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"Clog" toolpost- replace?

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William Ayerst30/10/2020 10:02:39
58 forum posts

Good morning gents, I've been sorting through the Ml7 parts that I've got stashed around pending it being reassembled on my new bench, and I was wondering - I've got a clog-style toolpost with the big clamp straight onto the topslide. In 'The Amateur's Lathe' the gent recommends this as a good start, but could potentially damage the topslide surface and so a more modern equivalent with a millled slot or what I'd know as a four-way toolpost is recommended.

I have three double-ended 1/2" HSS tool bits that have been ground by someone on a grinding wheel - indeterminate quality. I don't have a grinder myself (yet). Not wishing to cause potential wear on the lathe I've just bought, I am thinking that it makes sense to buy a new toolpost that clamps on the turret instead of the topslide.

I'm not overly fussed about a few minutes to spin a toolpost around so I'm not sure I need a quick-change variant, but if I could get any recommendations for what to buy - or indeed whether to stick with the original - I would be very glad to hear them.

Edited By William Ayerst on 30/10/2020 10:18:59

JohnF30/10/2020 10:16:20
1026 forum posts
143 photos

Hi William, not quite sure what you mean by "clog type" tool post unless its the triangular single clamp that was supplied originally ?

However you mention a quick change system, personally I would go for the Dickson type, I have been using these since they first appeared in the 1960's I have them on all my lathes in appropriate sizes. Now you can only purchase clones but if you buy from a well known reputable supplier, Myford, RDG, Chronos etc and continue to buy any additional holders from the same source you should be OK.

There are other designs available and one that seems to have a good reputation are those sold by Arceuro -see the ad herein.

On all of these you will need to use a smaller took bit 3/8" or 10mm square HSS is a good start.


William Ayerst30/10/2020 10:45:53
58 forum posts

Yes, sorry - the one that's a big triangular clamp.

Is there any meaningful quality difference between the RDG and Myford-branded dickson-style toolposts? It looks very, very similar but the Myford one is >£50 more expensive. Is this just because it has the correct badge, or is it made differently/better?

Thank you!

Howard Lewis30/10/2020 10:55:58
3757 forum posts
3 photos

Firstly, I am puzzled by the reference to a toolpost on the Turret rather than the Top Slide.

I would have thought that for most work, having a toolpost on the Top Slide would be an advantage.

A four way toolpost takes barely a second or two to reposition, and will carry three tools, so is an immense improvement on the standard tool clamping arrangement.

Others will champion a Quick Change Toolpost. Ideal if you are often changing a lot of tools, and have the space to store all the holders. (And the cash to buy them ) An advantage is that the tools are already set to centre height, without the need for packing or shims..

Since I have both front and rear 4 way toolposts on my larger lathe (My ML7 had a single back toolpost for parting off and a fourway for all other work   six tools are available very quickly. Changing over for screwcutting or knurling is slower, but not being on piecework, time is rarely of the essence..



William Ayerst30/10/2020 11:07:15
58 forum posts

Sorry, I meant that a tool post with a four-way slot/etc. would be clamping the tool into the turrent, rather than clamping the tool against the topslide.

Hopper30/10/2020 11:12:59
4868 forum posts
105 photos

All I use is the 4-way. RDG sells one for 24 quid that would get you going.

Howard Lewis30/10/2020 11:17:52
3757 forum posts
3 photos

Having made up a Centre Height Gauge, the tools have packers and shims inserted under them to bring the cutting edge up to centre height. (Most food tins seem to made from tinned steel which is 0.010" (0.254 mm ) thick.

Drink cans are Aluminium, which eventual crushes under load..

Ideally a solid packer, with as few shims as possible for the final adjustment.

Very fine adjustment can be obtained by varying, slightly, the torque applied to the clamp screws.

There are a variety of Q C Toolposts on the market, but I gather that holders are necessarily interchangeable between marques.


Dave Halford30/10/2020 11:25:36
1011 forum posts
9 photos

Here we go !

The 4 way is good for carbide as the height is always the same.

QCTP are good for HSS as you can vary the height for each tool as each one is invariably different, they also work for carbide.

Armstrong pattern tool holders save you having to grind any top rake as the HSS is held at an angle. These can be held by your existing triangle clamp and being old are quite cheap.

