Boxford AUD Dickson QC post size?

[Cato]

Just a quick question on Dickson tool posts for a Boxford AUD.

Is a Dickson S0 too small as it says "up to 114 mm"? It seems that an S1 would be bang on the money at 114 to 127, and an S2 would just squeak in at 127 to 203?

Just trying to get my head round the set up side of things.

 

[Seadog]

Dickson Quick-set Toolholders

How the lathe works. Names of lathe parts. Screwcutting. Generating changewheel charts. countershafts. backgears. tumble reverse. Stuck chucks. Quick-change toolposts. Fitting a chuck Spindle nose fittings, backplates, Oiling

www.lathes.co.uk

Quick Change Tool Post - Dixon Type - ABM Tools

Quick Change Tool Post - Dixon Type ABM Tools

www.abmtools.com

 

[Cato]

I read through the stuff on Lathes.co.uk (great site for info). It was more a question on what's right? and if the S0 'will do'?

So the S0 will work with tools set at max height and/or spaced? S1 is the sweet spot which will work with most tools? S2 is OK but you'll struggle sometimes with tools that don't go quite low enough to centre? That sort of thing.

 

[Agroshield]

Your original question is asking about centre height. There is another factor to consider: the shank size of the cutting tool you have or want to use.

In practice, the numbers above give a minimum centre height for each size (you could use an S0 on a lathe with 15" centre height, but if it only held 8mm shank tools, your cutting capacity would be limited).

Bigger holders are also more expensive when you need extras. As it is a free market, the most popular size will be the cheapest, so in hobby lathes, that generally means Myford-size (12mm shank tools, I think, but please check).

 

[Cato]

Your original question is asking about centre height.

It wasn't, the question (and thread title) is about Dickson tool post sizing. Dickson base their posts on centre heights and I wanted to know from those more experienced whether it was better to have a post below, at, or with the capability to go above the centre height. i.e. Which of their range of tool posts is the most suitable.

In practice, the numbers above give a minimum centre height for each size (you could use an S0 on a lathe with 15" centre height, but if it only held 8mm shank tools, your cutting capacity would be limited).

In this example, how would you be able to get the tool height to the lathe centre height? If you can only get to 114 mm via post/holder adjustment, and maybe a few mm more with a little tilting of the tool in the holder that still leaves you a long way below centre?

 

[Seadog]

Off the top of my head (I will check when I get home) the centre height from the top face of the compound is 63mm.

 

[Cato]

Off the top of my head (I will check when I get home) the centre height from the top face of the compound is 63mm.

Maybe it's a terminology issue then? I mean me using the wrong one BTW. I was working on the centre height from the bed being 5" - 127 mm.

So for a Dickson S1 I was viewing it as that being suitable for a lathe centre height of between 114 and 127 mm from the bed, and an S2 being suitable for a centre height of 127 mm and up? Working on that (possibly incorrect) arrangement my question was would it be better to have the flexibility for adjustment above or below the centre height.

 

[Arc Tourist]

I have a 4 1/2 inch swing Boxford lathe, and the proper Dickson tool post holder is the 51mm height " S.O. " Model.

 

[Seadog]

The centre height to the top of the compound is 25mm and 65mm to the cross-slide.

 

[Agroshield]

It wasn't, the question (and thread title) is about Dickson tool post sizing.

In this example, how would you be able to get the tool height to the lathe centre height? If you can only get to 114 mm via post/holder adjustment, and maybe a few mm more with a little tilting of the tool in the holder that still leaves you a long way below centre?

Sorry, I mis-spoke. Let me say more precisely that your original question is only framed in terms of centre height. You need to add into the mix the tool size that you have or want to use.

The Dickson tool post specifications are given in terms of (minimum) machine centre height that a particular model (S0, S1, S2) will fit. So what they are saying is that if you put an S2 on a machine with a 114mm centre height, you will never get the tool low enough to be on centre. The other way is never a problem: if you fit a small toolpost to a large lathe, you put a spacer under the toolpost to bring the tool up to centre.

