It is quite rare for the carriage handwheel to be graduated.

Some high end machines and clever manufacturers do it but it is not the norm.

The reason is that the the apron moves due to the action of a pinion on a rack fixed to the bed. For the wheel to have sensible graduations, the rack would have to be of circular pitch specification (i.e. its teeth some easy rational number of chosen unit apart).

For length measurement without DRO, a (micrometer) bed stop and spacing pieces can help. I believe Harold Hall published something on this, so check his website or early back issues.

Another option, liked by the Myford brigade, is a graduated wheel on the end of the leadscrew and use that with the half nuts engaged.

Edited By DC31k on 02/09/2020 11:30:22

I have owned a number of Colchester lathes,and I believe Harrison lathes are part of the owning group, my current Colchester ,a 1970s Master 600 is an imperial lathe fitted with dual dials (imperial/metric), now I did a naughty,when I bought the master I still had a metric Colchester student now this was fitted with a saddle handwheel which had a metric dial which indicated the travel of the saddlein metric units so I tried it on the saddle of the Master and it indicated accurate metric travel even though it was basically an imperial machine with imperial lead screw, so I kept it on the master and eventually passed on the student minus its dial.So for an imperial machine the rack and gearing in the saddle must be metric.Very useful ,now having served my apprenticeship 60 yrs ago by habit I work mainly in imperial as thats the way I was trained so now I use the top and cross slide in either metric or imperial and use the metric only saddle dial ,its ok I have just get used to it,I dont know if Colchester offered a dual dial for the saddle dial ,if they did it no doubt cost a fortune,Colchester spares costs are eye watering. Also at the time I also had a colchester Triumph ,this was a full all metric machine including a metric leadscrew,the saddle had wheel had a machined feature to recieve a dial ,and after some checking I found that the rack was metric and a dial could be fitted to the saddle handwheel which would indicate 25 mm for one turn exactly. So I found a merical dial at a local tool dealer,it was not Colchester but it was soon made to fit. Now Colchester and Harrison having a common link it may be worth checking if the Harrison also has a metric rack,it would then be easy to fit a dial .Getting back to the original query,in the olden days the majority of lathes did not have any means of indicating saddle travel,even a new expensive 1967 toolroom lathe I worked on had no way of measuring saddle travel, but of course no one worried you were trained to turn using topslide ,or bed /saddle stops stops or a good 2 foot rule,So dont moan about it just get on with it at least you have a decent built English lathe, the victorians had it a bit harder a lot or evem most of their lathes had no dials, when I was young ,my very old neighbour still owned his fathers machine shop,the lathes,belt driven ,2 six inch and one 12 inch centre height had no dials at all,it was a case of marking the handles with chalk and universal use of rule and firm joint calipers ( never spring joint) , and just look at what the Victorians produced.though the universal trade term "fitter and turnet" was literally just that,you turned the work and then fitted it ,the scraper was a popular tool.

When do you actually need to know the saddle travel? Perhaps for shoulders on each end of an axle so make yourself a multiple way carriage stop. More accuratea and repeatable than a handwheel dial. For ultimate accuracy some toolroom lathes had a little tray set up to take slip gauges as stops so accurate to better than a thou in theory.

Don't waste your money on either Colchester stop. Both poorly designed and stupidly over priced.

The micrometer one has a badly placed and hard to read dial, better breeds have a much bigger dial on a smaller body so the dial graduations are on the same or similar plane as the body with a nice, legible, reference mark.

Relatively coarse threaded screw in stop rod extensions on the multi-position type are a total PIA to use. Sliding rods with a transverse clamp screw are so much easier to set. Especially with carriage dial or DRO. Piece of cake to make extra rods too.

But Colchester have form when it comes to odd bed stops. My pal Mike has a Student MK2 with a 2 ft long tube sat out the right hand end of the carraige drilled and tapped for 6 rows of stops carrying short setting bolts.

Interesting to read the comments from Mike and Bazyle about how they do things without a carriage dial. Now I've got used to a dial my immediate reaction is "Gawd, what a faff." which should honestly be followed by "Thats pretty much what I used to do and thought nowt of it.".

Clive

None of the centre lathes in the Apprentice training school (DSG, Edgewick ) in the late 1950s had graduated Saddle hand wheels, as far as I can remember. Cannot remember using anything other than a depth mic.

My 12" swing dual dialled Chinese lathe (BL12-24 = Warco BH600 / Chester Craftsman; made in 2003) has a dial on the Saddle Handwheel.

It is reasonably accurate, rather to my surprise. The vital components are a 13T 1.5 Mod, gear engaging the rack, driven by what look like 1.5 Mod reduction gears in the Saddle.

If I want greater accuracy, I use a shop made Micrometer stop, using a M&W micrometer barrel which, judged by the configuration and graduations, seemed to have been intended for such a task..

For its ML7 predecessor, I made up a Handwheel for the Leadscrew, with 125 graduations. ( A Picador wheel using the optical dividing head in the Standards Room,and a vernier height gauge, in the Standards Room on a Saturday morning!)

For the mini lathe, I made up a graduated Handwheel for the Leadscew, based very heavily on the design (In concept if not exact dimensions ) shown by Alastair Sinclair, (just reprinted in MEW 296 )

Howard

Rod

If your mill is a Bridgeport or similar knee mill with decent quill stops I think a quill scale is something of a luxury. I put a BW electronics pull wire scale on the Bridgeport quill back in 2006 or thereabouts as it fitted much more neatly than the usuall Quillstar clone style. Used it a lot initially but, over the years, my machining style has shifted to make much more use of stops and I rarely use the quill scale now.

Clive

Some years ago i made a traverse dial for my Harrison L5 , i used the drive gear from the unused thread indicator , then I made a housing to bolt into the same hole as the thread indicator , it can pivot to give the desired mesh with the leadscrew , I see no need for a DRO now as this is pretty accurate and easy to get within 0.05mm and if greater accuracy is needed then i,ll get the depth mic out.

regards Geoff

Edited By Kettrinboy on 03/09/2020 08:50:17

Yep, care when spending redundancy payment is important.

3 Sino axes seemed better value to me than 2 Newall ones. Worked well for me. YMMD.

We all develop a way of working that suits our jobs, equipment and experience. I see enough repair, unobtanium fix or "no one else is mad enough to take that on" jobs that its handy to be able to use the Bridgeport as a sort of manual co-ordinate measuring machine during set-up. Main thing I use the quill scale for these days. I can do without having to make proper drawings of a component where the reference surface has been machined off before I can figure out what cuts it will stand to add repair parts. Thing in co-ordianates was pretty much essential for my job with MoD so I was primed to work a mill that way.

Thread drift will always be with us.

Clive