T-Slot Dimensions

If it isn't too much trouble, could anyone with 22mm or "28mm" t-slots provide their dimensions please?

It seems what the Machinery's Handbook lists does not necessarily coincide with some tables, or the dimensions may vary greatly from manufacturer to manufacturer.

Thank you

I don't quite understand what you're getting at.

If, as you say, some manufacturers do not produce table slots to the dimensions shown in Machinery's Handbook, are you wanting to know what variations are out there?

TGTool said:

I don't quite understand what you're getting at.

If, as you say, some manufacturers do not produce table slots to the dimensions shown in Machinery's Handbook, are you wanting to know what variations are out there?

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The grooves fall within the dimensions of the Machinery's Handbook.
Do many machines exist with a 28mm wide throat? I have only seen 27mm 1.062
Metric slots vs. standard

The throat depth does vary greatly depending on the manufacturer.

Every one of my mills has metric T-slots. None of them seam to follow that chart at all. The slots are on size and ground. I regularly use on size gauge pins to locate fixtures in T-slots on my machines.

I have one machine with 22mm wide T-slots. The slot width is 22MM.

Garwood said:

Every one of my mills has metric T-slots. None of them seam to follow that chart at all. The slots are on size and ground. I regularly use on size gauge pins to locate fixtures in T-slots on my machines.

I have one machine with 22mm wide T-slots. The slot width is 22MM.

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Thank you for your reply, that is great to know.
Our machines are nominal as well, 16mm | 18mm.

It appears some of our customers have 27mm (American standard) t-slots, and some have 28mm, but both refer to them as 28mm which caused confusion.
22mm actually being 22mm seems to be the standard.

I do not understand what you are doing. And I wonder if you do.

1. Do you have a set of tee nuts and bolts and want to buy a machine that they will fit?

OR

2. Do you have a machine and want to buy tee nuts and bolts that will fit?

OR

3. Do you plan to manufacture a machine or accessory with tee slots?

OR

4. Do you plan to manufacture tee nuts and bolts?

OR

5. Some combination of the above?

My answers:

1. You are foolish so I have no answer.

2. Just measure your machine's tee slots and buy nuts to fit. This is what I had to do for my mill when I discovered that the tee nuts in the standard(?) 1/2" clamp set that I purchased did not fit. I have about 6 or more tee nuts you can have for postage.

3. If you are planning to make a machine or accessory and are asking such a basic question, I would suggest that you put your money into a treasury bond instead. You will be much further ahead in ten years. But if you must go ahead with this, then buy one or several of the import sets and measure the nuts. That will probably be a good starting point.

4. Tee nuts and bolts are sold with a variety of (head) sizes just because of this problem. Any serious manufacturer will make an assortment of them or will lose many sales. You can look in published catalogs to see the various sizes that are presently being sold.

5. Pick and choose from the four answers above.

EPAIII said:

snip.

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What crawled up your ass?

Sent via CNC 88HS

Oh, so you can tell us what he is asking?

Fire away!

Cole2534 said:

What crawled up your ass?

Sent via CNC 88HS

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EPAIII said:

I do not understand what you are doing. And I wonder if you do.

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A quick search for "Octane Workhold" shows that the guy actually makes a small product line of things that work with [gasp] T-slots.

Octane Workholding- Fueling Your Innovation – Octane Workholding LLC

So he's trying to figure out what the "real world" geometries are for T-slots for extant machines. Apparently he's run into situations where a product that's supposed to fit an application doesn't, due to manufacturer variations, so it's a reasonable question to ask.

EPAIII said:

Oh, so you can tell us what he is asking?

Fire away!

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Yes, I can, because he explained it in plain English. There was a discrepancy between a nominal dim and the actual size and he was asking for clarification.

It appears some of our customers have 27mm (American standard) t-slots, and some have 28mm, but both refer to them as 28mm which caused confusion.

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And, since I own some of his products, I can vouch for their quality as well as Octane's good customer service.

Octane, if you revisit this thread- Has your team received any feedback on a good corrosion inhibitor to apply to the slots prior to installing the covers.

Well, that does shed some light on what he is doing and what he actually needs.

I have been made fun of, but I do not see any serious answers from anyone here.

27mm is VERY close to 1 1/16" which is exactly 26.9875 mm. The table he shows in his original post shows 1 1/16" to be 28mm while it is, in fact LESS than 27mm. I see other discrepancies in that table such as 1.000" being equivalent to 24mm. When I checked the table in Edition 26 of Machinery's Handbook, it appears that it is identical to the one he posted including the same errors.

So, if he has been using that table and not realizing the discrepancies in it, it is no wonder that he is having trouble with his products. Since we still do not know weather his problem is with the slots themselves or with the nuts that will fit those slots, it is still hard to provide any specific advise. All I can say is that he needs to analyze each situation he is having trouble with and perhaps use a dimension which will work with both extremes of the values given in that table.

He should also take note of the fact that that table is labeled as an AMERICAN standard (American National Standard T-Slots ANSI/ASME B5.1M-1985 (R1998)) which implies that it is an English measure standard, not a metric one. So it makes little sense to talk about metric sized Tee slots while using that table. Does anyone have access to any metric standards for Tee slots?

And that table, dated 1998, needs to be revised by a proper group of design engineers to eliminate glaring discrepancies such as the ones listed above. Since manufacturers around the world are apparently interpreting this table in different ways, that is not going to be an easy or trivial task. But it still should be done.

And what I said about the Tee nuts being available in a variety of dimensions for a given supposedly standard size of slot was not an exaggeration. This IS a serious problem and one that should have been resolved decades ago, like in the 1920s for heaven's sake. They sure get a lot of money for a reference that is so poor.

Milland said:

A quick search for "Octane Workhold" shows that the guy actually makes a small product line of things that work with [gasp] T-slots.

Octane Workholding- Fueling Your Innovation – Octane Workholding LLC

So he's trying to figure out what the "real world" geometries are for T-slots for extant machines. Apparently he's run into situations where a product that's supposed to fit an application doesn't, due to manufacturer variations, so it's a reasonable question to ask.

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In my other two posts I suggested that catalogs that feature Tee nuts would be one source of information. Here is one such catalog reference.

McMaster-Carr

And another one:

https://www.mscdirect.com/browse/tn/?searchterm=T slot nuts&hdrsrh=true&rd=k

The only conclusion you can draw from these is that the standards for these slots and nuts are anything but standard.

And, unfortunately, the dimensions of the nuts does not directly translate to the sizes of the slots that they fit. There is a LOT of clearance involved between them.

Looking at chart here you can see how confusion can arise when quoting nominal metric equivalent.

Dimension Table for T-Slots, Bolts, and Nuts Table Chart | Engineers Edge