FP2/12mm T-nut dimensions

sigurasg · Dec 30, 2020

Hey y'all,

Is there a spec for what a T-slot nut for 12mm slots should look like? I'm about to make a batch, but I don't think I have a good sample to work from - nothing that looks original in any case.

I bought a 3/8" clamping kit, but the T-slot nuts seem a little anemic on the shoulder, and they seem quite rounded all over. I'm worried that I'll maim the underside of the T-slots if I gronk down on them at all.

I made some nuts with 10mm thread but those seem to fit a little too tight. Here's a picture of the 3/8" roundballs back-to-back with one of my fatsos:

Siggi

ballen · Dec 30, 2020

Hi Siggi,

It is DIN508 and DIN508L. Dimensions are listed here: https://amf-embedded.partcommunity....mesp/mesp_media/english/amfdin508_english.pdf

You can download the AMF CAD model from here:
https://shop.amf.de/application/amf_app000000?ACTIONxSETVAL(artlist.htm,APGxNR

IN%20508,AKATxNAME:eshop,APPL:AMF,DIR:shop,ANZ_SPRACHE:,USERxSEITE:Liste)=Z

You probably want part number 80036.

It's a good idea to avoid low quality nuts with rounded internal corners and only use nuts with a small inside corner radius. I've bought mine from here, they are good quality and cost 1.15 Euro for normal ones and 2.00 Euro for long ones. Not worth making them myself at that price. I normally use the long nuts rather than the short ones, to spread the load more.

OREX Muttern fur T-Nuten DIN 508 M6-M22 T-Slot Spannpratzen T-Nut | eBay

Cheers,
Bruce

sigurasg · Jan 1, 2021

ballen said:
I've bought mine from here, they are good quality and cost 1.15 Euro for normal ones and 2.00 Euro for long ones. Not worth making them myself at that price. I normally use the long nuts rather than the short ones, to spread the load more.

OREX Muttern fur T-Nuten DIN 508 M6-M22 T-Slot Spannpratzen T-Nut | eBay

Thanks. That seller doesn't offer shipping to Canada by default, and NA-based sellers with similar T-nuts seem to want a kings ransom for them. I've sent the seller an inquiry about shipping to this here frozen Tundra. I figure I'll still want to make some nuts with 3/8"-16 thread to use with my clamping kit.

rimcanyon · Jan 1, 2021

Is there also a spec for metric t-nuts with imperial threads?

I have machined all my ⅝ x ½" t-nuts to 14mm to fit the fp2NC, but I have tight spots in the t-slots so I think I should have made the fit more loose. My inside corners have a small radius and some of the t-nuts wedge into place.

Bill Fisher · Jan 1, 2021

sigurasg said:
Thanks. That seller doesn't offer shipping to Canada by default, and NA-based sellers with similar T-nuts seem to want a kings ransom for them.

That seems common with ebay items from Germany but can be overcome by using a freight forwarder. I have had success with mailboxde.com, based in Germany.
Bill

rimcanyon · Jan 2, 2021

Bill Fisher said:
That seems common with ebay items from Germany but can be overcome by using a freight forwarder. I have had success with mailboxde.com, based in Germany.
Bill

If you use mailboxde.com, how do you avoid paying VAT on purchases?

ballen · Jan 2, 2021

rimcanyon said:
I have machined all my ⅝ x ½" t-nuts to 14mm to fit the fp2NC, but I have tight spots in the t-slots so I think I should have made the fit more loose. My inside corners have a small radius and some of the t-nuts wedge into place.

The dimensions given in my earlier post indicate that the nuts should have around 0.3mm ~ 0.012 of clearance in the slots.

sigurasg · Jan 15, 2021

So I made up a batch of nuts.
Mine are a smidge under 19mm wide on the wide part, and around 11.8mm on the narrow part. They stand about 9mm tall from the shoulder to the top. Fit like finger in glove.

First time I power tap in the Deckel, it works like a charm. However, when I programmed the VFD, I made the "jog" button run at 10% speed, figuring this'd be how I reverse out of tapping. Never used it until today, and I can unequivocally state that it's totally and utterly useless.
Maybe a dedicated button for a full-speed reverse jog would be worth it?

