Tool Centre Height

[Steve WithnellParticipant @stevewithnell34426]

How good is this? A gimmick or useful? – lathe tool height setting

[Steve WithnellParticipant @stevewithnell34426]

If this is any good, it would have been very useful for my last job, but I’ve been done before

 

 

http://www.ebay.co.uk/itm/Center-height-gage-metal-lathe-toolbit-tailstock-setu-/360161721676?pt=LH_DefaultDomain_0&hash=item53db4fbd4c#ht_881wt_905

 

Steve

 

[AndyBParticipant @andyb47186]

Hi Steve,

 

For the money a 6″ rule and a square do just as well

 

Andy

[Tony Pratt 1Participant @tonypratt1]

Damm, I’ve been waiting 40 years for just such a gadget, seriously though I wouldn’t waste your money.

Tony

[Chris TriceParticipant @christrice43267]

You can easily see if your headstock and tailstock centres are out without a gauge (and that assumes the centre tips aren’t damaged) and I question how accurately you can set your tool height in the manner shown. I use a much simpler type consisting of a base that sits on the bed or the saddle with an upright post and a flat bottomed arm that’s adjustable for height up and down the post. When the top of the tool just touches the underside of the arm, you’re there. Simples. If you want to get creative you can shape the arm so you can set up a normal tool and an inverted parting off tool in a rear tool post.

[David Clark 13Participant @davidclark13]

Hi There

The old saying ‘They can’t all be wrong’ appears to be incorrect.

I think personaly, they are all wrong, all 83 of them that bought it.

I would not buy one.

I doubt I would use it if someone gave it to me but I would not use the 6inch rule method either.

 

regards David

 

[Chris TriceParticipant @christrice43267]

I’m a great believer in KISS. Keep It Simple Stupid. The more complicated you make something, the more opportunity for Mr Cock Up to visit.

[chris stephensParticipant @chrisstephens63393]

Hi Guys,

Take a look at Machine DRO, they do a tool height gauge or two.

http://www.machine-dro.co.uk/edge-technology-new.html

chriStephens

Edit

PS no connection with the firm, except you could say I put them onto the items. 

Edited By chris stephens on 04/08/2011 23:25:08

[Richard Willcox 1Participant @richardwillcox1]

And in 20 years time no one will be able to work without one !

[Martin WParticipant @martinw]

Hi

 

I might be wrong but I believe that if your lathe isn’t dead level both X & Y axis then this kit is worse than useless as it will give a false reading when indicating true. Far better to turn off to a fine pip and make make a gauge using this tool height to the lathe bed.

 

If its a ‘really must have item’ then first get an engineers level and set your machine up to be spot on. It may work then but I wouldn’t bet on it.

 

The other problem is that in the description it says that it is I quote; ‘ made not of plastic but of sturdy, anodized aluminum with an acrylic bubble vial’. How long is aluminium going last, even if it is anodised, being trapped between two hardened steel centres or between an HSS, or harder, tool tip and a metal bar !! Not long I think before the aluminium gets marked up with high spots etc. Not only that but you can’t use it to correct any lateral offset errors between the headstock and tailstock.

 

 

Cheers from an old sceptic.

 

Martin

Edited By Martin W on 05/08/2011 00:15:33

[chris stephensParticipant @chrisstephens63393]

As for the lathe not being level, some of you might have seen the one I had on the SMEE stand at Ally Pally, which used a digital level. The advantage being that you could set “zero” on, say, the top slide and then “level” the tool height. These devices clearly work best on quick change tool posts, where the height is easily adjusted by screw, rather than standard ones where shims are needed. I made my digital one to see if the idea worked and it maybe a toy, but where would we be without our little playthings?

 

As for “anodized”, well it depends on the style of anodizing, doesn’t it. There is anodizing which is mostly decorative, pretty colours, and then there is the hard variety which is almost impossible to even scratch. I do suspect that the items in question are merely the pretty type, though.

 

An arch sceptic and cynic,

chriStephens

 

 

[Jim NolanParticipant @jimnolan76764]

Having sold one lathe with a QCTP I am now back to a standard 4 way. So I now do far more tool setting than I ever did. I would recommend either of the edge technology setters now sold by Machine DRO. I have had one of the round bar types for a couple of years and its great. More recently I have purchased their latest version for when I already have bar stock in the chuck.

Quick accurate and easy to use and for people like me who’s lamp oil seems to dim the nearer you get to things looking at a nice big yellow bubble beats a ruler any day.

Jim

Oh I realise I have used some abbreviations in this post so just in case that kicks off another debate. If you don’t know do what I do stick it in Google the internet has an answer for just about anything.

