Spare part for SIP 06851 WOODTURNING CHUCK SET

[Flippsie]

Hi,

I have a SIP 06851 WOODTURNING CHUCK SET. Given that it can be revolving at over 200 rpm, I thought I'd be really sure that, when I changed the jaws on it, the screws were nice and tight - didn't want one of them flying off. However, what I managed to achieve was the removal of the top of one of the screws - it just twisted off. Not something I thought I'd be able to achieve using the t-bar hex key provided.

I've asked SIP, they do not sell spares and advised me that I could pick them up on any site selling fasteners. However, I've trawled around a lot of these sites and I can't find a suitable replacement. The nearest I could find that matched the thread, had a head 10mm in diameter, but a replacement can't be more than 6mm!

Has anyone else had this or a simpler problem in sourcing spares for this chuck? Any suggestions as to who could supply these hex socket screws?

Thanks,

Flippsie

 

[Phil Pascoe]

Something like
https://www.namrick.co.uk/cgi-bin/sh000 ... 38?a316253
You'd need to know the size, obviously. If you search this site, this has come up before, iirc.

 

[Flippsie]

As I said, I've been to a lot of sites of this type, and none of them have a screw of the right dimensions. The one suggested was the same. These screws seem to be specific to this SIP chuck.

 

[NazNomad]

The nearest I could find that matched the thread, had a head 10mm in diameter, but a replacement can't be more than 6mm

What size thread?

 

[Flippsie]

Hi,

Using the diagram below:

L=11.5 mm
H=2.7 mm
D=6 mm
N=1 mm
V=3.5 mm
A=3 mm

Does anyone know of a company that would make custom fasteners?

Thanks,

Flippsie

 

[J-G]

There is a great deal wrong with those dimensions and I doubt that anyone would make them - I certainly wouldn't even try and I do make my own down to 12BA x 4mm!

A 6mm dia head would indicate an M3 screw (tolerance 5.82 - 6.72) and that can only take a 2mm A/F hex socket.

Although 3.5 mm does appear in the list of metric threads it is non-preferred and there is no standard for Countersunk Socket Head Screws at 3.5mm dia.

The head height for a 6mm Ø C/snk is 1.86mm so 'N' couldn't possibly be 1mm.

I suspect that it is actually an M4 screw with a reduced head Ø. The Std for M4 is 7.78mm to 8.96mm Ø head, 2.48mm high with a 2.5mm A/F socket. Cutting that down to 6mm Ø would give 'N' = 1.4mm.

Flippsie has not mentioned the thread pitch - M4 is 0.7mm, M3 is 0.5 and 3.5mm would be 0.6.

The threaded part O/D of screws is seldom the full dimension but I would find 3.5mm for an M4 too small - it really depends on how accurately the screw has been measured - if it is with a Micrometer it ought to be good, with a steel rule close, a wooden rule or dress-makers tape forget it!

 

[NazNomad]

As you won't tell us what thread matched it, you'll have to contact the SiP technicians directly on 01509 500 376.

 

[Flippsie]

As you won't tell us what thread matched it, you'll have to contact the SiP technicians directly on 01509 500 376.

As I said before, SIP were my first port-of-call. My post on this forum was not in place of contacting the manufacturer first and inquiring after some spares. :roll:

 

[Phil Pascoe]

So did they tell you? Do you know? Go on, don't keep us in suspense - give us a clue.

 

[Flippsie]

There is a great deal wrong with those dimensions and I doubt that anyone would make them - I certainly wouldn't even try and I do make my own down to 12BA x 4mm!

A 6mm dia head would indicate an M3 screw (tolerance 5.82 - 6.72) and that can only take a 2mm A/F hex socket.

Although 3.5 mm does appear in the list of metric threads it is non-preferred and there is no standard for Countersunk Socket Head Screws at 3.5mm dia.

The head height for a 6mm Ø C/snk is 1.86mm so 'N' couldn't possibly be 1mm.

I suspect that it is actually an M4 screw with a reduced head Ø. The Std for M4 is 7.78mm to 8.96mm Ø head, 2.48mm high with a 2.5mm A/F socket. Cutting that down to 6mm Ø would give 'N' = 1.4mm.

Flippsie has not mentioned the thread pitch - M4 is 0.7mm, M3 is 0.5 and 3.5mm would be 0.6.

The threaded part O/D of screws is seldom the full dimension but I would find 3.5mm for an M4 too small - it really depends on how accurately the screw has been measured - if it is with a Micrometer it ought to be good, with a steel rule close, a wooden rule or dress-makers tape forget it!

Thanks for that detailed reply, you clearly know your threads. My question still stands however, where can I obtain some replacements?
Another member of this forum has confirmed for me that the thread is M4, but the head diameter is 6mm. I am going to have to buy some standard screws and grind the heads down.

 

[NazNomad]

Apparently, if you roll your eyes far enough into the back of your head, you can see your own ass.

See if these fit your agenda ... https://www.nbk1560.com/en/products/spe ... w/SNFS-SD/

 

[J-G]

First - apologies for the late reply - I've been busy on a Pascal project and not looked at this forum for a few days!

As far as suppliers go I can't point you to one like NazNomad with reduced head dia (though they seem to list only cross head rather than Hex-socket) but I would recommend Kay's Fasteners 01924 276555 - or search their eBay listings. They list M4 x 12mm A2 Stainless with 8mm Ø head at £1.15 for 10.

I ought to 'know my threads' as you put it - - - I spent a good few years as head of the threading dept. at Herbert Small Tools.

 

[woodpig]

It looks like it may be a M4 x 12mm countersunk socket screw with the head turned down a bit. If I have one "in stock" that size I could turn down the head for you.

Update: I have an M4 x 12mm CS socket screw. The head diameter is 7.86 mm but I can turn this down. The hex socket isn't 3mm though it's 2.5mm