Harrison M300 – am I going crazy?

[Captain BigglesParticipant @captainbiggles]

[Captain BigglesParticipant @captainbiggles]

Please help!

I've just bought a second-hand Harrison M300 and am trying to get familiar with it (so expect more questions). The first thing I've noticed is that the handle for the longitudinal (transverse) feed has no dial on it – to tell how far the apron has traveled.

Unless I'm going crazy, this means that unless you're using the dial on the compound slide, you've no idea how far towards the chuck you've moved. I've studied photo after photo and video after video and not seen any concrete evidence of there being a dial on anyone else's machine, so was this standard?

I'll fit a DRO so it's not the end of the world, but can anyone put my mind at ease? What am I missing?

Thanks all,

Joel

[Clive FosterParticipant @clivefoster55965]

Yep. No carriage travel dial was nomal for ordinary lathes back in the day.

Tended to be found on the higher class and toolroom style machines. For all its considerable virtues the M300 was made as an economy lathe so a certain shortage of fripperies and refinements. Harrison figured the customer would rather the spent his, or her, money on getting the fundamentals right.

From an engineering point of view there are some issues involved in engineering a sensible rack pitch and gear ratio for a useful and accutate carriage travel dial.

My Smart & Brown 1024 has an excellent one. Given the eye-watering cost when new such refinements would have been expected. But my wartime P&W doesn't have one. Despite being a machine of sufficient performance that one might be expected. The manual has a note suggesting how the thread dial can be used as a travel indicator.

Clive

[DC31kParticipant @dc31k]

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

[Anonymous]

Can't say I've ever missed not having the carriage graduated on my M300. Generally if I need accurate lengths it's often a small spigot or hole only at one end, and I just use the top slide dial. On the rare occasions where I need an accurate length on a long bar I simply measure, put back in the lathe, touch off and use the top slide to remove the amount I need. For the rear axle on my traction engine I didn't even measuring, just machined by eye to a scribed line created on the job:

Personally I wouldn't bother with a DRO. On the Bridgeport a 2-axis DRO is the best bit of kit I ever bought, but on my lathe it wouldn't be useful.

Andrew

[Nigel McBurney 1Participant @nigelmcburney1]

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.

[Mike PooleParticipant @mikepoole82104]

If a shoulder or bore depth needs to be accurate then I set the top slide reasonably accurately and use the dial just for the final cuts to size. A rule or caliper is useful for getting close then a depth mic if more accuracy is demanded. If you are in the habit of using the top slide set at an angle to facilitate putting on a cut in thous or tenths then it can be irritating to have to reset. Using a dial gauge is also useful if you need to adjust the saddle with precision or a depth stop with a fine adjustment or even a micrometer stop. There is always more than one way to skin a cat.

Mike

[BazyleParticipant @bazyle]

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.

[Clive FosterParticipant @clivefoster55965]

Like Andrew I used to think that a dial on the carriage feed was an unnecessary luxury.

Until I got my Smart & Brown 1024 VSL which has one as standard. For about the first 6 months I carried on in the usual fashion with micrometer and turret type 6 rod bed stops set with gauge blocks or inside micrometers if beyond the micrometer stop travel.

Then I got a pesky job with about 7 steps in it so I pretty much had to use the dial. Job done and I was hooked. Worse than crack methinks. Now its a rare job that doesn't see it used. Once you get into the swing its just so easy. Especially when setting the stop rods in the multi-position stop. Pretty much everything gets a stop set as a matter of course.

Who needs a DRO?

I really miss that dial when on the P&W. Which may get a DRO just for that and to cover the lack of dual inch / metric dials.

Never liked the topslide parallel to the bed set-up so short steps can be machined to a lengh. Partly because my first couple of lathes were pretty much impossible set like that due to tailstock interference and partly because putting cutting forces mostly onto a feedscrew seems un-engineering. 25° angle off suits me much better.

Can't imagine struggling with a 2 axis DRO on a Bridgeport. Three axes on mine and a quill travel indicator opens up lots of sneaky tricks to make life easy.

Clive

[Captain BigglesParticipant @captainbiggles]

Thank you for the info all – most enlightening. I have to confess I've only ever used more recent lathes with a dial, with or without a DRO, so it never occurred to me there may have been another way.

Speaking of which, the link to the Harold Hall article on his website referenced by DC31k above is here: **LINK**

I've contacted a supplier of spare parts for the M300 as I thought I'd seen a drawing with the dial assembly in the manual and I was right, there was an option to specify this when purchasing the lathe from new. Most didn't bother however, which explains why I'd struggled to find any photographic evidence. I've asked for a quote, out of curiosity mostly as I still plan to fit a DRO.

