Confusing t-slot dimensions

.

Just looked at it in your album, Howard

https://www.model-engineer.co.uk/albums/member_album.asp?a=54610

Clicking the thumbnail there opens it full size

MichaelG.

Edited By Michael Gilligan on 21/02/2021 12:04:16

No idea how that happened! I've added a link in the original, Howard's picture should look like this:

Dave

Hello,

As you are fairly new to machining, may I suggest that acquiring a few good books may help, if you haven't already got some that is. The first item in this book is how to make tee nuts, widely available for £6 or so.

There are also two new books on Milling and turning advertised top left of this forum.

Mark.

edit: Top right I mean.

Edited By Mark Easingwood on 21/02/2021 12:28:08

Thank You to all who enlarged the image. Much appreciated.

One thing to add for anyone going to make one.

Having made up the goalpost and clamped it in place on the T slot, take a skim along each side.

In that way, the surface to which the vice clamps before being bolted to the table will be in the plane in which the cutter moves.

Based on the occasional check, it will align the vice to about 0.001" (0.254 mm )

I even made one for my 3 way tilting vice!

Howard

Sadly, not practical on my little mill as it only has one slot in each axis. But I get the general idea.

As I'm getting a clamping set that comes with standard t-nuts for the mill, I may as well take the file to a couple of those to get me started - should be easy enough and there would be no need to worry about squareness as the top surface and threaded hole would be intact. Would only need to file the bottom and the sides of the spigot.

Had wondered about the stud going thru - makes sense to stop that with the staking

Photo of Hauser Mill

Edited By Kevin Cobley on 21/02/2021 13:47:16

If you make the goal post, and add spacers between the posts and the cross bar, using the X axis slot.

you can use the idea..If you pick the right post spacing, it may be possible to make one that can also align a vice in the short Y axis slot.

If you are determined enough, you will find a way!

Howard

I have a couple of these - the lathe basics and the lathe course. The lathe course was not great, so far - some of the clamping arrangements were risky (e.g. for fly cutting in the lathe) and key bits of info glossed over at points - I guessed I learnt what doesnt work in a few places..

For the price, I may get the milling course too. I do have lots to learn, though I suspect my mill is too unusual for the book - might have to scale everything down

Hopefully, those books set out the basics. Once you have a sound understanding, you build on that foundation.

NOTHING succeeds like success. But walk before trying to set a new world sprint record!

Howard

I'm sure thats right, but the lathe course leads you down paths in the first project that are not well thought out. The fly cutting arrangement was to clamp the workpiece against a slot in a vertical plate clamped to the cross slide. My machine already came with such a drilling jig. The book shows a small engineer's clamp holding the work against the slot, and you are required to fly cut to within 10mm of the base, so the clamp size is determined - it looked dodgy to me, but then thats what the course asked for.

The result was that the fly cutter just rotated the work in the slot even on a very gentle cut. I tightened the clamp as tight as I dared and tried again, and the result was the same, even with a tiny cut. It just doesn't work. Had to resort to a hand file to clean up the mess made.

Starting off by putting the student into the realms of questionable practice is not a great way to inspire confidence.

Edited By Kevin Cobley on 21/02/2021 14:24:53

I had exactly the same problem at the museum. The only way out was to make custom nuts. The advantage of making them is that they can be a much better fit than bought ones. I made them out of key steel. We have two mills, a rotary table, a lathe faceplate and a shaper cube, all different.

Slightly off piste, but I am a great believer in beginners learning their trade slowly. A newbie setting out to build a loco or traction engine as a first project is likely to end in tears. The result will be wasted material, time, and probably a disillusioned and disappointed incomer, possibly with damage to the machine and themselves.

Day 2 is not the time to be cutting a left hand buttress thread, nor to refurbish a 60 year old machine. Unless you know what you are doing, it may well look pretty but be less precise than before the job was started.

That was why about eight Apprentices were supervised by a very experienced Instructor, who patrolled the section to oversee and advise, interspersed with sessions in the classroom to instill theory as well as practice.

Mine use to be frustrated by our taking ten thou a side cuts on a twenty one inch swing lathe with a 10 hp motor.

When we gained enough experience, and confidence, to be taking off a quarter of an inch a side, he knew that his teaching had borne fruit!

On Milling, it was the overambitious who smashed cutters and had things moved along the table, rather than those who proceeded more timidly.

Newcomers don't have that advantage, even as members of a Model Engineering Club, having to go solo very soon, so need to proceed slowly and with caution. The need to read and learn the basics is MOST important

Members on this Forum will do their best to advise, but nothing can match Face to Face, and Hands On demonstration.

Before some says "All right for you, You spent your life machining" NO, I didn't. After a year I left the training school and it was over 20 years before I next handled a machine (A Cincinatti mill.) to show the night shift what to do.

I still have my basic training notes from 1958, and refer to them occasionally..

