04-18-2010, 04:43 AM
A chuck with a CI-body is cast (who wonders?), one with a steel body normaly is drop forged. That makes one part of the price difference. The other one is, that a steel body is hardened and then ground. CI bodies lack the hardening. So they won't keep their precision as long as the steel body ones.


Nick

JCHannum
04-18-2010, 09:07 AM
The main advantage of a six jaw chuck is in clamping delicate parts such as tubing. They spread the clamping force over a wider area. Two things to keep in mind in choosing a six jaw over a three jaw are that they do not have the gripping power of a three jaw and they will not close on as small a part as a three jaw.

The jaw width is probably why you will not see a six jaw smaller than 5" or 6". The face of the jaw has to be wide enough to provide some gripping area and there has to be enough material left between the jaws to provide some strength for the chuck.

A six jaw is just a three jaw with three extra jaws. On the Buck at least, the three jaw chuck jaws will interchange. The additional slots for the added jaws serve to weaken the face of the chuck. This makes them more fragile than the corresponding three jaw. Using cast iron would make an even more fragile chuck. I would strongly advise against the purchase of a C/I six jaw chuck regardless of any accuracy statements.

gda
04-18-2010, 10:06 AM
The market for that small chuck is the micro hobby machine, like import 7" or older craftsman 6" lathes. I would bet that the price for the chuck would have to be pretty low for this crowd.

A cast iron body scares me as well. Look at problems people post about breaking their cast import vices. Add rotation and it sounds like a hand grenade waiting to go off. At least with steel it bends befoer it breaks, CI just breaks. Now there are many different grades that can come close to steel, but do you know which one to pick, and are you sure that is what you are getting? My work has outsourced OEM machine parts to China and China can not get the same materials, and we also catch them making substitutions.

( I have 2 6 jaw set tru chucks: 6" bison, 9.5" buck )

SharsTool
04-18-2010, 11:04 AM
Using cast iron would make an even more fragile chuck. I would strongly advise against the purchase of a C/I six jaw chuck regardless of any accuracy statements.

Hi Jim,

Thank you for sharing more detail on the 6 jaw advantage and I will watch for those two things you mentioned.

And after review your comment & GDA's comment, I will definitely consider a steel body chuck only.

SharsTool
04-18-2010, 11:13 AM
The market for that small chuck is the micro hobby machine, like import 7" or older craftsman 6" lathes. I would bet that the price for the chuck would have to be pretty low for this crowd.

Hi GDA,

thank you for giving me the example of the potential market.


A cast iron body scares me as well. Look at problems people post about breaking their cast import vices. Add rotation and it sounds like a hand grenade waiting to go off. At least with steel it bends befoer it breaks, CI just breaks. Now there are many different grades that can come close to steel, but do you know which one to pick, and are you sure that is what you are getting? My work has outsourced OEM machine parts to China and China can not get the same materials, and we also catch them making substitutions.

( I have 2 6 jaw set tru chucks: 6" bison, 9.5" buck )

After reviewing your comment & JCHannum, I will look into steel body chuck only. and what type of work do you typically do on your bison & buck chuck?

gda
04-18-2010, 11:44 AM
and what type of work do you typically do on your bison & buck chuck?


Well, what I do with the chucks and what they ideally for are 2 different things. The 6" Bison is new I use the 6" Bison for just about everything with the following exceptions: 9" Buck if the part is bigger (like 4.5" diameter), or if it a dirty job like Cast so I can keep the Bison Clean. I have a 8" 3 jaw that I reversed the jaws and use for parts larger than 4". I have a 8" 4 jaw that I have not used yet since I also have a mill and a boring head that I would probably use first. For small parts that I don't want to mark I use 5C collets wiht a lever collet closer. (you can also change the part without stopping the lathe). These are all for a Clausing 12" lathe.

For my smaller 9" south bends I use regular 3 jaw and 4 jaws chucks, an import 5C closer that I have for sale since picking up a Hardinge Speed Chuck.

I mostly make tools, Go Karts, car parts, and parts for other machines, all for personal use.