Now, I was going to make the shoulder 7mm thick, but I had an unfortunate endmill pullout problem. Put a skidmark on my fixed jaw too.
I don't feel this was a particularly aggressive cut, 5/8" rougher about 1/8" in, ~0.350 deep, running at 315RPM at 5IPM for about 4thou/tooth. My FP2 certainly wasn't complaining, though the other side I did at 2.5IPM without trouble.

This begs a question to me about the holding power of E355/U2 collets. Do I need some other way to hold "larger" endmills, or just put more grunt on the drawbar when I tighten up?

rimcanyon · Jan 16, 2021

sigurasg said:
So I made up a batch of nuts.
This begs a question to me about the holding power of E355/U2 collets. Do I need some other way to hold "larger" endmills, or just put more grunt on the drawbar when I tighten up?

I have to admit I have no idea what E355/U2 collets are, but I need to ask, why does the drawbar have anything to do with it? When I tighten collets, that is done in the vise before mounting the tool holder in the arbor. If you are depending on SK40 drawbar to tighten collets, my suggestion is to get another system, something where the collet holding power is independent of the drawbar tension.

sigurasg · Jan 17, 2021

rimcanyon said:
I have to admit I have no idea what E355/U2 collets are,

These are "Deckel-style" collets, they look like this:

.
They have the SK40 buttress thread on the back of them, and they pull into a collet adapter that has the 40 taper on the outside.

rimcanyon said:
but I need to ask, why does the drawbar have anything to do with it? When I tighten collets, that is done in the vise before mounting the tool holder in the arbor. If you are depending on SK40 drawbar to tighten collets, my suggestion is to get another system, something where the collet holding power is independent of the drawbar tension.

So far I'm mostly working with the tooling that I got with my mill, which included a near-complete set of these collets to 5/8". Naively I figured they'd be sufficient for holding arbitrary tooling to their size, but clearly that's not the case.

Apparently Ross thinks they're good only to 10mm tooling or so, so I guess I'll be looking for something better.

Sounds like perhaps ER32 would be a good choice?

AlfaGTA · Jan 17, 2021

Dave:
The question here relates to the manual machines....
The direct mounting #40 collets used on the FP2/3 are fine for moderate cutting. Here the clamping force is generated via the draw bar tension.
My sense is that those E355/u2 collets just won't hold the too tight enough when the diameter gets above 3/8"(10mm) or cuts and depths get aggressive.

For my money think the Deckel collet holder as shown is pretty good.....Has a long taper on the collet that gives high gripping on the tools....(similar to the TG 100 setup)
Really don't know the part number or type number. The one i have has the Deckel logo on the body along with a size range marking of 4/25mm and nothing further. I am sure some smart person here will fill in the blanks
Note the drive keys....

Collet, note the long taper (better than an ER IMO.

On my FP-NC's i have two different tool holding setups.
For smaller tools and holding reamers and drills i use ER 16. Works fine to 10mm.

Above that i use the TG100 collet holding setup....Prefer these over similar sized ER collets because the main taper on the TG is less steep than the ER and the holding power is just better.
Not as flexible for off sized tools is the down side , that and the TG might be difficult to find with a Deckel style shank/draw bar. For the NC's plenty of CAT 40 holders out there that will carry a TG collet.
When i am going to work the tool hard (not finish work) i often will use an end mill holder (Weldon style) where the possibility of pull out is eliminated by the set screw.....

Cheers Ross

ballen · Jan 17, 2021

AlfaGTA said:
For my money think the Deckel collet holder as shown is pretty good.....Has a long taper on the collet that gives high gripping on the tools....(similar to the TG 100 setup). Really don't know the part number or type number. The one i have has the Deckel logo on the body along with a size range marking of 4/25mm and nothing further.

Here you go. I think these are type "OZ" collets.

I only have this in German but it's pretty self-explanatory. The last six collets listed are for tooling which has an outside thread.

sigurasg · Jan 17, 2021

ballen said:
Here you go. I think these are type "OZ" collets.

