Parkinson Perfect Vice

[Crispym]

That restoration looks lovely. I've just embarked on my own Mk II restore but I've mullered the slot of the small screw holding the quick release bar to the qr lever rod. I think I'm going to have to drill it out so does anyone know what size screw I'll need to replace it with? Thanks in advance.

 

[kinverkid]

I've just picked up an Parkinson Perfect Vise, USA No.4 plane, apple peeler, Blow-lamp, three sickles, car jack and real nice Oden? bench dog from Freecycle. Only went for the vise, the other stuff were bonus items.

 

[Garden Shed Projects]

Where is this free cycle? It looks like you have some amazing finds there. Can I assume you have not got them for free?

 

[Garden Shed Projects]

That restoration looks lovely. I've just embarked on my own Mk II restore but I've mullered the slot of the small screw holding the quick release bar to the qr lever rod. I think I'm going to have to drill it out so does anyone know what size screw I'll need to replace it with? Thanks in advance.

I am not sure I can help. If I removed the screw I would have no way of knowing what thread it is.

 

[kinverkid]

Where is this free cycle? It looks like you have some amazing finds there. Can I assume you have not got them for free?

Yes. Free! It's a stipulation of the site Freecycle that anything you are getting rid of must be free to the collector.

Gary

 

[Vono]

Some great work on this thread.
Parkinsons really did produce quality kit.
Here's my No16.

 

[Crispym]

I am not sure I can help. If I removed the screw I would have no way of knowing what thread it is.

I know what you mean - I have a missing bolt on the half-nut and a bent one on the runner back plate. I did a crash bit of research into imperial bolt sizes and found there are two main thread types: fine (UNF) and coarse (UNC) determined by the major diameter (the distance from the outer thread on one side to the outer thread on the other side). By measuring the major diameter and counting the number of threads in 10 mm (8), I determined that my missing bolts were 1/4" UNC with 20 tpi and were 3/4" long (the threaded part). This site was very useful: UNC Thread ANSI/ASME B1.1

The screw I'm looking for appears to be 1/2" long and possibly 3/16 (~4.7mm) major diameter (but that's with the screw still seized in position). If it is 3/16 then I think that would be a #10-24 screw with 24 tpi. If it's smaller than that then we're looking at the #8 with 32tpi.

Really grateful if you can help.

 

[dickm]

Would be surprised if the bolts were Unified. At that period, would expect them to be Whitworth or BSF; sometimes these sizes match with Unified ones, but only rarely. And, of course, if you go to smaller stuff, you've got British Association (BA) or some wondrous strange cycle ones!

 

[TominDales]

That restoration looks lovely. I've just embarked on my own Mk II restore but I've mullered the slot of the small screw holding the quick release bar to the qr lever rod. I think I'm going to have to drill it out so does anyone know what size screw I'll need to replace it with? Thanks in advance.

By MK II I presume you mean the one with the round bars. Although I both MKs, the later was missing the rod so I had to make one. I'll measure the screw on the MKI and let you know. They are imperial sizes so likely to be 1/4''. on my MkII I board 6mm with a tread cutter - tap and die set. I'll measure the MK1 tonight and let you know.

 

[Crispym]

By MK II I presume you mean the one with the round bars. Although I both MKs, the later was missing the rod so I had to make one. I'll measure the screw on the MKI and let you know. They are imperial sizes so likely to be 1/4''. on my MkII I board 6mm with a tread cutter - tap and die set. I'll measure the MK1 tonight and let you know.

My one has cast sliders, two screw holes on the front face and the shorter fixed undercarriage. I looked at the smallworkshop.co.uk history and figured it was the Mk II. However, I'm sure the little qr plate securing screw will be the same between the different versions. Thanks very much for helping.

Would be surprised if the bolts were Unified. At that period, would expect them to be Whitworth or BSF; sometimes these sizes match with Unified ones, but only rarely. And, of course, if you go to smaller stuff, you've got British Association (BA) or some wondrous strange cycle ones!