Personally I've found the QCTP not as clever as all that, if you don't buy enough holders for each tool bit. If you swap your double ended for the other end it needs adjusting as the ground height is never the same. I have an A&R Precision set (English made they used to supply Myford) after a big crash parting off the block is bruised and the moving parts are damaged on that side.

BTW this is a turret - you dont want one.

Edited By Dave Halford on 30/10/2020 11:43:09

mechman4830/10/2020 11:26:29
2788 forum posts
431 photos

I have a Dickson clone on my WM250V-F, a Bison + 18 holders all set with various tools, I have found these QCTP more than suitable for my needs. I still have the original 4 way block put to one side available for use as & when, but so far never needed. the majority of holders were purchased from RDG, usual disclaimer, at either Halifax MEW exhib' or Doncaster exhib; some have a M ( or inverted W ) stamped on but in all cases they all fit & I wouldn't change anything now.


erratum ..Halifax should read Harrogate.

Edited By mechman48 on 30/10/2020 11:49:21

ega30/10/2020 11:33:27
1850 forum posts
157 photos

I think "clog-heel" is the conventional name for the standard Myford toolpost; perhaps best used with their own Quick Set tools which use a radially rebated tool and "boat".

An easily made step up from this is the kind advocated by the late Len Mason amongst others consisting of a cylindrical column clamped to the topslide to which is clamped a height adjustable holder; the slot in the holder can be cut with a slot drill in the chuck and the holder clamped in position.

William Ayerst30/10/2020 15:38:50
58 forum posts

I was advised by RDG to go with 8mm tools for my 1956 ML7, which AFAIK took 3/8" originally - that means I'm going to have a 1.5mm +/- shim underneath every 8mm HSS tool if I use a normal four-way post, right?

Bazyle30/10/2020 16:00:42
5555 forum posts
207 photos

The topslide is not damaged by using a simple trianular holder as you always have a packer of soft steel or aluminium under the tool. After setting to height you keep the shims withthe tool as you change it so changes take no more time that a QCTP or a 4-way.

Redsetter30/10/2020 16:07:07
134 forum posts
Posted by William Ayerst on 30/10/2020 15:38:50:

I was advised by RDG to go with 8mm tools for my 1956 ML7, which AFAIK took 3/8" originally - that means I'm going to have a 1.5mm +/- shim underneath every 8mm HSS tool if I use a normal four-way post, right?

You always end up with shims under the tools because the working height of the tool depends on how it is ground.    You'll just have to get used to it.

Edited By Redsetter on 30/10/2020 16:07:45

Edited By Redsetter on 30/10/2020 16:09:22

Clive Brown 130/10/2020 16:10:38
536 forum posts
18 photos

At the risk of being tedious, I'll re-post my use of a Myford "clog-heel" that I had on my Boxford for years.

The tool-bit is 1/4" sq. The holder is 1" x 5/8" mild steel. The clamping screw is 2BA but M5 would be better nowadays. Cheap as chips, I made over a dozen and the tool heights can be pre-adjusted. Holders can also be made to take round HSS for boring tools.

I did use a 4-way toolpost for really heavy stuff, but not often.

The large clamp nut can be replaced with a handle for really quick tool changes.


William Ayerst30/10/2020 16:57:03
58 forum posts

Lovely stuff, thank you Clive - something for me to look into too I think, once I get to grips with the lathe. I just put a 1/2" tool into the clamp and was quite surprised to see it very far below the centre-line...

Given the choice I would prefer not to use a QCTP so glad to see there are reasonable options out there. I am happy to shiim but just thinking about what materials I would need to get it up to centre height.

I see there's a Myford ratcheting four-way toolpost on eBay that might be worth a punt but it's sans screws for the ratched onto the top slide. Some research suggests that there should be some screws that go through the ratchet gear into the toolpost which are missing - any ideas on what they might be?

ega30/10/2020 17:28:53
1850 forum posts
157 photos

It is tempting to be dismissive of the Myford device which is, however, quite well-designed. The apex of the clog-heel is, of course, supported by a screw adjuster with a ball and socket which sits on the topslide and the clog-heel is prevented from dropping when loose by a spring. The main clamp nut bears on a part spherical washer which allows for departures from the horizontal.

Before the introduction of the Quick Set tools Myfords marketed a toolset which from memory was similar to Clive Brown 1's above.

Rod Renshaw30/10/2020 18:00:25
196 forum posts
2 photos

The screws to hold the ratchet for the 4 way toolpost onto the Myford topslide are 2BA countersunk screws about 1/2" long.