SharsTool
04-18-2010, 01:21 PM
A very high quality 6-jaw has its place for guys who do precision delicate work, but it seems to me you're much more concerned about low price than quality.

Hi NBbrad,

I am into quality and I am trying to improve my tooling, and it's part of the reason I sign onto this forum to hear your opinion.

examples that I have done to improve my tooling:

1) ER collets: I have switched 3 vendors before settling into the current vendor.

2) CNC CAT / BT taper tooling: I went through 4 vendors, and before I made the decision to pick the current vendor, I visited and stayed at the manufacture's plant for a week and wanted to learn more in depth about their manufacturing process. I have observed that how they have treated the tooling they make like a baby, and it shows to me how they care about their stuff and this goes a long way into every manufacturing process. Every qualified manufacture would have the right equipment (CNC mill, CNC lathe, grinder) in making and inspection equipment, the difference between one manufacture and another is their personnel.

3) Mill Vise (oh boy, here we go again :) I will keep it short this time): I have switch 4 vendors and now I have two vendors for my vise: one is for the low price market. and another vendor's vise is made in Taiwan and carries very accurate repeatability in clamping. The vise that is made in Taiwan are the new vises that I have, they are showcased on the flashing banner above. And I have already addressed the vendor about the concern on vise key and cast body and we are getting that problem fixed. I have sold quite a few of the new vises (SV, SPV, SDV) since March to different group of user, IH and CNC shops, and I have heard nothing but praises on them.

I am a competitive person in nature, and I will always try to improve. If I hear something is not right, then I will correct it with every resources that I have.

BadDog
04-18-2010, 01:59 PM
Going off topic a bit, but speaking of ER collets, how about getting some that are actually nominally sized as fractional imperial. Most inexpensive ER collets are actually relabeled metric, so getting it to hold a fractional imperial tool is far less than ideal. Considering how often this comes up, I think you might find this a bigger market than an inexpensive 6 jaw for micro lathes...

Rustybolt
04-18-2010, 02:22 PM
Run half a dozen samples or so and see how they hold up in a real life situation.
I have to admit I like my Buck 5 and 6 inch adjusttrue chucks.

Black_Moons
04-18-2010, 03:04 PM
SharsTool: Commitment to improving quality is commendable.

the last 5C collets I bought (I think from someone else), all the threads had little nicks in them like they had been on the worlds roughest assembley line before hardening. some gouges so big they looked like they had to of been droped.. had to get 4 replaced.. seller did so freely, but still somewhat annoying.

So yes, how they even handle items beween manufacturing stages can be important.

the reason for wanting a 4" vs 5" chuck mainly has to do with what size lathe they have, and to a lesser extent what size work they need to turn.

a 5" chuck is not a great fit to a 7" max diamiter lathe (chuck too big), because usally the chuck jaws protrude from the chuck body when fully open, and this would hit the ways of the lathe. And note that they do this before the chuck is even fully open.

Of course, I think 7" is about the smallest hobbiest lathe out there, and most are more like 9"~12"

a 4" might be a little more suitable for a 7".. but anything larger likey wants a 5" or even bigger. my 12" lathe really wants a 8" or so chuck. 5" would just seem to small...
I'll also note that after 8" chucks they start getting too heavy for one person to install!

12" is about the biggest common hobbiest lathe too btw. a few people own 14" but the cost is like twice that of a 12" for little additional features, so they are not super popular.


There are some people who work on the tiny sherline lathes and such but thats more like wanting a 2" chuck. And they likey want precision due to a lot of work being.. well, tiny precision work.


As for buying a smaller chuck, say a 4" to put on a 12" lathe, That could be desireable when working on very small work, because it will typicaly close to a smaller diamiter to grip smaller work.