I hope you have grasped the point about tool sizing. If you happen to have a load of 10mm shank tools but buy a toolpost that takes 16mm shank tools, you will have to shim every single tool individually to get it high enough. In the case of you having tools of a certain size, it would be better to buy a toolpost to suit them and space the whole toolpost up once and for ever.

As you correctly say, centre height is specified as 'above the bed'. Other, related sizing measures are 'swing over bed' (Arc Tourist) and 'swing over cross-slide', with the added complication that sometimes these latter two are in radius (Arc Tourist), sometimes in diameter.

 

[Agroshield]

The centre height to the top of the compound is 25mm and 65mm to the cross-slide.

I think what he is trying to reconcile is the considerable size difference between your numbers and the numbers in the original post - neither is lying, so it means that they are measured from different places. Would you agree that the Dickson ones are 'centre height above bed'?

 

[Cato]

Sorry, I mis-spoke. Let me say more precisely that your original question is only framed in terms of centre height. You need to add into the mix the tool size that you have or want to use.

The Dickson tool post specifications are given in terms of (minimum) machine centre height that a particular model (S0, S1, S2) will fit. So what they are saying is that if you put an S2 on a machine with a 114mm centre height, you will never get the tool low enough to be on centre. The other way is never a problem: if you fit a small toolpost to a large lathe, you put a spacer under the toolpost to bring the tool up to centre.

I hope you have grasped the point about tool sizing. If you happen to have a load of 10mm shank tools but buy a toolpost that takes 16mm shank tools, you will have to shim every single tool individually to get it high enough. In the case of you having tools of a certain size, it would be better to buy a toolpost to suit them and space the whole toolpost up once and for ever.

As you correctly say, centre height is specified as 'above the bed'. Other, related sizing measures are 'swing over bed' (Arc Tourist) and 'swing over cross-slide', with the added complication that sometimes these latter two are in radius (Arc Tourist), sometimes in diameter.

Ah right, I get you now. Yes I saw the tool shank size issue/requirement, but the way the post heights were described was throwing me a bit. So you can 'lift' a shorter post but not drop a taller one which makes sense. Ideally then an S1 would be the ideal but an S0 will work for most things.

 

[Seadog]

Yes, I'd agree with that. However, you really do need to look at the dimensions of the block and just where you can get the centre of the tool to sit. It's not so clear cut.
If you remove the compound then you can use a larger toolpost, and vice versa.

 

[Seadog]

So you can 'lift' a shorter post but not drop a taller one which makes sense.

That depends. If the toolpost is positioned to the left of the compound, and the compound is set to plunge, then you can drop the edge of the toolholder below the level of the compound.

 

[Cato]

That depends. If the toolpost is positioned to the left of the compound, and the compound is set to plunge, then you can drop the edge of the toolholder below the level of the compound.

Just for clarity, by 'compound' are you referring to the top face of the top (x axis?) slide?

 

[Seadog]

The compound slide top surface. (Also sometimes called, incorrectly, The Top Slide).

 

[Cato]

The compound slide top surface. (Also sometimes called, incorrectly, The Top Slide).

I guess as with any trade or discipline half the battle is deciphering the language made up of the technically accurate, slang, abbreviations, inaccurate descriptions and acronyms. Especially when you add on the regional variations and manufacturer/brand names that become descriptions.

 

[ukracer]

Just think your self lucky @doubleboost has not found this thread and posted a video.

 

[Cato]

Just think your self lucky @doubleboost has not found this thread and posted a video.

I've been watching some of his stuff on YouTube, they're good, informative and unlike a lot of the technical/how to type stuff on there he doesn't sound like Troy McClure or Ted Kaczynski.

 

[ukracer]

I've been watching some of his stuff on YouTube, they're good, informative and unlike a lot of the technical/how to type stuff on there he doesn't sound like Troy McClure or Ted Kaczynski.

We have Google translate going on a Sunday night. Lol