Howard

Edited By Howard Lewis on 21/02/2021 15:33:22

Howard. Presuming that you use Windows you can press "Windows key + E" to open file explorer to find your picture without loosing a reply you are typing. I am sure that other O/S' have a similar short cut to files & albums.

Or another way is to copy your text then repaste it into the reply box when you come back to it.

regards

Not sure I understand your thrust, Howard. Ten years ago I tried to take up a course but it kept being cancelled and then the course died altogether. I have done a fair bit of turning, at school and on my engineering degree, so coming back to it nearly 30 years later I started off by resisting the urge to dive in and deciding to work through the a-fore mentioned book. I don't think I'm 'rushing' in. These days one has to rely on youtube and the kind assistance of folk on the forums.

The milling machine I bought is small enough for my space, and cost less than modern machines of a similar spec, but is clearly made to do the job properly, unlike many modern machines. It doesn't need refurbishing - its in very good shape with little wear and having obviously been looked after. My target projects are small stuff to which its well suited. What else would you suggest? I don't hanker for a bridgeport.

What I don't have is a cupboard full of tooling. The lathe course assumes you have all manner of accesories, for instance, like a fixed steady, and drilling jigs or vertical slides - my lathe happens to be fairly well provisioned, so I was OK*. The Mill came mostly bare, so I'm starting to acquire a vice and need a workholding kit and some cutters. I'd like to start by making more stops for it, for instance - not too ambitious.

So I started with a clamping kit on my shopping list but came unstuck immediately, hence the post. Others have explained that this is normal - thats understood, and now my first project will be some t-nuts. Whats the issue?

Kevin.

* my lathe came to me via a friend at a price that was a bargain. But the lathe has been 'tinkered' with extensively, presenting its own challenges. The fixed steady for instance, has bearings attached - their hard shells marr the work - lesson learned - mod. will be removed before I use it again. There are a number of other strange things about it that I have to work around, like the boring out of the spindle to accept 2c rivett collets which means it no longer has an MT, which could be lived with if the collet nose had not been lost at some point...

Edited By Kevin Cobley on 21/02/2021 16:03:41

To get a reasonable size for the nut threads, measure the width of the slot first. If the slot was 12mm, for instance, 12 mm would be too big, so 10mm would the sweet spot. If you are starting from scratch, then metric is easier, much more freely available and metric lengths of studding are common. Studding is usually 8.8 medium tensile strength, which is ok for most work. Custom nuts can be a bit longer which spreads the loading in the slot better than bought ones.

Hi, or maybe even right click on your Albums in the green bar and scroll to open in a new tab or window.

Regards Nick.

.

I think enough advice has already been given about t-nuts in general ... so can I just congratulate you on the little Hauser, and mention that, at that scale, t-bolts can also be very useful [and do not occupy much storage space].

MichaelG.

Kevin,

I was not accusing you of "rushing in" But some do, and find themselves in trouble that would not have happened if they had learned the basics, first of all.

I won't name names, but there have been threads which illustrated "Fools rushing in where angels fear to tread"

It may be easy to take something apart, but if parts fly out onto the floor, you don't even know what you are looking for or how it goes back together And I have a few Tee shirts, hence my more cautious approach.

No one should buy a Cessna 150 and take it straight out to the end of the runway, any more than a non electrician wiring in a 3 phase motor.

The problem are those who, as a colleague once put it "Don't know that they don't know" They won't be told that an elephant is not a fast food snack!

I have been in Engineering all my life, but when the Apron needed to come off the lathe, I sought the advice of those who had done it before. And picked up some useful tips, without having problems.

Having been Technical Assistant, and then Engineering Superintendent, I have experience of many buses and coaches, a long time ago, but would not fancy taking out of the latest complicated ones without a lot of instruction.

My motto is not to bite off a lot more than you know that you can chew.

Hope that this clarifies the position.

Howard..

Kevin,

You are right about tee nuts, they are very simple, generic and only the slot width matters. I have 3/8 wide slots on my Centec which means a 8mm bolt goes through with a bit of wiggle room. Guess what, an 8mm Warco tee nuts fit and being as then they were 50p each I bought 10. For that money I really don't see why you would bother to make them.

Use studding or make tee bolts with thread lock and not hex head bolts and use a 4" spanner so you wont break anything (the studding will strip first)

.

... and please don’t think that I was suggesting any such thing !!

MichaelG

.

Call me pedantic, if you must, folks ... but I’m disappointed to see S1 = S2 in those tables, and both expressed only in whole millimetres.

... Does anyone know what Standard is being referenced there ?

MichaelG.

.

https://www.engineeringtoolbox.com/t-slut-t-nut-size-metric-d_2072.html

Edit: __ looks like it’s DIN 508

See: https://www.berger-tools.co.uk/Din508_TNut_Heat_Treatable_Steel/

Edited By Michael Gilligan on 21/02/2021 18:31:11