Interesting, looks like there are different series of these too. On FS' site they list
OZ415 (aka OZ16),
OZ462 (aka OZ25) and
OZ467 (aka OZ32).
Looks like they go to 16, 25, 32 mm respectively. Other than some incidental information, I can't seem to find a spec for those collets. Pretty shallow taper though, and looks like they have a 0.5mm clamping range.

ballen · Jan 17, 2021

Pretty sure it is OZ462 or OZ462E, aka OZ25, which goes up to 25mm shaft diameter

If you search ebay.de for the following you will find some:

Spannzangenfutter OZ462 SK40 s20x2

For example:

Spannzangenfutter OZ462 SK40 S20x2, Spannzangensatz D3-20 Deckel Frasmaschine | eBay

thanvg · Jan 18, 2021

sigurasg said:
...

This begs a question to me about the holding power of E355/U2 collets. Do I need some other way to hold "larger" endmills, or just put more grunt on the drawbar when I tighten up?

I still remember the part I scrapped on my first Euro mill using the E355 collet that let the end mill pull out.
And then I didn't learn and repeated it years later on the FP2. I said 'it just aluminium', but it did pull out

I, now, use E355 only for light cuts and/or when I don't have another option (small tools, reach etc). I also don't like having to remove the adapter when I need to change to another 40 taper tool so I avoid them.

It's gonna by mostly weldon for roughing (unless it's shell mill or MT tapered tool) then ER or direct 40 taper. I have never, yet, had any direct 40 taper collet let the end mill pull out.

ER are a reasonable option if you are on a budget, even buying from FS!

BR,
Thanos

ballen · Jan 18, 2021

thanvg said:
I, now, use E355 only for light cuts and/or when I don't have another option (small tools, reach etc).

It's the same for me. I use E355 only when I have small cutters (1-6mm). From time to time I also use it to hold an even or half-mm size drill bit with very low runout or if I for some reason am worried about the Albrecht 13mm chuck slipping.

AlfaGTA · Jan 18, 2021

I would off those E355's to some unsuspecting collector......get a direct mount 40 taper to ER 16 for the small stuff (10mm) and be done with it.....Tales the temptation out of the picture to use those crappy collets in an emergency.(which they will often create)..
OK for a single lip grinder, past that not so much.

As an aside, those collets (OZ?) used to be available here in the US from MSC. Sold under the name "Precision" ...Bought a set sized in inches at reasonable cost, think somewhere around $12.00 EA... Don't see them listed anymore, pity.
.
Cheers Ross

ballen · Jan 18, 2021

AlfaGTA said:
I would off those E355's to some unsuspecting collector......get a direct mount 40 taper to ER 16 for the small stuff (10mm) and be done with it.....Tales the temptation out of the picture to use those crappy collets in an emergency.(which they will often create)..
OK for a single lip grinder, past that not so much.

As an aside, those collets (OZ?) used to be available here in the US from MSC. Sold under the name "Precision" ...Bought a set sized in inches at reasonable cost, think somewhere around $12.00 EA... Don't see them listed anymore, pity.
.
Cheers Ross

Inch OZ25 = 462/462E collets are available in inch sizes from the "Vertex" company. Those are made in China (maybe Taiwan?) and the quality is good. Here's a link of the UK Ebay site:

Vertex OZ25 Collet 1/8 - 1" Industrial Quality DIN25 6388 Type A 462E | eBay

Apparently there is also a DIN spec for this, DIN 6388.

AlfaGTA · Jan 18, 2021

Bruce :
Thanks for that..Found these guys.....Looks to be Pacific Rim Manufacturer....Maybe ROC Taiwan.
Look to have some different setups including a Morse shank set....(for the FP1 guys) Would need a draw bar adapter thread at the end.
Stuff looks nice, but could just be the artwork.

OZ System

Cheers Ross

On edit:
Looks like MSC still caries these collets under the name of " 1"Full Grip"

https://www.mscdirect.com/browse/tn...llets/Specialty-System-Collets?navid=12108621

DennisCA · Jan 19, 2021

rimcanyon said:
I have to admit I have no idea what E355/U2 collets are, but I need to ask, why does the drawbar have anything to do with it? When I tighten collets, that is done in the vise before mounting the tool holder in the arbor. If you are depending on SK40 drawbar to tighten collets, my suggestion is to get another system, something where the collet holding power is independent of the drawbar tension.

Soooo I am doing it wrong when I am tightening the collets in place (on an SK40 ER-32 collet holder)? I usually put the machine in lowest gear and tighten it in place so I dont have to remove the collet holder from the machine.

FP2/12mm T-nut dimensions

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