T nuts

[chris pachinkoParticipant @chrispachinko]

Hello world!

 

I’ve bought my first milling machine, and know pretty much nothing about it. The specs say it has 12mm T slots. I thus bought a 12mm clamping kit off evilbay.

 

The T nuts in the kit are 10.7mm wide and feel to be fairly poor made. The seller tells me ‘they’re all like that sir”, and of course I don’t know if I’m being fobbed off. I’d have thought a nut for a 12mm slot would have been 11.5mm?

 

It possibly doesn’t help that my 12mm slots are actually 12.2mm. is it safe / clever to use the nuts?

 

Thanks,

Chris

[chris pachinkoParticipant @chrispachinko]

[JasonBModerator @jasonb]

The width of the upstand makes little difference to the holding ability, what matters is the width at the bottom so the upward clamping force is well spread. Just make sure the stud if screwed fully in as there is not much metal around the M10 thread in teh upstand.

 

EDIT just been out and measured mine at 10.8mm and not had any issues with them in 5-6yrs

 

EDIT 2

Just looked at my J&L cat and for M10 nuts the upstand is 11.7mm certainly tighter but at £3 a pop thats a lot to pay for a bit more metal.

 

J

 

Edited By JasonB on 06/01/2012 19:04:35

[,Participant @nousername29627]

Now you’ve got a milling machine why not make your own?

Make them ‘more rectangular’ so there’s more metal in the bottom of the tee slot to spread the load further i.e more length running along the direction of the tee slot.

 

Phil

[Alan Worland 1Participant @alanworland1]

Chris, why not make your own? A good machining exercise with longer being better than shorter.

Made mine years ago and they have served me well!

 

Alan

[WolfieParticipant @wolfie]

I also have this very day taken delivery of my first milling machine. I have Harold Halls book a Complete Milling Course and I am going to faithfully follow it.

 

The first few chapters make up your clamping kit bit by bit and I am on with that as we speak . Best of all each chapter in succession shows you how to use said kit.

Edited By Wolfie on 06/01/2012 20:16:31

[chris pachinkoParticipant @chrispachinko]

Thanks chaps!

 

I would make my own, but don’t have a vice yet. I was planning to wait until a show in the hope of avoiding buying one that’s poor quality but looks pretty. Suggestions on good quality makes would be appreciated.

 

Chris

 

 

[Keith Wardill 1Participant @keithwardill1]

Hello, Chris,

 

I had your problem when I first bought my mill, but you don’t need a vice to make T-nuts. I got a piece of steel long enough to make several nuts, and drilled it in a couple of places, then bolted it down to the mill table on top of a packing piece. The hold-down bolts were simply bolts I ‘found’ that had heads that were big enough to fit in the T-slots (I ground the sides of the bolt-head to make them a good sliding fit in the slots – (short thick coach bolts are good for this) – then I was able to mill the steel in one length to make the T-Nuts – the packing helped protect the mill bed. All I had to do then was drill and tap the holes in the T-nuts (also using the mill and its co-ordinate settings to place the holes), then cut off each nut from the length and file the ends clean – I have about 20 I made up like this years ago. I used high tensile ‘all-thread’ from the local DIY to make up the studs. Then when I had finished, I could use the T-nuts to hold down my new vice!

Then I couldn’t find a decent vice I could afford, so I made one myself eventually using the mill to make most of it, and the thread and nut from an old scissor-type car jack found in the scrapyard – similar to Acme, and very strong.

[Steve WithnellParticipant @stevewithnell34426]

Suggest you get a copy of Harold Halls book, it’s the best I’ve seen as a book to take you from absolute beginner to a reasonable level of competence.

 

A machine vice isn’t necessary for a lot of work, …like making T-nuts! T-nuts are a good practice piece. If the “up stand” is a sloppy fit they don’t jam in the slots quite so readily, so a good fit is not a “good thing” in this instance. Following on from wotsit, I use the metre lengths of threaded rod too. I always cut a new length to suit the task at hand, if the correct length isn’t in the box. That way you build up a good stock of various lengths, which doesn’t happen if you keep shortening the ones you made earlier!

 

Enjoy, I’ve had a lot of fun with my Mill (Harold’s book).

 

 

Steve

[Clive FosterParticipant @clivefoster55965]

Don’t care much for DIY store threaded rod. Generally a very slack fit in tapped holes.

 

Much to be said for using light alloy for Tee nuts. If you do trap a bit of swarf it grinds into the nut where you can get at it for removal rather than sticking into the underside of the Tee slot from whence it takes serious creativity and numerous words of power to dig out. Also if you do get over ambitious with the spanners the nut will strip before the table is damaged.

