New collets. Bankrupt now.

Gents,

After trying the Chinese cheap nasty collets I have ordered a set of Rego-Fix ER25 collets. Beans on toast for a month at least. In order to make them last for as long as possible I would like to use the c correct torque. I didn’t even know there was a torque spec bit there you go.

I was looking at this spanner thingy. Will it work? Seems to my amateur newbie mind to measure torque aroind the wrond axis. I need it measured around the green axis but coupled with a conventional torque wrench it would measure around the red axis wouldn’t it?

Will this work?

Thanks, Mark

It would depend on the position of the lever you use with it.

Torque is force x radius, so if the lever were at 90° to the C spanner it wont be far off.

Phil

You can get similar fittings but the sq drive socket is on the end and then use a matching wrench which has the sq drive poking straight out the end. may be beans for a while longer though looking at this

Mark, two things. One, you would have to allow for the additional moment arm because of the extra offset, and make sure you always inserted the square ended wrench in the same relative orientation.

Second, somewhere on here, I think it was Joseph Noci reported that tightening the collet nut with a single wrench can make the collet run slightly out of true, what you really need is a way to provide a balanced couple. I've provided myself with a socket that fits an ER16 collet so I can do this, but I'm not sure if sockets are available to fit the funny notched nut arrangment you show.

Phil, sounds logical. Thanks, that may be the way to do it then.

Jason, I had seen those but was suprised at the price.

John, I am interested in your socket. Do you have a pic? Is it a normal half inch socket modified to fit an ER style nut?

Hi there, Mark,

In my applied mathematics course (many, many years ago!! ) we were taught that 'a couple has the same moment about any point in its plane'.

Best regards,

Swarf, Mostly!

People like Norbar tell you the formula to use for their torque wrenches (it varies from tool to tool) when using an offset tool like this. It is necessary because you can buy spigot connections for welding your own fitting onto. I have had flat ring wrenches heated and bent then cut off and welded onto spigot connectors and set using a torque meter so that they can be used around obstacles. A suitable torque meter and connection is the easiest way to set a torque with an extended tool.

Is there a different torque for ball bearing nuts compared to plain nuts?

Martin C

You see this is why I hang around here

Excellent info and suggestions, many thanks. I will go the cheapest route first and see how I get along. Dad has a torque wrench so this little attachment will be a good place to start.

Martin, I have seen different torque values for ball bearing nuts, yes. My nuts are plain

Mark, ER nuts seem to come in two styles. Mine are mainly hex and that's what I have on the collet spindle that I've retrofitted to my Unimat. I needed a 25mm socket to fit an ER16 nut, but also a deep socket to clear the work or tool mounted in the collet. 25mm a/f deep sockets are like hen's teeth, but I found one that is designed for an impact driver. It comes in black finish rather than polished.

I also heave a mini collet nut that is cylindrical with slots to engage a wrench - I haven't seen a socket as such for this but bought a little tool with the nut from Arc - I made the collet holder, it's for my Acute sharpener to hold end mills.

Looking at the Norbar site they now have an app for calculating the result of extending the torque wrench.

Norbar apps page

Martin C

Excellent ... Thanks Martin

MichaelG

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Barrie,

I got them from Dixi Polytool. Their website is **LINK**

I am in the Netherlands but they probably have a UK shop too.

Mark

Thanks Martin!

Formula can't be that hard? As torque=force x distance, surely it's just:

actual torque = indicated torque * (distance from handle to pivot point)/(distance from handle to drive square)

Nick,

The second drawing is the clue here as Phil P said in the second posting. Thanks, that's a handy diagram to have.

Mark

When I do up the ER series bigger than ER16, I do it up with a tap with my copper block on the end of the spanner. Then I put the spanner on 180 deg and do it again. Sounds silly I know, but I have found this to create the most consistent results. Another company that make really good ER series collets, is the Big company from Japan. But their collets are over twice the price of the Regofix ones. I do find that the C spanner does not do the initial tighten to be as good as the mutli tooth ER spanner. However, when tapped from each side 180 apart, they seem to be the same result. I also found that some ER nuts are alot better than others for getting a consistent result. The Hex nut on my ER20 spindle, seems to be very good, even if only tightened from one side. A bad nut can cause a runout of 0.02mm easily , when a good one will result in a runout better than 0.006mm easily with the same collet and test piece or cutter. The part I don't fully understand ,is that the bad collet nut will often have the same run out at the nut face, but measuring the bottom of the pin, so like 30mm away, is where the differences are really noticed. The pin can be tapped to run true, but my thinking is, if it can be tapped true, it can chatter out of true as well. I have not found a Bad Regofix nut yet. The cheaper copies have definitely been the ones I have seen issues with, especially the bearing nuts.

Neil