Aloris tool post T-nut

[dgfoster]

Yes, that is so. However... With the top of the compound in good contact, a good fit on the t-nut and 4 or 5" of steel on top it isn't likely to flex much. Doesn't take a lot though if you're pushing the machine a bit.. I would not as the relief unless necessary, but that's just me.

I will submit that it is true that the tool post will cinch up if the compound is flat and the tool post is flat. But it cinches up more easily and more securely if centrally relieved.

I’ll grant you that the relatively tall column of the tool post probably does not deflect that much though steel is simply rubber in disguise. However the top of the compound is not nearly so thick and is also made of rubber—-cast iron rubber, but elastic material nevertheless. If you consider how the top and to a lesser extent the tool post, being elastic, have to deflect under load, getting the load bearing points distributed radially improves their ability to resist rotation substantially. I have tested this out in practice and will submit the difference is significant. I also know of one other case where a friend followed this advice and found a big difference. The amount of torque needed to cinch up the post reliably was about 1/3 that of an unrelieved post.

There is room for both opinions as there should be. Just trying to flesh out the reasoning behind my suggestion.

FWIW,
Denis

 

[richard newman]

Relieving the center of the toolpost base decreases the area of contact. For any given torque on the center bolt, that will give more pressure on the contact surface, maybe that is significant. Plus the pressure is at the perimeter of the contact face, that has to help a lot.

One could test this with two sheet metal shims, one with an large hole to duplicate the effect of relieving the center.

 

[Joe Gwinn]

One could test this with two sheet metal shims, one with an large hole to duplicate the effect of relieving the center.

Or one sheet steel shim, with the thickness reduced only in the central region, so it will center and stay centered.

 

[eKretz]

I will submit that it is true that the tool post will cinch up if the compound is flat and the tool post is flat. But it cinches up more easily and more securely if centrally relieved.

I’ll grant you that the relatively tall column of the tool post probably does not deflect that much though steel is simply rubber in disguise. However the top of the compound is not nearly so thick and is also made of rubber—-cast iron rubber, but elastic material nevertheless. If you consider how the top and to a lesser extent the tool post, being elastic, have to deflect under load, getting the load bearing points distributed radially improves their ability to resist rotation substantially. I have tested this out in practice and will submit the difference is significant. I also know of one other case where a friend followed this advice and found a big difference. The amount of torque needed to cinch up the post reliably was about 1/3 that of an unrelieved post.

There is room for both opinions as there should be. Just trying to flesh out the reasoning behind my suggestion.

FWIW,
Denis

I'm not arguing the point, like I mentioned earlier - what you say is true. Whether the toolpost *needs* to be machined is another matter. If he's running a fairly small lathe with rinky-dink DOC and feed rate it likely isn't necessary. If the lathe is a heavy stout machine that can take a serious cut it might be of benefit.

I almost wonder why they don't do that straight from the factory. Even a very slight concavity would do it.

 

[Shaun5]

From all the posts (negative and positive), I identified (before posting) the general consensus of the problem...

I posted the issue for two reasons (before modifying new parts): 1) I was not expecting to have any issues with new products of this caliber, so I assumed I was doing something wrong (ie not torquing the nut to a high enough value) or just expecting too much (my ultimate fear after spending so much). 2) My YouTube search for a solution yielded a couple of multifix tool videos stating the importance of the T-nut sitting flush with the compound (doesn’t seem what is expected on non multifix tool holders).

The stud stops ~1/8” before the bottom of the T-nut, so my compound is safe. The finish on the T-nut is less than impressive, so if I find a suitable drop, I’ll make a new one.

I guess rinky-dink is all relevant (my lathe is a Kingston HJ-1100 with a CA size tool holder).

I appreciate all the input and will report back when I feel like I have the rigidity I was expecting.

 

[eKretz]

A rinky dink cut has a lot more to do with cutting speed, DOC and feedrate than the name on or even size of the lathe or toolpost... My comment had nothing to do with the machine itself, rather, how it is being used.

 

[thermite]

From all the posts (negative and positive), I identified (before posting) the general consensus of the problem...

I posted the issue for two reasons (before modifying new parts): 1) I was not expecting to have any issues with new products of this caliber, so I assumed I was doing something wrong (ie not torquing the nut to a high enough value) or just expecting too much (my ultimate fear after spending so much).

