Fox 5/8" Mortiser Problem - HELP Please!

[OPJ]

Hi guys,

I've got the Fox 5/8" Mortiser with rotating headstock from Rutlands (this one here). It's a couple of years old, maybe, and I haven't had a problem with it until now, right in the middle of my workbench build.

I'll try to explain this as best as I can but, what I'm finding is that the plunge lever can be rotated a good 5-10° before it engages with the gear that drives the head up or down. I'm not talking about the 'slop' in the fit of the lever. I've been mortising 70mm beech with a ½" Japanese chisel and it suddenly 'went' this evening... It seemed fine on Tuesday. I'm not getting the same feel of applying pressure in the cut that I was getting before.

This lot still fits nicely. Nothing appears to have worn away here.

Can you see the roll pin(?) below?

I've noticed this seems to be sticking out; it may or may not have been doing that since I bought the machine anyway. :? But, when I punch this back inside, it seems to cure my problem temporarily - until I plunge the lever, at which points it forces it's way out! :roll: You probably can't see this in the photo but, only half the pin is visible (it could be broken?).

This is how things look inside. [Sorry, I should've rotated the photo 90° to the anti-clockwise! ]

Both screws are done up dead tight and, as you can see, there's plenty of grease on the gear mechanism.

The problem seems to lie somewhere in the relationship between the gear and the lever mechanism... Not surprisingly, the supplied manual isn't a lot of help, only telling me what I already know, in that part number 32 is, indeed, a pin... :roll: Don't know what Hamilton are like for technical help either.

Has anyone seen anything like this before? Any thoughts? I think it might be worth trying to remove the pin and then fitting a replacement.

Thanks for looking.

 

[9fingers]

Olly,

I can only think that the rollpin has broken; otherwise I can't see how normal operation can eject the pin.

I suggest you remove it and try and get a new one.

Good Luck

Bob

 

[OPJ]

Thanks, Bob, I'm glad we're thinking along similar lines, here!

I'll have a go at that tomorrow and see what happens.

 

[Travis]

I second the idea of a new roll pin. 8) 8)

Travis

 

[Tony Spear]

If you are going to replace the pin, don't try and remove it before fitting the new one as you may have problems aligning the holes. Tap the current pin in far enough to enable you to locate the new pin and then drive in the new pin, using it to drive the old one out as it goes in.

 

[TheTiddles]

Definietly the roll-pin, if it's a through hole or has a knock-out bore then I'd fit a proper dowel pin which should last much better, if you haven't got a stock of pins then consider reaming it through and using a bolt

Aidan

 

[newt]

Olly some roll pins are tapered (unlikley in you case) so watch for this. If it is broken in half you may only be able to extract one half, this should not be a problem as you can slide off the outer part and inspect all the holes to check they are clear. The roll pin is designed to shear at a certain load, however they must be tight in each component to work as designed.

 

[newt]

Olly just had a thought, if you have a problem punching out the old pin, you could remove the whole assembly. If it is like mine the securing bolts that hold the pinion can be released and the shaft slid out of the pinion.

 

[9fingers]

I'm wondering what on earth the roll pin is there for?

With the amount of leverage on a morticer, surely the roll pin would be nothing like strong enough. My morticer - a square column Axi one - has that shaft all in one piece.

There must be something else to transmit the forces.

Bob

 

[Anonymous]

I have a number of Fox machines and all have had to have modifications in their lives. Telephone Hamilton Tools for advice first instance.

01206 798600 [email protected]

Koolwabbit

 

[newt]

Bob, yes a roll pin does make you think. However mine has one and the hole is 5.6mm, I guess for a 6mm roll pin. I like Bob am surprised that a roll pin of this size can support that amount of torque ( Olly may have proved otherwise).

 

[maltrout512]

OPJ you can if you want to insert an new role pin and then insert a role pin in the role pin. If you see what I mean. Role pins differ in hardness and are used as shere pins in certain machinery where protection of overload is required.

 

[9fingers]

6mm roll pins have a shear strength of between 1700 and 5000 lbs and a solid pin ( somewhat surprisingly only ) 6000lbs

about 800, 2300 and 2700 kgs respectively.

Assuming a 60:1 mechanical advantage (600mm bar, 20mm diameter at the shear surface) then the pins would shear at 13kg, 38kg and 45kg,

This seems a very under specified pin unless they have an awareness that the gearing is weak and so are trying to protect the teeth.

Bob

 

[TheTiddles]

6mm roll pins have a shear strength of between 1700 and 5000 lbs and a solid pin ( somewhat surprisingly only ) 6000lbs

about 800, 2300 and 2700 kgs respectively.

Assuming a 60:1 mechanical advantage (600mm bar, 20mm diameter at the shear surface) then the pins would shear at 13kg, 38kg and 45kg,

This seems a very under specified pin unless they have an awareness that the gearing is weak and so are trying to protect the teeth.

Bob

That's the level of answer you get from a retired person!

Aidan

 

[Digit]

Interesting point there Bob, when I first met up with roll pins they were specifically there as 'shear' pins, designed to protect other parts from damage.
It's only recently that they seem to have been taken up as a quick assembly feature.

Roy.

 

[9fingers]

6mm roll pins have a shear strength of between 1700 and 5000 lbs and a solid pin ( somewhat surprisingly only ) 6000lbs

about 800, 2300 and 2700 kgs respectively.

Assuming a 60:1 mechanical advantage (600mm bar, 20mm diameter at the shear surface) then the pins would shear at 13kg, 38kg and 45kg,

This seems a very under specified pin unless they have an awareness that the gearing is weak and so are trying to protect the teeth.

Bob

That's the level of answer you get from a retired person!

Aidan

Possibly true Aidan!

Yes guilty as charged, newly retired and loving it! That reply as it happens was a couple of minutes with Machinery's Handbook and another couple of minutes of one-handed typing whilst munching on a lunchtime sarny in the other.
It is also a reply from an ex researcher with an enquiring mind - I still just HAVE to know why things are as they are.
I guess it will be that way until I'm reduced to a single marble; hopefully in a very long time from now.

Much get back to having fun in the workshop now- I suppose you are still working at this time of day :lol:

Bob

 

[newt]

Bob, cant see any data on tapered roll pins, therefore it can be assumed they do not exist, and that Olly's must be parallel. The ones I was thinking of had a small taper to help with the initial entry.

 

[9fingers]

The roll pins I am familiar with have a small chamfer on both ends for the purpose of giving a lead in and compressing the spring.
I've only used solid taper pins which are rather out of day these days as are the tapered reamers to match. They go back to the days of hand fitters with skills!

Cheers

Bob

 

[Yetty]

The pin on my Fox mortiser (same model) also sheared, surprisingly quickly.
When replaced with a M6 bolt (stainless as it happens, so weaker than 8.8 mild?) this soon also sheared.
Currently using a length of M6 drill bit, so far so good!

 

[OPJ]

Thanks to everyone for their thoughts - as usual, you've given me plenty to think about!!

I managed to just about complete my last batch of mortising this morning without having replaced the pin... Now though, I'm a little confused as to whether or not I should try using a solid pin, in case (as Aidan suggested) it does eventually knacker the gear?

Then again, a pack of roll pins won't cost much. I could always keep plenty spare and replace them as and when required.