Parkinson Vise Wobble

[steve355]

Hi

I have this old Parkinson woodworking vise, it’s a really heavy duty thing. However, across the last couple of years it seems to have developed a left to right wobble when I wind it in or out. I am sure that when I first got it, the jaws would be very parallel in their action.

I can’t see an obvious reason why, other than the guide rails or guides are worn. But I can’t believe that I have done that myself across the last few years. It could be that the half nut is full of crud. However, I’d rather get some advice before Tearing it to pieces!

 

[dannyr]

This is a fine old Parky, about 100 years +/- of the type that used a cast and machined way to slide and maintain parallel motion in and out. Later Records, Parkys and others used bars in drilled holes which means easier machining. The oldest of your type of quick release Parky (+/- 130 years old) was like yours but had a longer 'way' - in theory better, but all versions depend on accuracy of machining and all can wobble with wear (the bar-type may also loosen) and any can break.

I suppose in theory you could add some kind of shim, but does the wobble actually matter? When it's tight it's tight --- that's what counts.

The thread looks good from your photo - nut etc shouldn't anyway be a cause of this kind of wobble, but it's always good not to over-grease and to brush sawdust out of this area. Also check spring hasn't weakened over time (bit of a pain, but you can tighten).

 

[steve355]

This is a fine old Parky, about 100 years +/- of the type that used a cast and machined way to slide and maintain parallel motion in and out. Later Records, Parkys and others used bars in drilled holes which means easier machining. The oldest of your type of quick release Parky (+/- 130 years old) was like yours but had a longer 'way' - in theory better, but all versions depend on accuracy of machining and all can wobble with wear (the bar-type may also loosen) and any can break.

I suppose in theory you could add some kind of shim, but does the wobble actually matter? When it's tight it's tight --- that's what counts.

The thread looks good from your photo - nut etc shouldn't anyway be a cause of this kind of wobble, but it's always good not to over-grease and to brush sawdust out of this area. Also check spring hasn't weakened over time (bit of a pain, but you can tighten).

Interesting. I’m not sure the wobble does matter really. I just had it off the bench to put it on the new bench and I may as well fix anything I can while “in transit”. But looking at it this afternoon, I think it may be designed like that. The “ways” have a very pronounced taper - meaning the further out it is wound, the “wobblier“ it gets.

 

[Woodwork Journey Dean]

I restored my old Parkinson a while ago and had to bodge what I imagine were previous bodges on the quick release after one of the clamping bits broke.
I get very little left to right movement, but the bloody thing sticks constantly which means to unwind it I have to give it a whack every couple of turns.

Sorry for going off topic, feels good to vent about having to smack the vice a thousand times a day though LOL

 

[Johnwa]

Just for my own education, can someone more knowledgeable tell me what type of thread is on the main screw of this vise? I thought
I knew most thread types but I've never seen anything like that!
Sorry Steve355 for hijacking your thread

 

[steve355]

Just for my own education, can someone more knowledgeable tell me what type of thread is on the main screw of this vise? I thought
I knew most thread types but I've never seen anything like that!
Sorry Steve355 for hijacking your thread

Not at all, I find it as interesting as you. I think it’s a buttress thread. Normally one would expect a 29 deg ACME thread, but given the quick release it only really needs to be strong in one direction.

ACME thread and home ground cutter. Never cut a buttress thread!

 

[dannyr]

Yup, buttress thread - key part of the Parkinson's Perfect quick release patented 1880 and used since then by 99% of English-made QR vices, such as the Records.

Amazing how effective it is with just a half nut.

 

[J-G]

Just for my own education, can someone more knowledgeable tell me what type of thread is on the main screw of this vise? I thought
I knew most thread types but I've never seen anything like that!
Sorry Steve355 for hijacking your thread

Some good guesses but it is in fact an UNDERCUT Buttress Thread. Probably the most difficult thread to cut. When I was head of the Export Threading Department at Herbert Small Tools, I had an enquiry for a Coventry Diehead & Dies to cut such. No existing Diehead could handle it - Opening the dies at the end of the cut would jam the perpendicular retraction - so there was some intense design work needed to make the dies open at an angle. For some time I had the very first sample of a 1" x 8 5° undercut buttress thread cut with a Diehead sitting on my desk.