John Baron30/10/2020 19:47:47
339 forum posts
142 photos

Hi William, Guys,

Why not have a go at making one !25-09-2018-006.jpg

This is a picture of my Norman patent tool post. No shims, rotates through 360 degrees, takes upto 1/2 tools. I also have one at the rear that holds the parting off blade and is interchangeable with the front post.


This is a picture of my rear one.

Clive Foster30/10/2020 20:54:24
2458 forum posts
81 photos

As regular forumites know I'm a considerable advocate of simple block toolposts held down by some sort of quick action nut as being the best price / performance ratio fit for the normally impecunious model engineer / home shop guy or gal. Especially neophytes having to talk fast when sliding expenditure past the domestic authorities!

Good QC systems are very effective but, as George says, a significant number of holders is needed to properly exploit the system and it all becomes rather expensive. For beginners in particular there are plenty of other things that the money might more usefully be spent on "right now". OK I have two larger lathes but, at E-Bay prices my two Dickson T2 posts sharing 16 holders are maybe approaching £1,000 worth. Yikes! Its easy to drop £500 or so assembling an adequately comprehensive set.

Conventional 4-way blocks are good, except for the porcupine effect and related tool length restrictions if the unused tools are not to argue with the job or parts of the machine. In practice some sort of ratchet angle setting device is desirable so tools always return to the same position when rotaing. Relatively complex to make and somewhat expensive to incorporate a good one in a commercial product. If using HSS the conventional four way also needs tools to be shimmed to centre height with the post on the lathe. Which can be tedious, especially should a mid job resharpen be needed when you really don't want to remove the workpiece.

Given a rapid release nut lift off tool blocks become practical. A simple pin or peg in hole or slot then becomes fine for rotational registration. Reground tools can be set to centre height on the bench. A simple jig with measurement capability lets you build up the correct shim stack before sitting it under the tool. Two slot blocks are probably the most sensible format. Reduced porcupine effect and less likely to have tools arguing with the a machine than a fully populated 4 way.

If you have no milling facilities screwing and gluing up stock plate and bar sections works just fine to make adequate toolblocks. For Myford size I'd probably make the centre lump out of alloy drilled and tapped through for countersunk 6mm socket head screws to hold the steel top and bottom plates on. Alloy taps much easier. If you have milling facilities Clive Browns system works even better in a solid block with a tool each side.

The simplest rapid release nut system uses a hollow castellated nut screwed into the top of the toolblock surrounding a rotating central "stud" cross drilled for a tommy bar arranged to engage in the nut castellations. Once adjusted a partial turn releases the tommy bar enough for it to be withdrawn allowing the toolblock to be lifted off and replaced by another whereupon an opposite partial turn locks things up again.

Probably easiest if just the top section of the stud rotates with a fixed bottom section of decent diameter having a slightly larger foot for rotation registration holes / slots. On a Myford I guess a foot something of the order of 1 1/4 - 1 3/4 inch diameter would work with a main stud maybe 1/4" smaller. Hollow top section with a socket head screw down it and top hat washer so it can rotate. If you use a pipe thread for the nut something out of the plumbing department would just need castellations cut.

I've always considered the Norman style post something of a missed opportunity. Doing away with the height adjustment and sitting the block direct on the slide makes for a much more rigid system. If you interpose a suitable notched or drilled plate rotational registration becomes easy. Re ground tools do need to be shimmet to centre height but, as mentioned above, thats straightforward on the bench.


Edited By Clive Foster on 30/10/2020 20:55:02

Edited By Clive Foster on 30/10/2020 20:55:34

Edited By Clive Foster on 30/10/2020 20:55:58

Edited By Clive Foster on 30/10/2020 20:57:15

John Baron31/10/2020 08:38:34
339 forum posts
142 photos

Hi Clive,

The height adjustment is built in ! The silver cap head screw bears on the top of the top slide and lifts the tool block as required. I have a height setting gauge to ensure that it spot on, though I find that the height of various tool bits doesn't vary very much. The biggest height variation is swapping for a commercial threading insert bar, then I have to raise it by two and a half turns from its usual position.

The Norman patent toolpost is just as quick to adjust as Dickson style and a darn sight cheaper ! From a hobbyist point of view I wouldn't go back to either the four way or the Dickson ones !

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