Of course, you could just make extra 'pointy' jaws for the 5" 6jaw to grip small diamiter work and then we would'nt need to buy the 4", just more jaws

And if you wanted to wow us, Sell '2 part' jaws as an option for it.
Its not because we like taking jaws apart to reverse them, its because we like to make new jaws out of aluminum for speciality parts. (Super thin disks, odd shaped parts if we mill the jaws too), repeative parts, etc)

And when you make softjaws outta aluminum and turn as exactly needed, even a chuck with a poor scroll will lock down on the work perfictly, because they jaws where made with 0 runout at the desired diamiter. .. Though I still like the idea of a cheap independant 6 jaw more then a cheap scroll 6 jaw.

Infact I don't think I would buy a cheap 6 jaw with a scroll just because I know there would be no getting around the fact the scroll is.. cheap. Id wager that 90% of the 'quality' of those expensive 6 jaws is the fact the scroll is made very accurately and out of high quality materials.

And while in a shop envorment, having the scroll close all jaws at once is a super time saver, HSM tend to be more fussy about accuracy and marring up surfaces and don't mind a little more setup time.

PS: talking on the forum and asking questions = very awsome on topic way to get word out about your products. We are here to talk about mechining and fix problems and find solutions. Not technicaly to buy stuff, untill we find a problem that stuff is required to fix.

gwilson
04-18-2010, 03:56 PM
I think it is very good that Shars seeks our advice,and seeks the best vendors. I know that quality control is always difficult to get manufacturers to stay on top of,most especially on less costly items. I hope you keep it up.

I have a friend who gets many products made in China,and elsewhere. He has shelves full of progressions of really fouled up products,gradually becoming what he wanted. He's constantly going to China getting things straightened out.

lost in la
04-18-2010, 04:03 PM
Hi Joey
If you are interested in improving your tool line, why don't you buy more American made tools. We are out there.

I would appreciate a chance to be included in your cataog.
Thanks
John Fisher
www.fishermachine.com

Video Man
04-18-2010, 04:05 PM
Note to Shars, good on you to think of marketing better quality chucks. Might point out that Grizzly lists very similar chucks in their 2010 catalogue, so from a marketing standpoint you might look at their pricing and plan accordingly...they sell a variety of backplates for plain back chucks (in partial answer to your question) and also ready-made D-Camlock chucks as well. I am assuming you would have to compete with them on the price and variety of product.....

NBbrad
04-18-2010, 04:20 PM
examples that I have done to improve my tooling:
-snip-
1) ER collets: I have switched 3 vendors
-snip-
2) CNC CAT / BT taper tooling: I went through 4 vendors,
-snip-
3) Mill Vise ... I have switch 4 vendors

I think the reason why you're constantly switching vendors is because you're using your customers to do your testing and quality control rather than inspecting products yourselves and rejecting vendors outright.

I agree with the others here that discussing ideas with the public is a great way to tailor products to the market, but you need to have a certain amount of expertise to begin with.

Mark K
04-18-2010, 05:27 PM
Black Moons, well said.

Two features of a 5-inch universal chuck are of value (admittedly marginal) on a 7 inch lathe. The larger chuck allows more secure holding of larger work, because the jaws protrude less from the chuck body in the OD orientation. And, the center hole tends to be larger than that in a 4" chuck. That allows deeper chucking and less overhang. Of course, the chuck itself has more mass and overhang, and rpm must be watched.

So, a key feature for a 5-inch chuck is a larger center hole. My 4" chucks usually have 1" holes, as do some 5-inchers. My Pratt-Burnerd and Bison 5" chucks have 1.26" holes. That is one of the first features I check when considering a chuck.

Mark

johnnyd
04-18-2010, 06:12 PM
As a "hobby machinist"...,I got tired of trying to "tweek" my 3 jaw Buck chuck & decided it was time to upgrade.
After talking with a Bison rep at Cabin Fever one year, he turned me on to the "combination" chucks. They're only available in 4 jaw. I fell in love with them after the very first use. (I now own a 5",6",& 8")
If you made a 6" three jaw combination chuck with 2 piece jaws, (that's affordable) I'd be all over it.
I don't know of anyone who currently makes a 3 jaw combination chuck.

