3 jaw chuck soft jaws

[GeneT45]

If you want "top accuracy" a 4-jaw, a good indicator, and some patience is the ticket. 3-jaws are great, particularly when the root stock doesn't matter, but 4-jaws are king. If you can't center stuff up in a 4-jawl, you can't machine...

GsT

 

[Karl_T]

Yep, more than one way to skin this cat. A good machinist should master both methods so a choice can be made on any particular job.

 

[Jimsehr]

Yep, more than one way to skin this cat. A good machinist should master both methods so a choice can be made on any particular job.

My way is to bore an emergency 5c collet. It’s guick easy runs true and concentric.
Most of my emergency collets cost me less than 10 bucks and can be saved as bored or bored for another size part later.

 

[Jimsehr]

The problem with most scroll chucks is that the “scroll” isn’t consistent over the entire length of travel. You might have .001” at one point and .003” at another If you intend to primarily use the chuck at the diameter you bored the soft jaws you should get consistent results.

However that’s no guarantee you won’t significant runout at other diameters. Soft jaws are primarily used when making multiples of the same part, or in situations where you’re using soft materials and it’s important not not to mar the surface.

I made a set of chuck jaws that take collet pads. The pads only take a couple minutes to change. They all locate same spot on scroll so they run true.
The pads also hold square and hex stock. Also have emergency pads ready to bore to any size needed and these can be bored to depth of a part like a washer.
The pads I am using came from a #3 W&S turret lathe.
Jim Sehr
I made them for my 11 inch Logan lathe.

The problem with most scroll chucks is that the “scroll” isn’t consistent over the entire length of travel. You might have .001” at one point and .003” at another If you intend to primarily use the chuck at the diameter you bored the soft jaws you should get consistent results.

However that’s no guarantee you won’t significant runout at other diameters. Soft jaws are primarily used when making multiples of the same part, or in situations where you’re using soft materials and it’s important not not to mar the surface.

 

[Karl_T]

maybe I been sleeping under a rock... What's a collet pad?

<EDIT> answered my own question. they are on ebay

LOT OF COLLET PADS BOTH SMOOTH AND SERRATED VARIOUS SIZES INCOMPLETE SETS | eBay

Thread Gages. TOOLING LOT. LOCATION: WB2-1-7-3. PRODUCT SPECIFICATIONS AND / OR LABELING ”Gage was protected very good. Will buy from you again.”. Fast & Secure. We pride ourselves in prompt and accurate service to make sure your order arrives when you need it to.

www.ebay.com

 

[Jimsehr]

maybe I been sleeping under a rock... What's a collet pad?

<EDIT> answered my own question. they are on ebay

LOT OF COLLET PADS BOTH SMOOTH AND SERRATED VARIOUS SIZES INCOMPLETE SETS | eBay

Thread Gages. TOOLING LOT. LOCATION: WB2-1-7-3. PRODUCT SPECIFICATIONS AND / OR LABELING ”Gage was protected very good. Will buy from you again.”. Fast & Secure. We pride ourselves in prompt and accurate service to make sure your order arrives when you need it to.

www.ebay.com

Hardinge also sells them but pricy.

 

[bill stupak]

f you want "top accuracy" a 4-jaw, a good indicator, and some patience is the ticket. 3-jaws are great, particularly when the root stock doesn't matter, but 4-jaws are king. If you can't center stuff up in a 4-jawl, you can't machine...

GsT

Totally agree, actually have a 4 jaw on my 12" lathe right now boring a hole in rectangular stock. This was mainly a project to see if I could do it and add another option for the tool box

 

[Jimsehr]

Four jaws are fine but if you are running a thousand parts I always will go for a collet.