# a way to make a cam



## yeorgjx (Feb 5, 2012)

I have used this way (2 times till now)...in cam making-(little cams).
I did not care about too much precision (these times) and I wanted to avoid the 4jaw independent chuck.
Do you think it is not a "safe" way ?
I know it is not the orthodox one...


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## steamer (Feb 5, 2012)

GJ

Nothing wrong with that way. Good for you for backing it up with a center.

A little more jaw engagement would be nice ....but it's working and it is backed up by the Tailstock Center.

It appears to be a plastic...like High Density Polypropylene....I don't know how that set up would work with steel, I would like to see a bigger chuck with deeper jaws.

But for plastic....

Dave


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## yeorgjx (Feb 5, 2012)

Thanks a lot Dave...
(The other cam I made was from soft iron (dia 14 mm, using a 3 mm srew).I tried to move the tool really easy and it worked...)


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## steamer (Feb 5, 2012)

Can't argue with success!


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## John S (Feb 5, 2012)

Often do this, in fact one job I do with an offset hole I keep a sample pattern with the packing piece taped to it so I have it for a quick setup.

John S.


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## n4zou (Feb 5, 2012)

Using a shim to offset the work in a three jaw chuck was common practice before CNC machines came around. There is a calculation for it that can be found at this link. http://www.myvirtualnetwork.com/mklotz/ unfortunately all his programs are written for DOS or (old) Windows operating systems. He provides source code so it's not too hard to convert them to JAVA or Pearl if you wanted to take the time to do that. Early in my working life I worked in a job shop. When we had a production run of parts that required an offset we would attach a machined soft jaw with the offset machined into it. The shops Tool and Die man would calculate and fabricate the soft jaw for that contract.


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## mygrizzly1022 (Feb 5, 2012)

HI  All

 I used that method when I made the cam for my tails stock lever lock. I used a penny, worked like a charm, as the penny took on a bend to match the stock it was holding.

Bert


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## n4zou (Feb 5, 2012)

Penny's make nice soft flat washers too.


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## yeorgjx (Feb 5, 2012)

Thanks Stevenson... I will prefer this way now on... much faster than to change chuck...

n4zou nice link...thanks...many usefull programs there.
After searching the Net,found the "dosbox v.074" program(http://www.dosbox.com/).This little program makes a window where inside you can run a dos program.
I followed the instructions and runned the cam program. 
The instructions I used is to mount the directory of the program (mine d:/progs/) writing "mount d: d:/progs/" and then wrote "cd cam" and then "cam" .
 OK  woohoo1
But I am not so familiar with inches ... 

P.S. (I like my american nickname "GJ")

GJ


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## steamer (Feb 5, 2012)

P.S. (I like my american nickname "GJ")

GJ




 :-[

Glad to hear that! Lots of typing the other way! :big: :bow:

Dave


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## mklotz (Feb 5, 2012)

n4zou  said:
			
		

> Using a shim to offset the work in a three jaw chuck was common practice before CNC machines came around. There is a calculation for it that can be found at this link. http://www.myvirtualnetwork.com/mklotz/ unfortunately all his programs are written for DOS or (old) Windows operating systems. He provides source code so it's not too hard to convert them to JAVA or Pearl if you wanted to take the time to do that. Early in my working life I worked in a job shop. When we had a production run of parts that required an offset we would attach a machined soft jaw with the offset machined into it. The shops Tool and Die man would calculate and fabricate the soft jaw for that contract.



DosBox

is a free program that will allow you to run all my programs, even the ones with graphics, on 64 bit systems.

I know it's been used for a long time but this single jaw packing method just seems a bit too insecure for my tastes. Included in the ECCENT archive, along with the single jaw packing computation, is a program to construct a much more secure way of "offseting" in the three jaw.

Basically, a split sleeve is constructed. It's ID matches the OD of the part so the part can slip into it. The split is wide enough so that a chuck jaw can fit through it to clamp directly on the part. Two jaws grasp the sleeve and one jaw grasps the part, producing an offset controlled by the sleeve thickness. The program calculates the required thickness based on the input required offset. Give it a try sometime.


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## yeorgjx (Feb 5, 2012)

mklotz you offer great programs there... Thanks for sharing...

Dave,for long names,in my country,we say "it is not a name...it is a train".Mine is not so big,here, but for you it is really "a lot of typing"...

