Skand 6" Chuck Questions

[Joe Pitz]

Hello All, lots of questions, going through new Clausing 6300 lathe. More newbie questions.

The chuck I have, is a three jaw 6" chuck, Skand Chuckfabriks AB, 294142. When you look at the below image the thee jaws have bolt holes but are pretty much flush against the chuck face.

How difficult is it to locate chuck jaws for such a chuck? Is there a way to locate full chuck jaws both inside and outside mounts? Do you have to choose jaws from the same manufacture? Are bolt on jaws as accurate as full chuck jaws?

Also included is an image of the backing plate to the chuck. I have a 5C collet system on my lathe so the backing plate fits the 5C collet system.

Does anyone know what type of backing plate this is?

Thanks
Joe

 

[hvontres]

Those look like American Standard Tounge and Groove jaws. To be sure , measure the width of the tounge and the slot in the center. The tounge should be 3/8" wide and the slot 1/2". If so, Monster Jaws sells steel soft jaws for about $40(http://monsterjaws.com/6-steel-american-standard-tongue-groove-jaws-pointed-2-0-ht/), but you would have to turn steps into them to act like a standard set of jaws.

A set of hardened jaws will set you back about $140-$200 at Enco, but you will want to double check the dimensions with them, since they don't seem to be listed in their catalog.

The backing plate looks like a custom job with a 5C shank on it. The Spindle on the 6300 is a L00 Taper. It is underneath the protective sleeve behind the collet adapter. You can find L00 tooling on Ebay for ~300 if you are patient.

 

[hvontres]

Those look like American Standard Tounge and Groove jaws. To be sure , measure the width of the tounge and the slot in the center. The tounge should be 3/8" wide and the slot 1/2". If so, Monster Jaws sells steel soft jaws for about $40(http://monsterjaws.com/6-steel-american-standard-tongue-groove-jaws-pointed-2-0-ht/), but you would have to turn steps into them to act like a standard set of jaws.

A set of hardened jaws will set you back about $140-$200 at Enco, but you will want to double check the dimensions with them, since they don't seem to be listed in their catalog.

The backing plate looks like a custom job with a 5C shank on it. The Spindle on the 6300 is a L00 Taper. It is underneath the protective sleeve behind the collet adapter. You can find L00 tooling on Ebay for ~300 if you are patient.

Oh, and if you do decide to get the hardened jaws, keep in mind that you will need to re-grind them to match up with the existing master jaws.

I just cheked my stash, and I have a set of 6" steel soft jaws, but they don't have the angles on the front. Let me know if you are interested.

 

[kd4gij]

Shars has chuck jaws also. And as hvontres said thay will need to be ground. All sorts of make shift tool post grinders on here just do a serch. You can use a Dremel, die grinder, rotozip, trim router. just to name a few.

 

[Joe Pitz]

Ok, thanks everyone, Henry when you say the jaws need to be ground to fit, "they do not have the angles on the front" are you referring to the steps? Then you say "you will need to re-grind them to match up with the existing master jaws." What do you mean by that? Do you mean that I would have to mill the tongue and slot?

Can that be milled or will I need to grind as they are hardened?

Also if you purchase soft jaws and grind, can you then heat treat and temper?

Sorry I am a total newbie I am learning most everything from scratch, many years ago I use to program cnc machines,

And did a bit of manual machining. But I am very green.

kd4gij indicated to use a make shift tool grinder, would that be to create the steps?


Thanks

 

[Joe Pitz]

I went out and measured the tongue, it is .321, the slot is close to .500. I checked the specs on the Monster Jaws the slot for the tongue is .500 and the groove slot is .313. The distance between holes is 1.5, which is the same on my chuck.
Shars has the same jaws for $24.54.

Might be close enough with a bit of tweeking.

Thanks

Joe

 

[wa5cab]

Normally, when someone refers to grinding or re-grinding jaws on a 3-jaw chuck, they are referring to the clamping surfaces, not to turning rectangular steel soft jaws into standard stepped ones. Most threads discussing grinding chuck jaws will be about correcting bell mouth (a condition where the main clamping surface through wear or other damage is no longer parallel to the machine axis) or wear. But the technique is the same as you would use on replacement jaws.

 

[hvontres]

Most of the soft jaws I have seen have some 120 degree chamfers milled on the front to allow the jaws to come close together in the center. I have a set that only has the tounge and groove as well as the bolt holes machined.
I originally got them for my 8" chuck, but it turns out they are actually 6" Jaws. If you are interested, I can set them up and mill off the corners for you. You would still need to decide how big you want to cut the steps.

For now, you can use your existing chuck for smaller stock by just clamping it in the Master Jaws (the ones still mounted in the chuck), or if you have the right size collet, that would probably be even better.

 

[Silverbullet]

You might be able to find a back plate with the loo mount and remount the chuck to it. Not sure if I'd want to use it in the 5 c mode it's likely to cause some damage to The lathe if you make some heavy cuts or run a heavy piece most 5 c chucks are about the 4" size . There must be a reason? Think the mount you have was homemade because they didn't have a back plate. Just looks a bit unsafe to me even a six inch chuck is heavy if it torques loose or metal fatigue who knows what can happen.

 

[Joe Pitz]

Thanks Silverbullet,

Is it then common to switch between L00 and the 5C collet system. I like the idea to use the 5C for stock up to 1" and then for larger jobs switch to the L00 backing plate. Would that be hard to switch back and forth?

Is there some book that goes into details about how the backplates and different systems around work and what is available for the lathes. Since being a newbie, this is all very new to me. Normally when picking up new technology I locate the technical material and learn from that. But I have a feeling that this old technology is learn through experience.

Thanks

Joe