That's my 2 cents worth.:D

John

Robin R
04-18-2010, 10:14 PM
A type of small 6 jaw chuck that Shars used to sell but is no longer listed, are the ones with jaws that project farther out for sharpening drills. I for one would be interested in one that had a through hole of 1.25"-1.5", which would likely be about 6".

While there is a thread about Shars on the go, I'd like to suggest offering USPS shipping as an option. Canadian customers get really hammered by the brokerage charges from carriers like USPS, consequently I order less from vendors in the US. HH Industrial Products recomends shipping by mail for their Canadian customers, so though their prices are sometimes a bit higher I'm more inclined to use them.

SharsTool
04-18-2010, 10:17 PM
Going off topic a bit, but speaking of ER collets, how about getting some that are actually nominally sized as fractional imperial. Most inexpensive ER collets are actually relabeled metric, so getting it to hold a fractional imperial tool is far less than ideal. Considering how often this comes up, I think you might find this a bigger market than an inexpensive 6 jaw for micro lathes...

Hi BadDog,

going off this threads' purpose a little, & thanks for bringing this up about ER collet. I noticed that problem before and my current stock of ER collet are true fractional imperial size. I randomly check the ER collet by holding a US made end mill, which has a shank tolerance of -.0001, -.0004".

SharsTool
04-18-2010, 11:31 PM
Note to Shars, good on you to think of marketing better quality chucks. Might point out that Grizzly lists very similar chucks in their 2010 catalogue, so from a marketing standpoint you might look at their pricing and plan accordingly...they sell a variety of backplates for plain back chucks (in partial answer to your question) and also ready-made D-Camlock chucks as well. I am assuming you would have to compete with them on the price and variety of product.....

Hi Video Man,

thanks for your reference on Grizzly's chuck. I have their catalog 2010 in my office and will definitely look this up.

SharsTool
04-18-2010, 11:48 PM
And if you wanted to wow us, Sell '2 part' jaws as an option for it.
Its not because we like taking jaws apart to reverse them, its because we like to make new jaws out of aluminum for speciality parts. (Super thin disks, odd shaped parts if we mill the jaws too), repeative parts, etc)

I'd wager that 90% of the 'quality' of those expensive 6 jaws is the fact the scroll is made very accurately and out of high quality materials.



Hi Black Moons

I want to thank you for the insight you share and I will definitely read it over again to digest it.

the "2 part" jaws you are talking about, is it the American standard tongue and groove design? If it's, that is what I have in mind about the 5" 6 jaw chuck.

and thanks again for pointing out the scroll's importance, I will pay close attention to that.

SharsTool
04-18-2010, 11:55 PM
Hi johnnyd,

thanks for bringing my attention to the Bison combination chuck. I will put that on my wish list as well. :D Not sure if I can get them, but I will look for them.

SharsTool
04-19-2010, 12:02 AM
Hi RobinR,

off this thread's topic, we do ship USPS regularly to customer in Canada and other countries. However, my website can only use UPS as a shipping calculator. If for now, please email us your order and we can quote out the shipping charge by USPS flat rate box. and I am working to include USPS flat rate box as a shipping service for both domestic and out-of-country order.

PixMan
04-19-2010, 09:29 AM
I have bought from you before and was happy with the product (MT4 live center). I would've loved to have the option of buying US made, and gladly paid a couple of dollars more for it. Do talk with Fisher, as their stuff is of exceptional quality with a surprisingly competitive price structure.

I think if you could offer (as a big catalog/internet house does) the choice between USA or "quality import". In short order you should see the numbers justify keeping both or not. I know which I would choose.

Easy for me to say, but I don't know how you prioritize what you carry.

squirrel
04-19-2010, 12:10 PM
Hi Joey
If you are interested in improving your tool line, why don't you buy more American made tools. We are out there.

I would appreciate a chance to be included in your cataog.
Thanks
John Fisher
www.fishermachine.com
John, Your products are excellent!! You sent us some samples a year or so ago and I wanted to place them in our catalog. Some one here tried to place an order but got hung up because you did not have a fAX or take Credit Cards, I don't remember which but if things have smoothed out let me know and we will place an order.

