Collet block C spanner

[colin hamiltonParticipant @colinhamilton16803]

[colin hamiltonParticipant @colinhamilton16803]

Morning all. I just bought myself a 5c collet block set and it would appear I need a C spanner to tighten the collet up. This wasn't supplied in the kit ( which seems odd to me). Could someone point me in the direction of a suitable sized one? Thanks Colin

[JasonBModerator @jasonb]

If no other reply I'll measure up the one I use a bit later.

[DC31kParticipant @dc31k]

In addition to 'C spanner', they are also known as 'hook spanner', so that might give more options when searching.

They are sized according to the OD of the nut so measure what you have. There is a table of sizes on this eBay listing, which might help:

https://www.ebay.co.uk/itm/194318571071

If there is an 'official' standard for them, it is DIN1810 (DIN 1810 specifies many 'Forms'. The one with the square prong is Form C).

https://www.ganternorm.com/en/products/3.2-Mounting-positioning-levelling-with-screws-clamping-and-supporting-elements/Nuts/DIN-1810-C-Spanner-Steel

If you have an ER collet chuck, try the spanner from that. It is the same type of spanner so it might fit.

[JasonBModerator @jasonb]

Had a but more time than I thought. I use a 38-42 one that has had the tip slightly ground so it fits in the hole rather than a slot.

The ring on mine is actually 42mm so you could also use a 40-42 pin type C spanner

Edited By JasonB on 13/01/2023 07:37:34

[colin hamiltonParticipant @colinhamilton16803]

I blinking love this forum!! Thanks to all for the speedy and detailed responses.

[noel shelleyParticipant @noelshelley55608]

Could try ARCeuro ? Noel.

[colin hamiltonParticipant @colinhamilton16803]

Posted by noel shelley on 13/01/2023 10:54:18:

Could try ARCeuro ?

Good shout, it's who I got the blocks from!!

[colin hamiltonParticipant @colinhamilton16803]

Looking at the price of the spanners with pins rather than lugs I might have a look at making one. Only question is will I need the collet block to do so!!

[Clive FosterParticipant @clivefoster55965]

Colin

This is the one I made perhaps 30 years ago.

Works well.

As I recall things I cut a 1/4" thick ring from the end of a piece of steel bar and cut it in half.

The pin was positioned by eye with reference to the collet block "nut" and welded in place before a bit of light filing to clean up to a

I cut the half ring down to what looked like a suitable length of arc and welded that to a short offcut of 1/4" plate. Bandsaw, file and linisher to finish off a bit smart with no sharp edges.

Objectively a bit more time and trouble on radiusing the edges with a bit more spit'n polish would have been nicer but made no difference to how well it works.

The taper on the handle makes it much more pleasant to use. Could have done a simple rectangular bar or even a rod but such tend to be unpleasant to hold. Sufficiently so as to make positioning harder. Learned a long time ago that tapered handles, large end out, are well worth the effort.

Clive

[JasonBModerator @jasonb]

You can also just use a tommy bar which is easier to make.

[Clive FosterParticipant @clivefoster55965]

Posted by JasonB on 13/01/2023 13:16:46:

You can also just use a tommy bar which is easier to make.

Jason!!!

In principle possible but trying to keep the thing well enough engaged to approach sensible tightness is likely to be a blood sport. A frustrating blood sport.

Its going flying at the first opportunity when you lean on it.

How do I know!

I tried, once, using the little tommy bar out of the horizontal – vertical milling table mounting 5C carrier. Tommy bar works OK on the H-V units because you only have to adjust the nut close enough for the tightening lever to work so its just turning a loose nut with no real leverage needed.

Used a small brass drift for final tightening on the collet block and worked around the workpiece not ending up where I'd ideally have liked.

C spanner construction started about 4 milliseconds after I'd cleared the machines!

These days I'd have made the spanner before finding drawer space for the block.

Its taken a decade or three for the penny to drop but I've finally come to realise its always best to take the extra time to make functional, easy and safe to use tooling / adjusters rather than steam in with the crudest thing that can be cursed into working. Takes 4 or 5 times longer to make but on balance you come out ahead after a few uses because the job goes so much quicker. Especially if accurate setting is required. Never forget your hands are likely to be slightly oily so grip less positive.

Hafta accept loosing on a few when it turns out the nice tool is for a job that pretty much doesn't repeat.

Still ahead overall.

Hate wiping oily blood drips off machines

Clive

[DC31kParticipant @dc31k]

There is a readable picture of DIN 1810 here:

It has enough information to draw up one to suit any size in the range.

One of our expert 3D CADists could make a parametric model for us so we input a nominal diameter and it gives us a correctly-dimensioned drawing.

The challenge in the making is to ensure the axis of the pin passes through the centre of the curve.

[Nigel McBurney 1Participant @nigelmcburney1]

ARC euro list ER collet wrenches which engage with 4 slots in the collet nut,the one that I use is painted green and shown on ARCS web catalogue,these grip better and less liable to slip plus the handle,they are strong and take fair amount of abuse,lot better than C spanners,

[JasonBModerator @jasonb]

The rings on the 5C blocks are not slotted like ER nuts, they are a knurled ring with 4 radial holes

Edited By JasonB on 13/01/2023 19:41:42

[colin hamiltonParticipant @colinhamilton16803]

Clive, I hope you don't mind but I copied your spanner!! It works fantastically. Thanks for taking the time to post the picture.

[bernard towersParticipant @bernardtowers37738]

On the subject of collet spanner’s I made a two handled spinner type for my ER collet nuts as I found the supplied spanner’s awkward to use. It’s been about 15 to 20 years now and wouldn’t be without it!

[Clive FosterParticipant @clivefoster55965]

Colin

Great. I'm glad it's worked out well for you.

Only sorry I no longer appear to have the drawings which would have made life a little easier for you. Pretty sure the original computer files didn't make a jump between machines and/or program upgrades in the intervening years.

Back then I didn't keep hard copies after making the item figuring I could always print again if need be.

Something I discovered to be a very bad idea about 20 years ago when having to recreate some moderately complex stuff with grossly inadequate information due to no longer being able to read, let alone print, the original files.

Clive

[JohnFParticipant @johnf59703]

Posted by Clive Foster on 29/01/2023 18:40:22:

Colin

Great. I'm glad it's worked out well for you.

Only sorry I no longer appear to have the drawings which would have made life a little easier for you. Pretty sure the original computer files didn't make a jump between machines and/or program upgrades in the intervening years.

Back then I didn't keep hard copies after making the item figuring I could always print again if need be.

Something I discovered to be a very bad idea about 20 years ago when having to recreate some moderately complex stuff with grossly inadequate information due to no longer being able to read, let alone print, the original files.

Clive

Never trust computers ! Useful but fallible ! A pencil and paper is safer.

I see you are all fixed up but for interest I have an adjustable one, available in different sizes.

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