 

MDF / Chipboard / other improved wood sheets as used on kitchen cabinets and flat pack furniture makes excellent work holding plates if you don’t have a vice or the job won’t fit. Just break out the power driver and DIY screw box. Either fit holes in “spare” parts of the stock or use whatever is handy for clamp bars. Handy on the drill press too. Given the intended application the stuff is silly flat, although its best to check with a straight edge as sometimes there are ripples. Totally disposable once there are too many holes or milled out bits to keep using as there is always some-one nearby doing a kitchen. Easy enough to get as much as you need. Might have to donate an hour or two of help tho’. (Don’t underestimate the strength of such cabinets. Well up to workshop tasks with a bit of re-engineering such as proper solid backs and screwed on angle strips for positive fixing of shelves etc.)

 

Clive

[Keith Wardill 1Participant @keithwardill1]

Sorry Clive – can’t agree with you- I have never had hgh-tensile, rustless threaded rod strip out, even under extreme loads.

 

This is not rocket science, and I for one begrudge the time needed to set up the lathe and make ‘precise’ studs – not an easy task at the best of times. I think the point here is that Chris asked for advice, to get him going, and it is very quick and easy to make studs of any length as required from commercial studding, as Steve has mentioned. They can also be thrown away with no big loss if they are damaged, as will inevitably happen at some time. Commercial threaded rod is not so imprecise that it will strip so easily.

 

I would also never use ‘light alloy’ nuts – I consider they are far more likely to strip out under enthusiastic use of the spanner than steel nuts. There is also the risk of studs jamming in light alloy, requiring some effort to get the nut and stud out of the mill table. Haven’t we all had a tap jam when tapping some light alloy or aluminium? Maybe this is why standard nuts are not made from light alloy?

 

[MICHAEL WILLIAMSParticipant @michaelwilliams41215]

One thing to watch for on any T nuts whether bought or DIY is the radius where the upright leg meets the bottom flange . This MUST be almost non existant otherwise the T nut flange can sometimes bed only on the lip of the table flanges and this causes distortion and sometimes breakage .

 

MW

[Ady1Participant @ady1]

I would make my own, but don’t have a vice yet.

Have a go at making a decent vice.

I broke a couple of vices, one of which was a really good one.

Most vices are made of cast iron which is a VERY poor material for tension(the opposite of compression), so a really strong cast iron vice has to be pretty massive.

Cast iron is not bad for compression and has pretty excellent wear properties (lathe beds), but it’s not a happy bunny under tension.

I made a very simple steel one from a big round billet plus it’s far more compact and stronger than any cast iron equivalent.

It’s really just a bolt down g-clamp.

 

 

Well worth the effort making one yourself, 99% of vices are cast iron.

 

A solid steel vice for a lathe is pretty rare, and a tool for life.

Edited By Ady1 on 08/01/2012 13:37:44

[Sub MandrelParticipant @submandrel]

There’s studding and studding. Good quality rolled stainless studding is great stuff – I used a bit for the leadscrew on my grinder.

 

The cheap stuff at some of the DIY sheds is gruesome. It bends, stretches and strips at the slightest provocation, and doesn’t even have a nice finish.

 

Neil

[Francis SykesParticipant @francissykes95134]

I bought a 14mm set of tee nuts when I bought my new milling machine. The were a little too wide at the base to fit the T slots on the machine, so my first ever milling job was to reduce the width slightly. Fit of the narrower section of the T slot was perfect though. I don’t know how strong a standard exists on T nut/slot dimensions, or perhaps it does exist but is one of those that the Chinese manufacturers don’t apply very strongly. Easy job though and sorted now.

 

As for needing a vice to make tee nuts, as said earlier, why not just drill the ends of a strrip and use suitably sized bolts for the moment to clamp it to the milling table?

 

Studding, I guess it is very variable. Last studding I got I think was M8 or M10 – it was for making a small tool for pulling suspension bushes into place in situ on Mrs Sykes’ Fabia. It was stainless, and did the job okay, although I think it was on the limit of its capability. Other studding can be like toffee. I guess there is just huge variability.

 

Ady – like the vice – any chance of a close up picture?

[Gordon WParticipant @gordonw]

I don’t have a mill, but would think the most important thing to watch with T nuts is that the studs do not bottom in the slot and jack up the nut , this is an easy way to break a table.

[Ady1Participant @ady1]

Just simple coarse engineering, it takes up to 3 inches of stock.

A 10mm stud is holding things at the moment, when it goes a 12mm will replace it and finally when I can be bothered I’ll fit a flush insert with a square thread.

 

Squareness is the most important thing, which was all done in a single session on a shaper.

 

 

 

Been fine for all my needs so far.

Another advantage is it can be drilled full of holes to fit the shaper, cross slide or milling tables, which are all different dimensions, and with no loss of integrity.

You can’t do that with cast iron, it would be fatally weakened.

 

 

I use bits of square/flat stock and old vice inserts as required for jaws

 

 

Edited By Ady1 on 09/01/2012 10:32:22

[Gone AwayParticipant @goneaway]

I made a simple, low profile vice for milling that uses the machine table for the body (so it’s capacity is close to the table length). It keys into the table slots so is self aligning. The pics (if I can get them to load – never tried this) should be pretty much self explanatory.

 

 

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