Regards,
Fred

Thorn3
04-21-2010, 01:44 AM
I would suggest the sale of 2", 3", 4" and 5" 'true turn' type chucks for the hobby and small machine tool market. Companies like Bison and Buck etc., only cater to companies that use larger machines that have very demanding needs, such as high speed, high loading production methods. That leaves the home machinist and hobby machinist market out of the loop. There are more of 'us' than there are of 'them'. So why isn't 'our' market being filled with tools that we want or need?

It is my belief the anyone that pays for a Bison, Buck or other high end, drop forged steel chuck, for hobby/home machine use is either wealthy or simply made a 'choice' that suits them personally. In my opinion, for a small machine, it is serious overkill. Most hobbyists or home shop machinists don't use high end machines that exceed the more common 7 X 12 and 9 X 20 machines. None of the big boy companies cater to such machines. The cost of just one of their chucks far exceeds the cost of the machines themselves and do not offer any benefit for the cost. Most hobby or home machinist lathes do not exceed 2000 RPM. They don't need to. Who needs drop forged steel chuck bodies for such lathes? Nobody. What makes some people think that anything less than drop forged steel is necessary for chucks? This brings me to my next point.

Pure cast iron is out of the question. 'Semi-steel' is what most home/hobby machinists would want and need for a chuck body (in my opinion). For those that don't know what semi-steel is, it is an alloy of iron and steel. Very rugged for anything a home/hobbyist machinist would want or need. This material is also less than half the cost of drop forged steel, yet more than rugged enough for our uses.

Just because an individual does hobby or home machining tasks, doesn't mean they don't need or want 'options'. Presently, the market does not offer options. You either buy a chuck that is what it is, or you are simply out of luck. I believe this leaves the greater portion of the market dissatisfied with the products available to them.

Do I need or want concentricity greater than .003"? Most certainly! Most of the parts I make require machining on both ends of a part and tight tolerances. For the type of parts that many machinists make, .003" is way off and lacks anything even remotely close to repeatability. Some people simply don't care if their tolerances are tight or not. So be it. That is their choice. But many do want tighter tolerances. This is where 'options' comes in. We should have the choice as to how accurate our chucks are. This is why 'true turn' type chucks should be the norm, no matter their diameter. Wow... four set screws to achieve this. Does that warrant a price tag that is more than double a chuck that does not have such screws? Of course not. There is no reason why a 'true turn' type chuck is not the norm. In fact, it should be a standard. How can this possibly be argued? 4 drilled and tapped holes, with four set screws. How complex is that and how much could that possibly add to the cost of the chuck? If someone wishes greater accuracy, they may utilize this 'option'. If they don't... so be it. At least the option should exist. I don't want or need someone telling 'me' that I don't need this. They are not 'me' and thus do not know know 'my' needs. Options are important and are based solely on individual opinion.

Most small machines come with threaded spindles. with 'any' threaded component, errors will exist from one machine to the next. For instance, my 9 X 20 lathe (G4000) came with a 3-jaw chuck, mounted on its mounting plate. The mounting plate was 'not' machined on 'my' lathe. Thus, it was out by .004". You could actually see it was out, without even using a dial indicator. The boss the chuck mounts too was also out by .002". As a result, the chuck, which has a tolerance of .003", placed the total radial run-out at .009". Is this acceptable to any hobby/home machinist? I would think not. If the chuck was a 'true turn' type, these errors could be compensated for and brought to any level of accuracy that the owner wishes.

Back plates should be offered in two forms. One is finished. Inaccuracies can be adjusted out through the chuck. The other option should be an unfinished back plate, so a person can 'choose' to machine it specifically to their lathe.

Scroll plates: 'Any' scroll plate should be machined with care. After all this is what controls the movement of the jaws. They should be steel only, hardened and ground. Using any decent, modern CNC machine, such a scroll plate is not an expensive component to make. Aside from that, even a cheap scroll plate is acceptable and will work well, provided that the machinist keeps it clean and well lubricated. After all, the chuck itself should be adjustable to true it up.