Oh lawks - and I thought I was doing so well working out about Unifieds (like I said, crash course )! Of course, this is why one comes to a site like this: to draw upon others' superior knowledge, so thank you.
I'll look into those other standards but I actually bought a couple of 1/4"-20 UNC bolts which appear to fit so I might have got lucky there. What I don't like is having to replace the bolts with shiny hex head ones though - I know they won't normally be seen but it jars with my sense of the age of the thing. I did find some square head ones (UNC bien sur) from a site in the US for only a couple of dollars: 'Nice' I thought until I saw the $48 shipping charge! I'll keep looking.

 

[TominDales]

My one has cast sliders, two screw holes on the front face and the shorter fixed undercarriage. I looked at the smallworkshop.co.uk history and figured it was the Mk II. However, I'm sure the little qr plate securing screw will be the same between the different versions. Thanks very much for helping.

I'm assuming the screw is the one holding the bar into the spring. see the photo, I loosed mine, not a great picture as the garage door was left open and its under the bench and lots of dust!.
The screw came out very easily, given I bought it off my Latin teacher 45 years ago and he was reluctant to part with it at it was his fathers, I presume its about 90 odd years old! The dimensions are 4.7mm diameter and ca 0.7mm pitch. I therefore think its:
BSF 3/16 inch that is British standard fine 3/16 inch. The BSW equivalent 3/16 has a 1mm pitch, this seems nearer 0.7mm and it looks like a fine pitch. The BSF dimensions are 4.82mm and 32 thread per inch which is 0.8mm. So within the margins of measuring this looks like the one.
, The thread looks fine pitch, it almost easier to tell the difference in pitch by eye than by using the caliper!

PS I'm now a bit confused over the MKs, The one I've photographed has the cast bars and it has 3 screw hole in the front, so its probably a MkII? from the catalogues? I think I mentioend my more modern Parki with the steel bars did not have the original bar and spring.

 

[dickm]

Not superior knowledge, but access to my oil-stained Zeus chart (ye gods, the typeface is tiny! Or has my eyesight got worse?) suggests:-
If the screws are 1/4 inch OD, then as you've found there is 1/4 20 UNC, which has 20 tpi (for the metric only folks, that's a bit more than 1mm pitch.)
In BSF, 1/4 inch OD is 26tpi, which is darn close to 1mm pitch.
Interestingly, 1/4 BSW is 20 tpi, the same as the UNC you've got.
Not sure what head shape is needed, but if it's 1/4BSW, there's a variety in my tobacco tin full, so could possibly match what you need.

 

[TominDales]

Not superior knowledge, but access to my oil-stained Zeus chart (ye gods, the typeface is tiny! Or has my eyesight got worse?) suggests:-
If the screws are 1/4 inch OD, then as you've found there is 1/4 20 UNC, which has 20 tpi (for the metric only folks, that's a bit more than 1mm pitch.)
In BSF, 1/4 inch OD is 26tpi, which is darn close to 1mm pitch.
Interestingly, 1/4 BSW is 20 tpi, the same as the UNC you've got.
Not sure what head shape is needed, but if it's 1/4BSW, there's a variety in my tobacco tin full, so could possibly match what you need.

I've measured my old MKII and pretty sure it 3/16 BSF, the screw is in perfect - mint condition amazing given its likely to be 100 years old, but then it never needs to be used. It has good oil on it, so I suspect I re-oiled it in 1975!

I think if @cryspym finds he has a damaged thread it would be simplest to re-tap it. I've had a number of old tools with 3/16 and 1/4 bs(w/f) and generally re-tapped with M5 or M6 when the treads have been a bit worn, probably M5 in this case. This screw is only loosed when the spring breaks, which must by a once in 50 year operation!

 

[dickm]

What I don't like is having to replace the bolts with shiny hex head ones though - I know they won't normally be seen but it jars with my sense of the age of the thing. I did find some square head ones (UNC bien sur)

Going back to you original post, you said you had mullered the SLOT in the original bolt. This suggests it may have been a countersunk head, 1/4Whit set screw. Or did it have a square head as you suggest later? If you can confirm, it's quite possible there is one in my magic box. Let me know.

