Carriage Stop Ring, & Blade "Zero"

[dusty]

Oh but there is debate. Other than this comment, I shall remain silent in the debate but I disagree on "inadequate". Inadequacy is a function of expectancy.

[JPG]

Oh but there is debate. Other than this comment, I shall remain silent in the debate but I disagree on "inadequate". Inadequacy is a function of expectancy.

Where in the SS literature is it referred to as a bumper/cushion/shockabsorber?

Only those who have unwarranted expectations will debate it's inadequacy for that function.

[Sazerac81]

The PVC carriage ring worked very, very well! It allows very nice and repeatable placement of the blade within the ZCI I have. No fuss and no muss, just press the carriage firmly against the rings and one is all set!

Thanks for the idea JPG!

Cheers,
John

[dusty]

May you never have a reason to cuss him because of the idea. Do not allow the headstock (or carriage) slide downward on the Way Tubes when you go vertical with either one of both unlocked. The PVC Spacer is a bit more of an impact point than was the rubber ring.

If you have the ring sized the way you want it, the location of the blade within the table cutout will be much more predictable.

I would like to see a rubber bumper strip designed to fit across the headstock and a pair of adjustable stop collars to fit on the Way Tubes. That would provide for both a soft landing and adjustablility.

[BuckeyeDennis]

If you're serious about preventing damage when something as heavy as a headstock slide-hammers a structure, you need something like the hydraulic shock absorber below.

I've used them as part of an upgrade package for cam-operated machine tools, with spring-return tool slides. If a slide sticks while the cam retracts, and then lets loose, you have a heavy return spring accelerating a roughly 100-lb tool slide at about 1 g. When it impacts, it bends or breaks OEM parts. But with one of these shock absorbers installed, all that kinetic energy is harmlessly turned into heat in the shock absorber. It doesn't even make a thud.

The energy-absorption requirement for a Shopsmith is roughly 50 lb. x 3 ft, or 150 ft-lb. The shock absorber below has a stroke of 1/2", and thus it must apply a stopping force of at least 200 / (0.5 /12) = 4800 lb to absorb that much energy. So you'd better have a sturdy mount for it. This also illustrates why something with limited compressibility, such the standard SS stop rings, will generate an even larger impact force.

IMG_0750.PNG (306.87 KiB) Viewed 6769 times

EDIT: Whoops, I just notifed that the shock absorber shown above is rated for 200 inch-pounds, not 200 foot-pounds. So a considerably larger one is needed, at about 3x the cost. I thought that one was mighty inexpensive.

[JPG]

If you forget to lock the headstock(or carriage) prior to raising to vertical, there is only one individual that deserves cussing at. Look in the mirror.!

I recall the demo a half century ago when the demonstrator stated 'you will forget to lock only once'.

He was half right. After that once it was several decades later until the second time. However not as shocking as it was immediately recognized and 'subdued'(likely a direct result of age related slowness of the raising effort).

[dusty]

Yes, it is an individual thing like most other mishaps in life. A little thought and attention to detail would truly prevent such a mishap. Unfortunately, that is not always the way it works out. Yup, I must be a slow learner. I have lifted or attempted to lift to vertical more than once when not everything was locked. Lucky for me, I still have no cracked castings.

The way I use the equipment now, I could possibly never do it again. The Shorty is set up to be my drill press. With this change, the propensity for this particular mishap is minimized.

Hopefully no one on this forum will have an occasion to report otherwise.

Sothen with this discussion coming to a close as it is, I suppose there are some who will say that the rubber bumper was never a shock absorbor and thusly leaves its function to be "a spacer"between the headstock and the carriage. Just a hard rubber spacer.

BTW, don't try to trim it. That is some tough rubber.

[reible]

Just a couple of thoughts on the forgetting to lock front.

One is that with the lift assist I found it goes to vertical pretty fast and takes more effort to go back down so it would be harder to control a slipping headstock if it started to happen.

Two is that with the dual lift mode it would be possible to have the headstock slide to the "other" end. The distance would likely be smaller but it could still happen.

The last note is that the new powerpro adds weight to the headstock, forgot the amount but 20 some pounds comes to mind. More potential for damage one would think.

Ed

[Sazerac81]

Just a couple of thoughts on the forgetting to lock front.

One is that with the lift assist I found it goes to vertical pretty fast and takes more effort to go back down so it would be harder to control a slipping headstock if it started to happen.

Two is that with the dual lift mode it would be possible to have the headstock slide to the "other" end. The distance would likely be smaller but it could still happen.

The last note is that the new powerpro adds weight to the headstock, forgot the amount but 20 some pounds comes to mind. More potential for damage one would think.

Ed

I have definitely forgotten to lock, but fortunately caught in time when I saw the headstock begin to move before I was even close to being vertical.

I am very OCD about locking everything up now, but definitely can get distracted when there are a lot of moving parts so I have taken the time to do the 5 point check every time I make a change to make sure everything is on the up and up.

I am very happy with the PVC rings and to be honest per my opinion, the rubber ring isn't going to do diddly squat if you are in full vertical compared to the dual PVC rings I have on there now if the the headstock decides to slip for some reason. At that point, you've got more to worry about like the bit or object you've got locked into the headstock (like the drill bits/router bits) getting destroyed as well as your very expensive main table.

Cheers,
John

[bigmoguls]

I would appreciate any advice here. My stop ring appears to be incorrectly sized to place the blade in the center of the table insert opening. When I push the carriage up against the carriage stop ring, the blade position is to the right of the table insert opening, the stop ring appears to be too wide.

What am I missing?

My system is a Mark V model 510 from the early 90's.