Jaws: All jaws should be standardized to two piece. A master jaw and a reversible jaw. This offers options to 'any' machinist, for 'any' machining need. The jaws can not only be reversible, but replaced with a variety of jaws, be they hardened or soft jaws. Custom/home made jaws of different shapes can also be used. Once again... 'options'. Such options should not be an extreme expense. They should be the norm.

Chucks should be available as above described, in not only different diameters, but in different jaw counts. 2, 3, 4 and 6 jaw are most common and should all be available.

6-jaw chucks are an invaluable tool for those that work on delicate or thin walled parts. They are also invaluable in finish machining due to their basic characteristics of producing less deformation of the part or surface, due to distribution of clamping forces over a greater area. Once again, this is not an opinion, it is simple fact.

All jaws should be finish machined 'in' the chuck, not externally to it. This insures greater concentricity. Then, simply take the chuck apart, clean it thoroughly, then lube and reassemble it. This is... or should be.. common practice for anyone producing or using a chuck in the first place. This method not only increases the usable lifespan of the chuck, but retains greater accuracy. In simplicity, it is called 'taking care of your tools'. I have seen high end chucks for sale, that look as though they have been sitting on the bottom of the ocean for a few decades. The owner then tries to pass this chuck onto someone that doesn't know the extent of the damage done to the chuck, from lack of care. My point being that even lower grade alloys used to make chucks, is completely satisfactory, as long as you take care of it. With 'true turn' chucks, taking care of the chuck is that much easier. After dis-assembly, cleaning, lubing and reassembly, it can still be trued up. Once again, this is an option that 'all' chucks should have, no matter their diameter or jaw count.

Costs: Such chucks should not cost much more than their lesser counterparts. With present day CNC machining centers, creation of such chucks should not be an issue. High cost of chucks is often not due to the 'quality' of the chuck, but to the overhead of the company that makes the chucks. I would be more than willing to pay $300-$350 for a 5" chuck, as described above. Smaller chucks of the same type should of course have lower prices. There is no reason such chucks cannot be made with quality, for that price, using semi-steel as the base alloy for the chuck body. Some companies make them already for that price. They just don't make them smaller than 6" in diameter, which places them outside of the home/hobbyist use.

Who should make them? Anyone. Any small job shop or company is preferred. Anyone who actually cares about what they are doing and knows what they are doing. In fairness to all other countries, they can make good parts/machines too. I am not against them. But they have to 'want' to deliver quality, as a matter of work ethic and honor, not spit out junk. All that does is waste resources, time and money. The average American job shop or small company actually takes pride in their work. This shows in their products. That is all we ask. Give us a good product line with options and acceptable/reasonable quality for the money. Any American companies out there that want to fill the market? Then do it!

So, is there a market for options in small machines, chucks, tooling etc? Of course there is. Any company that ignores this market, is simply losing out on a great opportunity.

MuellerNick
04-21-2010, 04:30 AM
Bison chucks start at 80mm.
A chuck half the size of any reference won't cost half the price. Work is almost the same. For example a drop forged jaw's cost (Bison) is more defined by the process and not the weight of raw material.


Nick

MichaelP
04-21-2010, 10:46 AM
Joey,

You mentioned that the adjusting screws are located on the back of the chuck (so, eventually, they will be covered by the back plate). What purpose will they serve in this configuration if you don't have an easy access to them (even if the back plate has access holes)? How do you envision one centering the work?

MuellerNick
04-21-2010, 11:42 AM
The adjustment screws are at the rear of the circumfence. Not at the backplate's back.


Nick

MichaelP
04-21-2010, 12:06 PM
That's where I'd expect them to be. :)

However, the original description doesn't sound obvious:

"5 tenth runout is achieved by 4 micro adjustment screws on the back of the chuck".

"...the 4 micro adjustment screw is located on the back of the chuck in a bolt circle pattern".

Toolguy
04-21-2010, 12:43 PM
I feel that thorn3 has made many excellent and valid points. Thanks for that post. I happen to agree.