 

[Crispym]

So gratified by the helpful comments here and the offers from excellent baccy tins!

The screw came out very easily, given I bought it off my Latin teacher 45 years ago and he was reluctant to part with it at it was his fathers, I presume its about 90 odd years old! The dimensions are 4.7mm diameter and ca 0.7mm pitch. I therefore think its:
BSF 3/16 inch that is British standard fine 3/16 inch. The BSW equivalent 3/16 has a 1mm pitch, this seems nearer 0.7mm and it looks like a fine pitch. The BSF dimensions are 4.82mm and 32 thread per inch which is 0.8mm. So within the margins of measuring this looks like the one.

I think if @cryspym finds he has a damaged thread it would be simplest to re-tap it. I've had a number of old tools with 3/16 and 1/4 bs(w/f) and generally re-tapped with M5 or M6 when the treads have been a bit worn, probably M5 in this case. This screw is only loosed when the spring breaks, which must by a once in 50 year operation!

Thanks for that information @TominDales . I haven't removed the screw yet but I've just bought some Deep Creep to see if that loosens things. I'll also see if I can find a BSF 3/16 but will be keeping my M5 tap ready just in case.

Going back to you original post, you said you had mullered the SLOT in the original bolt. This suggests it may have been a countersunk head, 1/4Whit set screw. Or did it have a square head as you suggest later? If you can confirm, it's quite possible there is one in my magic box. Let me know.

Yes, slot I'm looking at trying to remove the slotted screw from the qr bar, as seen in @TominDales pic, which seems to be not wanting to go anywhere any time soon - hence the mulleration.
However, I also have a missing 1/4" square-head bolt that secures the saddle over the half-nut and another from the plate attached to the end of the sliders which is bent (the bolt, not the plate). They're definitely 20tpi. If your baccy tin can be persuaded...

 

[Crispym]

After a conversation with @dickm I thought I would try grinding the hex-head bolt to a square head.

Here's the original (with the bent one as well).

All in all, I don't think it came out too badly and the, er, heat treatment from the grinding wheel has discoloured the bright steel of the new bolt so it tones in a little bit with the old.

Now, the qr bar screw appears to be well and truly seized. Not sure of the best way to deal with it so any suggestions?

 

[dickm]

Looks a super job, crispym. Bit of judicious rusting and noone would ever know!
As for the seized screw, it sounds like you are getting towards the "drill it out and pick out the bits" stage. I guess you've tried localised heating then sudden cooling and all the proprietory seize releasers? Was going to suggest blowlamp followed by one of those plumbers' pipe-freezing sprays, but since it goes into a casting, that might be a bit too fierce.

 

[TominDales]

After a conversation with @dickm I thought I would try grinding the hex-head bolt to a square head.

Here's the original (with the bent one as well).


Now, the qr bar screw appears to be well and truly seized. Not sure of the best way to deal with it so any suggestions?

Its coming on nicely. Good reproduction.
I agree with DickM, time to drill it out and pull out the bits. if you have one of th You will then have to tap to a slightly bigger size. Suggest you go metric at M5 (depending on how well it drills out) or up to M6.

 

[Crispym]

Drill and pick was the conclusion I was coming to but hadn't thought of @dickm's suggestion of heat treatment. As they say, I won't try the heat/freeze but I'm sure a bit of judicious heat won't go amiss. Stay tuned

BTW, tried the new bolt in place and it looks fab!

 

[Crispym]

Well hurrah. Mission accomplished!

Didn't bother with heating and went straight to drilling and got it clear. Managed to go through 3 drill bits mind - pressing too hard I imagine.
Additionally, very happy to report that the UNC 10-24 screws I (optimistically ) ordered actually fit!

Next challenge is drilling out a seized 5/16 BSW screw (getting wise to these threads now, heh) from the front plate that was holding the wood face on.
Then I can start cleaning the whole thing up.

BTW, the back face isn't broken - it's just a fold of the plastic sheet!