At the time this vice was made, the thread would be cut using a single point tool.

 

[steve355]

Some good guesses but it is in fact an UNDERCUT Buttress Thread. Probably the most difficult thread to cut. When I was head of the Export Threading Department at Herbert Small Tools, I had an enquiry for a Coventry Diehead & Dies to cut such. No existing Diehead could handle it - Opening the dies at the end of the cut would jam the perpendicular retraction - so there was some intense design work needed to make the dies open at an angle. For some time I had the very first sample of a 1" x 8 5° undercut buttress thread cut with a Diehead sitting on my desk.

At the time this vice was made, the thread would be cut using a single point tool.

That‘s really interesting. I had noticed the inward slope of the “flat” side of the thread and was wondering how that was done - I assumed on a lathe with a single point tool, but even grinding a bit with a clearance angle to make that work effectively would be tricky. The bit would have to come at the piece from a very acute angle, And the cuts would probably have to be shallow and slow. Else clogging and jamming hell - very little room for error too, it’d be a case of mess up once, chuck the blank away. Pretty natty piece of machining.

 

[dannyr]

Some good guesses but it is in fact an UNDERCUT Buttress Thread. Probably the most difficult thread to cut. When I was head of the Export Threading Department at Herbert Small Tools, I had an enquiry for a Coventry Diehead & Dies to cut such. No existing Diehead could handle it - Opening the dies at the end of the cut would jam the perpendicular retraction - so there was some intense design work needed to make the dies open at an angle. For some time I had the very first sample of a 1" x 8 5° undercut buttress thread cut with a Diehead sitting on my desk.

At the time this vice was made, the thread would be cut using a single point tool.

Interesting job and thanks for the details.

Of course at one time Herbert sold their own Ajax quick release buttress thread vices as well as similar Fortis vices from Coventry. So I suppose they had a serious production line the make the slightly lesser dia but considerably longer threads for these (or were they all sub-contracted to Coventry?). I assume a carbon steel was used - so straighten after cutting and heat treat?

 

[stuart little]

Hi

I have this old Parkinson woodworking vise, it’s a really heavy duty thing. However, across the last couple of years it seems to have developed a left to right wobble when I wind it in or out. I am sure that when I first got it, the jaws would be very parallel in their action.

I can’t see an obvious reason why, other than the guide rails or guides are worn. But I can’t believe that I have done that myself across the last few years. It could be that the half nut is full of crud. However, I’d rather get some advice before Tearing it to pieces!

View attachment 154951

Sounds like it's got Parkinsons! (No disrespect intended)

 

[J-G]

Interesting job and thanks for the details.

Of course at one time Herbert sold their own Ajax quick release buttress thread vices as well as similar Fortis vices from Coventry. So I suppose they had a serious production line the make the slightly lesser dia but considerably longer threads for these (or were they all sub-contracted to Coventry?). I assume a carbon steel was used - so straighten after cutting and heat treat?

I was never aware of Ajax or Fortis Vices being sold by Herberts, and (after a little research) see that the 'Ajax' brand appears to be a simple re-branding of a product made by Fortis. That wouldn't surprise me.

The commercial Export department at Herbert Small Tools was very 'compartmentalised' - with separate sections for Threading, Measuring, Work-holding, Microbore etc. I joined the Threading section but was eventually appointed Head of Department. As a 'Commercial' section we were office bound so seldom got to see the manufacturing side and as far as I am aware there was never a production section making Vice screws.

The 'sample' I had on my desk was simply produced to prove that the new design of the DieHead, along with 'Holozone' Dies, could do the job.