The machine - and the tooling - were made and fitted by humans you've never met. They are not necessarily even as attentive as YOU are. So don't assume just because something has a company "name brand" on it - or cost a large sum - that you are the one as has gone blind and numb-fingered. If it looks, acts, and feels wrong, it IS wrong.

Trust your senses. Measure. Identify the problem yourself. Correct it yourself.
Go put it to doing useful work. Check it again. "Tune" it even better.

Problem-solving is the game. Confidence in yourself to be able to DO that is bedrock. Nurture that. It pays-off very nicely.

Nothing else is faster. Few alternatives are as cheap.

I guess rinky-dink is all relevant (my lathe is a Kingston HJ-1100 with a CA size tool holder).

Nothing "rinky dink" about that one 2,000 lbs of good Iron in the right places wouldn't improve (it's actually lighter than a much smaller 10EE, about the same mass and HP as an also-smaller 14" x 30" Cazeneuve HBX-360!):

17" x 43" New Kingston Lathe Model HJ-1100 for sale at Worldwide

Even so, ... basic workmanlike "medium", 7+ HP, decent through-bore, 4 MT TS? Reasonable value-for-money.

Earn some coin with it, you can trade-up to a vintage Craven Brothers, later!

Craven 5000x15000 - YouTube

 

[EPAIII]

"Sanctified" brand?????

If it doesn't work, it is not sanctified. No brand, no matter how well respected it may be, is always perfect. I remember a saying from the old Davy Crockett TV series, "Be sure you're right, then go ahead!" In other words, if it is broken, FIX IT.

I’ve posted about this several times in the past. Besides the good advice concerning tee nut height in a few of the posts above, the contour of the base of the tool post itself makes a difference in how solidly it locks down to the compound.

https://www.practicalmachinist.com/...ee-nut-fit-lathe-compound-291143/#post2376382

Since you are dealing with a nearly “sanctified” brand of tool post, you may be reluctant to alter it from its brand new “perfect” state to make it better. Too bad.

Denis

 

[thermite]

"Sanctified" brand?????

If it doesn't work, it is not sanctified. No brand, no matter how well respected it may be, is always perfect. I remember a saying from the old Davy Crockett TV series, "Be sure you're right, then go ahead!" In other words, if it is broken, FIX IT.

Going by where I was living at the time.. around 40 years ago.. a guy in Fairfax County, VA took delivery of a brand-new Rolls-Royce. It had a 'sag' in the paint. Rear roof pillar, IIRC the newspaper photos. He raised a fuss. They tried to fix the paint. MANY times. Failed to do.

He took Drools-Royce into County COURT.. and PROVED that ever single Chevy on a fair-sized local dealer's entire lot had BETTER paint, and on every inch it covered, not just partial.

Brits might chuckle. They EXPORT Rolls, not KEEP them.

Same as the Scots and John Walker Distillers. Brand origin in a common grocery store!

A Scot won't touch their swill.

Johhny Walker only gets labeled as "Scotch Whisky" to take enduring bloody revenge on the Sassenach.. and keep them off the "good stuff"... which is meant for the Scots, of course!

 

[richard newman]

My YouTube search for a solution yielded a couple of multifix tool videos stating the importance of the T-nut sitting flush with the compound

Interesting Shaun, can you post links to any of those videos, wondering why they state that?

That Kingston looks like a nice lathe to me, just the size I could use.

 

[Shaun5]

Interesting Shaun, can you post links to any of those videos, wondering why they state that?

That Kingston looks like a nice lathe to me, just the size I could use.

https://youtu.be/FDPfB4r1qEw

https://youtu.be/4NKDlcb_Ysk

 

[Scottl]

It sounds as if a bearing or other top part is missing. Normally the nut will secure the tool post body yet still allow free movement of the lever. If there is any interaction between the two it is not working as designed.

It also could be assembled wrong.

 

[Mike1974]

This might sound stupid, but just take it apart and make it work... For better or worse. Check the nut, stud, compound, flatness, burrs, u name it. I mention because years ago had a finish od tool on a cnc lathe leaving a tit. Inspected everything I could think of, couldn't figure it out. Finally just shimmed the stupid thing and problem solved

 

[EPAIII]

Why they don't do that at the factory? Remember that the error in a lathe cross slide is or at least should always be in favor of a concave facing cut as opposed to a convex one. So, if the base of the tool post was faced in a lathe, it probably is slightly concave.

I'm not arguing the point, like I mentioned earlier - what you say is true. Whether the toolpost *needs* to be machined is another matter. If he's running a fairly small lathe with rinky-dink DOC and feed rate it likely isn't necessary. If the lathe is a heavy stout machine that can take a serious cut it might be of benefit.

