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View Full Version : Camlock stud cutout radii? (was - is there a correct way?)



Timleech
01-31-2010, 03:17 PM
Tim,
I have done a fair bit of work on D1-3 studs and have full engineering drawings.
I have found out that a lot of what's there isn't needed.
Those side radii are not always needed and it depends on the type of cam fitted.


http://www.stevenson-engineers.co.uk/files/D1-3a%20camlock%20stud.jpg

If the side radii are omitted and the sides flatted off they fit and work fine.
What is critical is the diameter of the main cutout and it's position.

.

John (or anyone)

I've just made 18 threaded blanks for D1-8 metric studs, just (!) have to cut the radius and locking groove now, still working out how I'll go about it. The sample I'm working from has a main cutout of apparently 1.125" diameter, but this is 'feathered off' towards the free end of the pin. Is this common/essential/unnecessary? I haven't seen any D1-8 pins with that side radius shown in your drawing, but some of my D1-3 have it

Thanks
Tim

Black_Moons
01-31-2010, 04:24 PM
Iv seen a sorta side radius on my pins, but that was due to giant maring when the chuck came partialy loose during a parting operation..

Hate to hijack, but what is the radius 'stud cuttout radii' for D1-4 or a D1-X pin chart to awnser both the OP's and my question? :)

John Stevenson
01-31-2010, 07:15 PM
Get a lump of square or hex, belt a thread in it to match the studs, bung it in the mill vise with the new pin sticking out. Lob a 1 1/4" end mill or shell mill in the spindle and with it positioned with the DRO [ use an existing stud as a position setup ]

Support the sticky out end on a packed up vee block and clamp it down so it can't unscrew. plunge feed the cutter.

You may need to do a couple of passes with a 1 1/4" cutter.

Swap to another pin and do that.

Timleech
02-01-2010, 05:12 AM
Get a lump of square or hex, belt a thread in it to match the studs, bung it in the mill vise with the new pin sticking out. Lob a 1 1/4" end mill or shell mill in the spindle and with it positioned with the DRO [ use an existing stud as a position setup ]

Support the sticky out end on a packed up vee block and clamp it down so it can't unscrew. plunge feed the cutter.

You may need to do a couple of passes with a 1 1/4" cutter.

Swap to another pin and do that.

I'd got something along those lines in my head, I've centre drilled the outer end of the pins specifically so that supporting them with dividing head tailstock is an option - could even have the threaded support in the DH chuck, but I'm thinking of trying to arrange cutting the locking groove in the same setup.
Doesn't answer my question though - is a purely circular cutout OK, the ones I'm working from have it opened out a bit at the free end? I'll have to check with some others.

Tim

John Stevenson
02-01-2010, 05:24 AM
Tim,
Only worked on D1-3's and these were circular, even bought a set from J&L in the first place but found that they were available in UNF and metric and I wanted BSF,....... typical, hence making some.

I took the drawings from a brand new set and on the D1-3 a slug of 0.750" steel was a perfect fit.

Could the 'taper' be wear ? Because it's the free end that takes the grunt.

Timleech
02-01-2010, 05:47 AM
Tim,
Only worked on D1-3's and these were circular, even bought a set from J&L in the first place but found that they were available in UNF and metric and I wanted BSF,....... typical, hence making some.

I took the drawings from a brand new set and on the D1-3 a slug of 0.750" steel was a perfect fit.

Could the 'taper' be wear ? Because it's the free end that takes the grunt.

No it's not wear, it starts roughly at the (visibly abraded) contact point with the cam and continues to the end of the cutout. Those are on a catchplate, I'll take some off a chuck to compare.

Thanks
Tim

Timleech
02-01-2010, 06:34 PM
I've checked some brand new D1-11 (P-BI brand) pins tonight, they show the same 'fairing off' at the free end of the cutout. Thinking very roughly about the geometry, in my head, I wonder if it makes the locking more secure as the cam is bearing on a slightly reduced 'angle'?
I'll make them initially with the purely circular section cutout and see how well they work.

Tim

John Stevenson
02-01-2010, 06:52 PM
Tim,
Those pins I gave you that are for a smaller fixing, are they tapered as well ?

I only have about 6 or 7 sets of D1-3 here, nothing else on camlocks so i can't check.

.

Timleech
02-01-2010, 06:56 PM
Tim,
Those pins I gave you that are for a smaller fixing, are they tapered as well ?

I only have about 6 or 7 sets of D1-3 here, nothing else on camlocks so i can't check.

.

I'll have a look tomorrow. It's dark & wet out there at the moment !

Tim

John Stevenson
02-01-2010, 07:02 PM
What about being haunted ?

.

Timleech
02-01-2010, 07:13 PM
What about being haunted ?

.

I've just been out to get some coal in, it's cold, dark, raining, with snow on the ground. That's enough without worrying about ghoulies & ghosties ;)

Tim

John Stevenson
02-01-2010, 07:16 PM
Is your bath still outside then ?

.

JCHannum
02-01-2010, 08:38 PM
An assortment of D1 pins of variuos sizes and manufacture are about half & half with and without the taper on the free end. It seems to favor the larger sizes, maybe to assist in camming a heavy chuck into place?

Timleech
02-02-2010, 05:26 PM
An assortment of D1 pins of various sizes and manufacture are about half & half with and without the taper on the free end. It seems to favor the larger sizes, maybe to assist in camming a heavy chuck into place?

I've checked through some others, most seem to have it but in varying degrees as though it's a sort of ad hoc addition to the original spec.

I wonder whether the extra side radii are there to make sure the cam sits square against the pin to save wearing the pin? If the pin was full width at the bearing surface, there would be more chance of it bearing just on the edge? Just a thought, can't see any other reason for it, but also I've only seen it on, I think, D1-3.

I finished three pins and tested them on a backplate in the lathe, seemed to work OK so I've finished the rest

http://i559.photobucket.com/albums/ss38/Timleech_2009/DSCF2905.jpg

Second from the right is a commercial, Unified threaded item and you can see the extended cutout at the top.

Metric D1-8 pins have an M20 x 1.5 thread, I was dead lucky to find that I had die head chasers and a tap for that thread, it would have been a lot more work without.

http://i559.photobucket.com/albums/ss38/Timleech_2009/DSCF2899.jpg

I tapped a thread in a redundant cast iron engine mount, screwed the blanks in with a sacrificial spacer & supported the end just by wedging a vee block in place. Was able to do the main cutout and the locking groove in one setup, having DRO on all 4 axes made it a lot easier.
The only 1.125" cutter I could find is a clapped out, freehand sharpened, slot drill but it did the job. The ball end cutter for the locking grooves wasn't much better!

http://i559.photobucket.com/albums/ss38/Timleech_2009/DSCF2901.jpg

http://i559.photobucket.com/albums/ss38/Timleech_2009/DSCF2902.jpg

I wanted two sets (12) pins, but decided to make 18 'just in case', easier now than having to set up again in the future.
material is 1" dia bright EN8 (4140??)
A lot of work, don't know whether I would bother again especially as I've now found a dealer who sells secondhand pins (for about 2/3 the price of new ones!), but hopefully I'll never need any more.

Tim

Timleech
02-02-2010, 05:27 PM
Is your bath still outside then ?

.


Ho, Ho, Ho :D :D

Tim