Thorn3
04-21-2010, 03:06 PM
True turn set screws are located towards the 'rear' of the chuck, located along its outer (side) surface, not on the actual back face of the chuck. You have access to them in much the same manner as you have access to the scroll adjustment.

The boss that seats in the back end of the chuck, is what the set screws push against. Much like adjusting the tailstock on a lathe, where two opposing screws push towards each other, against a common block. With the true turn setup, there are four screws, so it is like adjusting an independent, four jaw chuck, only you are moving the entire chuck, not just its jaws.

The set screws offer only a means to move the position of the chuck, relative to the back plate. These screws are not intended to withstand any great loading. Once the chuck is centered, the main lock down bolts hold the chuck securely, as they typically do.

The reason the set screws are able to adjust the chuck position, is due to the fact that the boss that seats in the back end of the chuck, is smaller in diameter than the recess in the back of the chuck. This offers some play, where the chuck moves in reference to the back plate. This is different from non-true turn chucks. Non-true turn chucks typically have a difference of only .001" between the boss and the recess in the chuck, or utilize an interference fit to hold the chuck centered on the back plate.

Sure... all facets of a manufacturing process and retailer markup will determine the final cost of the chuck, but smaller chucks should cost less than larger chucks for exactly those reasons. Less material, a less expensive material. Shorter processing time, less tooling loss/cost, more produced per hour, less overhead if it is a smaller company, which will lead ultimately to less markup (or so we would hope), bringing true turn chucks in a variety of sizes into the 'practical' price range of the average small machine user.

Bison and Buck, etc., don't take orders directly, so people have to go through a supplier. All suppliers I have contacted over a weeks time, have told me that they don't and won't sell chucks less than 6" in diameter. They are not even aware that any company makes true turn chucks smaller than 6". If any of the companies make true turn chucks in sizes less than 6", suppliers are either not aware of them, or are simply not informed.

Grizzly sells a 6", 3-jaw, true turn chuck with two piece jaws, plain back, semi-steel, for $330. I would easily purchase such a chuck. But, it won't fit on a G4000 lathe. Technically it would physically fit, but it would destroy the spindle and bearings, not to mention hit the ways when fully open. It's just too big. I would not want to go any larger than 4", 5" absolute maximum.

I am presently machining a new back plate for the Grizzly G4000 lathe. They come with an M39 X 4 thread, for their spindle. They are made of cast iron. All that needs to be done, is to machine it appropriately (major OD), true it up to the lathe and cut the boss, prior to mounting a chuck. Advise to those who have never machined a back plate, or one made of iron: Wear a suitable face mask. The iron dust produced during the machining process is easily ingested into the nose, lungs and throat.

Thorn3
04-21-2010, 03:37 PM
Toolguy: Thanks, although I apologize for being so long winded.

sansbury
04-21-2010, 10:37 PM
Speaking as one of the aforementioned cheap-#$@!#! 7x lathe owners, anything over $100 for a chuck is kinda-sorta real money to me. I have a 3- and 4-jaw, and am thinking about making an ER-32 chuck and standardizing around that. I figure if I machine the chuck myself on each machine, that's as good as is likely to be gotten.

Black_Moons
04-21-2010, 11:00 PM
Hi Black Moons

I want to thank you for the insight you share and I will definitely read it over again to digest it.

the "2 part" jaws you are talking about, is it the American standard tongue and groove design? If it's, that is what I have in mind about the 5" 6 jaw chuck.

and thanks again for pointing out the scroll's importance, I will pay close attention to that.