You can also purchase stops directly from Colchester for the M300, for about £250 with or without micrometer adjustment here: **LINK** and a multi-position bed stop here: **LINK**

Cheers,

Joel

[Anonymous]

Posted by Clive Foster on 02/09/2020 13:14:00:Who needs a DRO?better.

…..opens up lots of sneaky tricks to make life easy.

Such as?

Andrew

[Clive FosterParticipant @clivefoster55965]

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

[Clive FosterParticipant @clivefoster55965]

Andrew

Sneaky tricks are mostly multiple variations of using quill and knee travel to set depths of cut et al and help moving around features on the job. I'm sure you can do such things with the dials but DRO's make life so easy. Especially when you get into exploiting the multiple offset memories.

For example my standard way of setting depth of cut is to crank the knee up close, drop the quill down a little so the cutter touches the work, lock it and zero the DRO Z axis to define my reference plane. Drop the knee so the cutter clears the job and move over to the start of the cut. Bring the knee back to zero, add cut and go. Far faster to do than to say.

With drilled holes that have to go to a specific depth I'll pull the quill down to around 1 cm – 1/2" (ish) further than the hole depth, set the quill stop, lock the quill and crank the knee up to touch the end of the drill. Zero the Z axis, unlock the quill, take it back to the top and crank the knee up by the depth of the hole. Lock knee and drill hole, move to next and repeat.

As I've never used a proper size mill without a 3 axis DRO there are a fair number of things I do without thinking about it because the DRO makes life easy.

I have a time served trained toolmaker friend who occasionally borrows my workshop. Theory was he'd teach me things. Practice is more me teaching him on the Bridgeport because they didn't have DROs back then. I'll do something automatically and he will be like "What are you doing! Ah, I see. Cheat!".

Clive

[Howard LewisParticipant @howardlewis46836]

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 RenshawParticipant @rodrenshaw28584]

Always something new to learn on this forum.

I was thinking of a 2 axis DRO for my mill but now I have seen Clive's posts I will get a 3 axis one, and perhaps a scale for the quill as well!

Rod

[Clive FosterParticipant @clivefoster55965]

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

[not done it yetParticipant @notdoneityet]

I believe one can now get combination scales so that the mill knee and quill can sum their changes/movement.

Might be useful (for some) on their long travel and top slide for their lathe? (I try to never use them in combination)

[KettrinboyParticipant @kettrinboy]

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

[Anonymous]

Clive: Thanks for the exposition. When I was looking for a DRO I considered a 3rd axis. But I ended up buying a professional DRO (Newall) and the 3rd axis was a significant increase in cost. That's important when spending ones redundancy payment!

I must do simple machining as I don't miss a 3rd axis readout or a quill scale. I've never needed to drill a blind hole to an accuracy better than that obtainable by visually setting the quill stop. Likewise it's fairly rare that I need to pocket out or mill down to a specific depth with any degree of accuracy. When milling the quill is fully up, locked and never moved. These valve chests were milled to a specific depth (although not strictly necessary as the valve floats vertically):

The valve chest cover face was already machined and set parallel to the table in X and Y. I then touched the tool on the cover surface, as indicated by a fag paper. Set the Z dial to zero and job done. The cylinder is being machined imperial but my Bridgeport is metric. On the drawing it is simple to dual dimension and a few seconds with a calculator gives the number of complete turns and remainder. I machined down in steps, keeping count of turns. Before the last full pass I extracted the cutter and did a sanity check on the number of full turns, as well as blowing the swarf away with a bendy straw. Easy then to do the final full pass and partial pass, leaving about 4 thou for a slow finishing pass. Endmills with radiused corners give a really nice finish. I can't get into measure it but probably better than a micron Ra.

Andrew

Dunno quite how we got here from an M300. My only excuse is that my Bridgeport and M300 are next to each other.

[Clive FosterParticipant @clivefoster55965]

Posted by Andrew Johnston on 03/09/2020 11:17:07:

Clive: Thanks for the exposition. When I was looking for a DRO I considered a 3rd axis. But I ended up buying a professional DRO (Newall) and the 3rd axis was a significant increase in cost. That's important when spending ones redundancy payment!

I must do simple machining as I don't miss a 3rd axis readout or a quill scale. I've never needed to drill a blind hole to an accuracy better than that obtainable by visually setting the quill stop. Likewise it's fairly rare that I need to pocket out or mill down to a specific depth with any degree of accuracy. When milling the quill is fully up, locked and never moved.

Andrew

Dunno quite how we got here from an M300. My only excuse is that my Bridgeport and M300 are next to each other.

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

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