GJ


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## steamer (Feb 5, 2012)

Rof}


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## bearcar1 (Feb 5, 2012)

Having the workpiece fully gripped/supported in a split carrier by all of the jaws of the chuck sure sounds a whole lot safer to me than what I see as a fine threaded bolt under one of the chuck jaws. Non-ferrous material or not, it just doesn't give me a warm (cold?) sense of security. However, thank-you GJ, (yes that is a whole lot easier to pronounce) for pointing out the DosBox shell prg. for us MAC users. 

BC1
Jim


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## n4zou (Feb 5, 2012)

mklotz  said:
			
		

> DosBox
> 
> is a free program that will allow you to run all my programs, even the ones with graphics, on 64 bit systems.
> 
> ...


You can install DOSBOX in Ubuntu and other Linux distributions but it no longer operates properly. It will not function with drives formatted in any other format than FAT. I use NTFS so it's impossible to create the required FAT dependent directory where the old programs would be filed. WINE also operates this way so it fails as well. GCC comes with all Linux distributions so it's free but I prefer using JAVA whenever it's appropriate because the user can run the program directly from the website eliminating the need to download and set up the program on their computer and the program operates on any computer that can access the Internet. Very soon everyone will be using Tablet's connected to their local wireless network and/or the Internet eliminating storing anything on a Lap Top or Desk Top computer and it's storage device.


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## mklotz (Feb 5, 2012)

n4zou  said:
			
		

> ... It will not function with drives formatted in any other format than FAT. I use NTFS so it's impossible to create the required FAT dependent directory where the old programs would be filed. ...



Is that peculiar to Linux?

I ask because I have it installed on my NTFS drive running under WinXP and it operates exactly as advertised.


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## mklotz (Feb 5, 2012)

bearcar1  said:
			
		

> Having the workpiece fully gripped/supported in a split carrier by all of the jaws of the chuck sure sounds a whole lot safer to me than what I see as a fine threaded bolt under one of the chuck jaws. Non-ferrous material or not, it just doesn't give me a warm (cold?) sense of security.



There are other problems with the jaw packing approach. To get an accurate offset one needs to know the jaw width at the tip precisely and this is very difficult to measure accurately.

Obviously, any of these 3jaw kludges are, well, kludges. The right way is to use a 4jaw. However, the split tube is a lot more secure if you must kludge.

Once, just once, in my career I set up a job with packing in the 3jaw. Before I turned the lathe on I stared at it and thought to myself, "Not with me in the room!".


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## Foozer (Feb 5, 2012)

n4zou  said:
			
		

> You can install DOSBOX in Ubuntu and other Linux distributions but it no longer operates properly. It will not function with drives formatted in any other format than FAT. I use NTFS so it's impossible to create the required FAT dependent directory where the old programs would be filed.



I'm confused, easily done 

I use DosBox under Ubuntu 10.4 and it works just fine. Not a dual boot system. Ran Marv's Eccent program with .125, 1.125 and .25 as the variables with 0.3557 as the result. Ran the same numbers on the Windoze XP box NTFS and got the same answer.

DosBox works for me and still is my first choice for running Marv's programs under Linux (Ubuntu here)

Robert


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## Groomengineering (Feb 5, 2012)

n4zou  said:
			
		

> You can install DOSBOX in Ubuntu and other Linux distributions but it no longer operates properly. It will not function with drives formatted in any other format than FAT. I use NTFS so it's impossible to create the required FAT dependent directory where the old programs would be filed. WINE also operates this way so it fails as well. GCC comes with all Linux distributions so it's free but I prefer using JAVA whenever it's appropriate because the user can run the program directly from the website eliminating the need to download and set up the program on their computer and the program operates on any computer that can access the Internet. Very soon everyone will be using Tablet's connected to their local wireless network and/or the Internet eliminating storing anything on a Lap Top or Desk Top computer and it's storage device.



Hi n4.

First off no offense but why would you use NTFS under Linux? Ext3 or 4 are much more efficient file systems.

As to mounting in DOSBox it seems tricky but it's not, i.e. "mount c ~/Documents/Shop/Programs" will mount the FAT equivalent of c:/(user)/Home/Documents/Shop/Programs.

Just tried it under Ubuntu 11.10 x64 and it works fine.

Hmmm.... Now that I've installed DOSBox I guess I need to raid Marvs website! ;D :bow:

Cheers

Jeff


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## ncollar (Feb 15, 2012)

G J
I've used a three jaw to chuck up a piece of square stock. If it works do it. When it comes to safety no it is not the best thing to do. But as long as the cuts are light and not running very fast. I think it a good share. Thank you.
Nelson Collar ???


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