Yep, the tongue/groove design. Some good fasteners (hex head cap screws) stock would be nice too. China is famious for using some REALLY bad fasteners in places and this is one where the bolts will be reused/tightened many times. (Some chinese bolt heads are stamped offset (Not bad but ulgy), oversized (Causes hex keys to 'bind' and get stuck in the head, and eventualy strip the head), or just some serious defect in the threads/shaft (Broken screw... Good luck getting the remains out, could make the chuck usless without replacement parts)

Thorn3
04-22-2010, 03:08 AM
Black_Moons makes a very good point. I wanted to make the point myself, as I am sure many people would. My shop is located in my garage. With heating costs the way they are these days, I no longer heat my shop. I came out one morning and found several of the bolts clamping a part to the mill table snapped off. Something as simple as a change in temperature, caused the bolts to shear. It was at that moment, when I went on a crusade to change every import bolt in my machines. I went to the local hardware store with a long list of all of the bolts/screws/set screws needed. I purchased only grade 8 and grade 12. Never have I had a bolt shear since.

A chuck is a potential disaster waiting to happen. So are hold down clamps. They depend highly on the quality of the threaded hole and the bolts/screws holding everything together.

If the clamp bolts had sheared while I was machining the part, it could easily have thrown this part at me at high velocity, potentially causing serious harm. Any company, be they foreign or domestic simply cannot wimp out on the bolts and screws they use. To do so would be to create a serious hazard.

As it is now, I never use an imported tool, without changing all of the fasteners first. It is the only way to be sure. This should not be the mindset that machinists have to maintain. This mindset is so deeply embedded in me, that it came to life during the last Olympics, held in China. A young girl was suspended by a thin steel cable, high above the arena. I was at the edge of my seat, almost grinding my teeth in worry, that maybe the fasteners used to hold her up there, were of the same low quality that held my machines together when I first purchased them. People shouldn't have to think or feel that way.

Higher grade fasteners do cost more. But I am sure that anyone here would agree with me that they would be more than willing to pay the extra amount to insure their safety and the reliability of their machines/accessories.

Another issue to contemplate is the thread %. For those that don't know what thread % is, it is how deeply the threads extend into the material being tapped. The higher the thread %, the greater the contact surface between the threads on the fastener and the threads of the tapped hole. It can be compared to hanging from a ledge using only your finger tips, half of your finger length, or 75% of your finger length. Which is the most secure method of suspending your weight?

Depending on the material and the conditions of use, 50% and 75% threads are common. I tend to use 75% most. I have encountered thread percentages that appear to be less than 50%, as the threads simply rip out at low applied torque. If I encounter fasteners that fit extremely loose in a threaded hole, my first reaction is to re-tap the hole with a larger, higher percentage thread.

Along with this, is thread count. Metric threads use the distance between threads. M39 (39mm diameter) X 4mm (4mm between threads). Imperial threads use the amount of threads per inch. 10 (size 10 thread) - 32 (32 threads per inch). In either case, loading must be taken into account when choosing a fine thread or course thread. For fine adjustment applications with low loading, use a fine thread for greater accuracy or threading thinner materials. For high load applications, use a coarse thread.

Point being made, I agree with Black_Moons in his concerns regarding fasteners, threads and thread quality. Good quality fasteners are a relatively inexpensive path to safety and reliability. No good machine or tool should ignore this. Anything less, simply shows a lack of concern for the safety of machine tool users. Not a good image for any company to maintain.

Thorn3
04-22-2010, 03:49 AM
sansbury: My first lathe was a Grizzly 7 X 12 lathe. I did a lot of good work on that lathe. I still have it in fact, although it is now in parts, waiting to be integrated into other machines. The bed/ways are not hardened and ground, so they wore out with time and it was not worth fixing that problem due to the relatively low cost of the machine. It was my stepping stone, up to my 9 X 20.

I see no reason why a manufacturer or small job shop, can't make true turn chucks at a very reasonable price, for machines such as the 7 X 12.

It is well known that the majority of product ideas, come from people working in their own, small shops at home. Not from the major companies. So where does the majority of the market truly exist? With us! In fact, it is 'us' that give larger companies the reason to exist in the first place. So why shouldn't we be telling them what we want and need? They know the average home machinist cannot afford high end, production quality machines and tooling. We don't need it anyway. But often times, they need to be reminded of this.

Thorn3
04-22-2010, 05:19 AM
Joey: Any further thoughts on smaller true turn chucks?