Shopsmith Forums

Okay......I received the new Center Adjustment Ring, purchased the tap and drill needed, and most important, finally found the time to start working on the additional set screw.
One of the things that I noticed right off was that the wall thickness on the new adjustment ring was different! I decided to take out my calipers and measure both the old and new rings. The old ring was 2.84mm, and the new ring was 4.78mm! Definitely, a needed improvement!
Because of the information supplied by Ed,:) I was able to drill and tap the tailstock in a relative short period of time. Thanks again Ed!!
I still had to make a pencil mark on the Center Adjustment Ring for an exact point to point match up.
Having two set screws on the tailstock does make a positive difference!:D


John
FlashbacPT

Be kind now as I am not a turner but I do have a question.

If everyone is using a live center, where does the force come from that tends to turn the Eccentric Mount (501437) after it has been installed, adjusted and the set screw tightened?

Is it from a live center that is binding?

I pulled the Eccentric Mount on mine and it is obvious that I don't turn. There is one, rather deep ring where the set screw contacts. There is no sign that the Eccentric Mount has attempted to relocate. What I pulled it for though was to see what sort of set screw is there. It is a
5/16"-18x3/8" Black Oxide Alloy Steel Knurled Cup Point Socket Set Screw.

dusty wrote:Be kind now as I am not a turner but I do have a question.

If everyone is using a live center, where does the force come from that tends to turn the Eccentric Mount (501437) after it has been installed, adjusted and the set screw tightened?

Is it from a live center that is binding?

I pulled the Eccentric Mount on mine and it is obvious that I don't turn. There is one, rather deep ring where the set screw contacts. There is no sign that the Eccentric Mount has attempted to relocate. What I pulled it for though was to see what sort of set screw is there. It is a
5/16"-18x3/8" Black Oxide Alloy Steel Knurled Cup Point Socket Set Screw.

I do not think the 'problem' is caused by torque from the center, but rather a combination of repeated and overly aggressive adjustment and tightening of the single screw. The ones I have are a bit sloppy fit into the actual tailstock casting which leads to drifting. With a single set screw, an over the center condition exists. A second set screw eliminates that.

JPG40504 wrote:I do not think the 'problem' is caused by torque from the center, but rather a combination of repeated and overly aggressive adjustment and tightening of the single screw. The ones I have are a bit sloppy fit into the actual tailstock casting which leads to drifting. With a single set screw, an over the center condition exists. A second set screw eliminates that.

If that be the case, putting in a second set screw simply doubles the speed at which the Eccentric will be damaged. Take the allen wrench away from the gorilla.

dusty wrote:If that be the case, pitting in a second set screw simply doubles the speed at which the Eccentric will be damaged. Take the allen wrench away from the gorilla.

I have a supposition (ok, more of a wild guess). I suspect the real cause of the the pitting in the eccentric is the way people try to remove the live or dead center after finishing a turning session.

I know that my centers get good and stuck after a turning session. To remove them I know I am supposed to take the tail stock off, support the eccentric fully and tap out the center.

I also know that I usually am too lazy and may either apply a twisting torque to the center to try to loosen it from the eccentric and I have on occasion tapped the center (lightly) without carefully supporting the eccentric. I suspect both practices will, over time, cause the set screw to gouge the eccentric. This may in turn cause one to try to over tighten the set screw to get a better grip in the gouged eccentric.

I have no evidence or data to support my supposition. However, I believe from now on I will take the precaution of removing a stuck center by loosening the set screw on the eccentric, pulling out the center (with the eccentric still attached), and then fully supporting the eccentric before tapping out the center.

Al

algale wrote:I have a supposition (ok, more of a wild guess). I suspect the real cause of the the pitting in the eccentric is the way people try to remove the live or dead center after finishing a turning session.

I know that my centers get good and stuck after a turning session. To remove them I know I am supposed to take the tail stock off, support the eccentric fully and tap out the center.

I also know that I usually am too lazy and may either apply a twisting torque to the center to try to loosen it from the eccentric and I have on occasion tapped the center (lightly) without carefully supporting the eccentric. I suspect both practices will, over time, cause the set screw to gouge the eccentric. This may in turn cause one to try to over tighten the set screw to get a better grip in the gouged eccentric.

I have no evidence or data to support my supposition. However, I believe from now on I will take the precaution of removing a stuck center by loosening the set screw on the eccentric, pulling out the center (with the eccentric still attached), and then fully supporting the eccentric before tapping out the center.

Al

Hmmm. Sounds like a good reason to drill a through hole in the work bench. A hole just big enough for the live center to go through.

Just a couple thoughts and a observation......

Al,
You raised a good point about removing stuck centers, and I feel this would be a good habit to get into.

Dusty,
A couple of things...... First, the damage that was on my Center Adjustment ring was on the "upside" from the set screw, not the angle from which damage could occur from taking a mallet to knock out a stuck center. You just may have a valid point that the damage occurred during the turning process, created by the force that occurs when initially turning a piece of wood to round. When a piece of wood, especially large pieces, are set up initially to turn, the wood is out of balance, and can/does create a lot of force that could be applied to the set screw on the "upside" from the set screw. Even though you counter this by turning at a very slow speed, the first cuts can be very hard, causing even more pressure on the set screw and Center Adjustment Ring.
Being that I purchased my ShopSmith in 1981, I will chalk the damage up to normal wear and tear that has occurred over the years of turning, etc.

John
FlashbacPT

dusty wrote:If that be the case, putting in a second set screw simply doubles the speed at which the Eccentric will be damaged. Take the allen wrench away from the gorilla.

The second set screw eliminates the single 'pinch point' and reduces the need for the gorilla act.

The eccentric is sloppy in the tailstock hole and a single set screw must be very secure to prevent that slop from causing the eccentric moving. With a second screw, the slop is essentially eliminated(three contact points[screw,screw,point opposite & midway between the screws]). The set screws need not be as securely tightened.

It's purpose in life is to prevent rotation of the eccentric under load while allowing adjustment to offset the center..

Boy I guess we all have our reasons for adding a second set-screw.

I have never experienced any rotational forces on the tail stock.

I do not pound out centers while the tail stock is mounted.

What I have experienced is difficulty adjusting the tail stock due to having had a set-screw just a smidgen off from where I now want to lock it. As you tighten it slides back to the old indent....

This happens at zero point most often as doing off sets for me is done less often.

I'm not sure how much better the second set-screw is long term but it has helped me in the short term.

It could be the newer dual tilt method will make for less adjustments due to the redesign??? That would be nice.

So that is my story and I'm sticking to it.

Ed

reible wrote:Boy I guess we all have our reasons for adding a second set-screw.

I have never experienced any rotational forces on the tail stock.

I do not pound out centers while the tail stock is mounted.

What I have experienced is difficulty adjusting the tail stock due to having had a set-screw just a smidgen off from where I now want to lock it. As you tighten it slides back to the old indent....

This happens at zero point most often as doing off sets for me is done less often.

I'm not sure how much better the second set-screw is long term but it has helped me in the short term.

It could be the newer dual tilt method will make for less adjustments due to the redesign??? That would be nice.

So that is my story and I'm sticking to it.

Ed

Either you are not a 'gorilla' or have a newer(thicker) eccentric.

It is the problem you describe(returning to previously dug hole) that leads to gorilla tactics and caved in surface.

I believe that two setscrews with flat point would be an improvement.

My comment re rotation was not meant to imply that they are prone to rotating under load, but that they are there to allow repositioning and to be secured at that setting(as opposed to being free to rotate without them).

With a single set screw, the result is two point contact from opposite directions. Some side play is still possible, which a three point contact eliminates.