I almost wonder why they don't do that straight from the factory. Even a very slight concavity would do it.

 

[EPAIII]

As for the top of the tee nut sitting flush with the top of the compound, I see no reason for stating it that way. Trying to make it flush or even will have a high risk of the nut being tightened against the tool post and neither of them being that tight against the compound.

Remember the old axiom that all the parts of a machine are made of rubber. If a rubber tee nut is compressed from the tension from the central stud, then it will bear on the bottom of the tool post, probably at the expense of contact between the compound and both of those parts.

I do not care what anyone says, I said it before and I will say it again, the top of the tee nut should be BELOW the top of the compound. That guarantees a proper fit. PERIOD!

From all the posts (negative and positive), I identified (before posting) the general consensus of the problem...

I posted the issue for two reasons (before modifying new parts): 1) I was not expecting to have any issues with new products of this caliber, so I assumed I was doing something wrong (ie not torquing the nut to a high enough value) or just expecting too much (my ultimate fear after spending so much). 2) My YouTube search for a solution yielded a couple of multifix tool videos stating the importance of the T-nut sitting flush with the compound (doesn’t seem what is expected on non multifix tool holders).

The stud stops ~1/8” before the bottom of the T-nut, so my compound is safe. The finish on the T-nut is less than impressive, so if I find a suitable drop, I’ll make a new one.

I guess rinky-dink is all relevant (my lathe is a Kingston HJ-1100 with a CA size tool holder).

I appreciate all the input and will report back when I feel like I have the rigidity I was expecting.

 

[thermite]

I do not care what anyone says, I said it before and I will say it again, the top of the tee nut should be BELOW the top of the compound. That guarantees a proper fit. PERIOD!

LOL! Where I HAVE tee slots (10EE's), I have to agree. In spades.

But there are exceptions to every rule. And then you have the French.

Cazeneuve mounted/still mounts a 4-Way ELSE a Multifix on the older HBX-360 or its "teach in" hybrid manual/CNC current "Optica" version.

No Tee slot? No Tee nut needed!

The pragmatists sidestep the whole dam' issue by using a solid ground steel plate. FULL bearing of the bottom of a(ny) TP thereby assured.

And one can swap the plates, thickness as appropriate to the TP.

What's not to like about that?

 

[EPAIII]

A tally count of internet videos does not make something correct. I can refer you to recent events.

 

[thermite]

A tally count of internet videos does not make something correct. I can refer you to recent events.

That's a tad "vague?

You speaking of spun QCTP's?
The price of eggs after that recent tragic fire?
Going rate for Female companionship, Lockhart Road's "red light" district?
Larcenous "elections"?
Or "fake news" in general?



The French rig is about 60 feet away "in the metal". First exposure, I rated it a Royal Pain in the Anatomy ... vs "conventional" Tee slots.

Then realized how dirt-simple, fast, and CHEAP it was ...to source pre-ground STEEL- or "face" it to target thickness in the 4-J... then drill a few holes with decent accuracy.

As-in the OEM one can serve well-enough as template for locating the hole layout.

Always an infinite number of ways to do stuff wrong.

But always more than ONE way to get it RIGHT, too.

And a Tee-nut "ground" to be flush under nought but the "vertical" influence of its tiny jack-up binding screws? WILL STILL need clearance relief.. lest the more aggressive pull-up of the QCTP centre post elevate it above the compound rest, either side, removing not only the extra resistance to spin, but robbing it of greater support against tilt from cutting-tool forces than if tighter to compound top, either side than to the tee nut, alone.

So I think we are on the same page for THAT point, at least? "Flush" isn't, really.

 

[eKretz]

Why they don't do that at the factory? Remember that the error in a lathe cross slide is or at least should always be in favor of a concave facing cut as opposed to a convex one. So, if the base of the tool post was faced in a lathe, it probably is slightly concave.

Aloris toolposts are ground... Pretty sure most of the quality toolposts out there will not be left with an as-turned finish.

 

[Shaun5]

I took ~0.01 off the top of the T-nut, made sure the stud is still recessed on the bottom of the T-nut, tightened it with the same ugga duggas and now rock solid. I didn’t measure the clearance, but can see light between the post and T-nut.

I’ll still make a tighter fitting T-nut with gap / round in the corner of the pulling surface when I come across a suitable drop.

Thanks.