 

[Clive FosterParticipant @clivefoster55965]

I like the optical type as described in MEW some years back. Basically a thick lump of perspex fixed to a suitable base so it stands straight up having a line scribed at centre height on both sides with a mirror at 45° (ish) fixed to the back so you can look down and see the lines. When both lines and the tool tip are superimposed tool is on centre height.

 

Ideal for my Smart & Brown 1024 with its large areas of flat surfaces. Great thing is that you can scribe the lines in situ with a sharp centre. Obviously best for QCTP or Armstrong type holder systems where the tool height is easily adjusted by screw or sliding. Worth remembering that a fixed Armstrong holder makes a fairly good QC system if you simply swop tool bits and centre to centre height. Need system for interchange of bent right, bent left and boring tool holders but there are ways of doing it easy and inexpensive.

 

If shimming is your thing consider making an off lathe jig with an indicator to measure tip height from the tool base so you can sort shims immediately after sharpening. Alternatively mark the tool with paint dabs, alcohol based marker or whatever. Good source of shims is old hacksaw and band-saw blades with the teeth ground off. The plastic colour coded stuff is quite acceptable too being easy to organise but it does require an intermediate plate between it and the tool. Often thought that a good way would be to arrange your too grinding jig so the top grind is in suitable shim thickness steps so you know what you have.

 

Clive

[John HinkleyParticipant @johnhinkley26699]

Alternatively, see page 32 of MEW issue 180. It works for me – but then I’m biassed!

 

John

[jomacParticipant @jomac]

Hi, whats wrong with putting a pointed rod in either the chuck or the tail post chuck, and then adjust the hight, I glue my shims to the base of the tools, with contact adhesive, then screw down the lock bolts to squeeze out any glue, that way they dont get lost, As I have many tools, I dont need to sharpen them very often, so new shims are not required on a regular basis, especially if using insert type tooling. Works for me!!!!.

John Holloway.

[John Stevenson 1Participant @johnstevenson1]

Why even bother bringing it up ?

 

Mark 1 eyeball to get as close as possible, light facing cut and watch the pip, adjust to suit.

 

Far quicker than even looking for some gismo and at the end of the day the pip tells you what is, not some bit of fancy tat that may not give the required result anyway regardless of what it says.

 

I can set a tool up in 10 seconds max doing it this way and I know it’s correct because the machine tells me.

 

John S.

[NJHParticipant @njh]

Made this 35 years and 4 lathes ago – still works every time!

Cost – nothing.

 

Regards

 

Norman

 

Edited By NJH on 06/08/2011 10:35:46

[Ian S CParticipant @iansc]

No photo, but mine may be even simpler, and cheaper, I just put a center in the mandrel, used it as a scriber, Took the 6″ square and marked a line across the blade. Ian S C

[Chris TriceParticipant @christrice43267]

I use the same as NJH too. It serves the same purpose as the pip (which also works) but you can set the tool correctly straight off without having to take a cut each time. If you change tools halfway through a job (which has been known), how can you use the pip without unchucking the workpiece and chucking a fresh piece of metal which you have to do if the work is centre drilled each end?

Edited By Chris Trice on 06/08/2011 11:17:47

[BogstandardParticipant @bogstandard]

This is how I got around my tool centre height setting. Maybe a bit long winded, but it does go into reasons for NOT using certain methods.

 

 

Finding centre

 

 

John

[John Stevenson 1Participant @johnstevenson1]

Use the centre rings left from the last cut or if centre drilled and it’s not a number 37 centre drill with a pilot of 1 1/4″ then eyeball it.

 

Contrary to what many think the tool doesn’t have to be on centre to nanognatsbollocks , in fact I have always been of the opinion that on small lathes setting to centre high using a gauge will actually leave a pip as real world forces push the tool lower due to lack of rigidity.

[Chris TriceParticipant @christrice43267]

All true but then there are many ways to set the tool adequately approximately right by eyeball including scribed lines on squares, centres, etc. It’s also true that on ‘small’ lathes the work is often of a ‘small’ diameter where tool height needs to be more accurately set. My personal preference (because I’m naturally lazy) is to use the height setter as above because it’s quicker and easier without having to traverse the saddle to a new location or take a test turn. I get consistently good, reliable and accurate setting of the tool everytime, certainly to within the limits needed for anything other than watchmaking. Trapping a flat object between the tool tip and the bar is an old ploy more commonly used for centring a drill over round bar when through drilling but I’d put money on the height setter getting it right more times than a ruler pressed against the work.

[john jennings 1Participant @johnjennings1]

I use a simple system advocated by John Wilding the Clockmaker.

 

Take suitable length of free cutting hexagon bar (1/2″ AF plus ) face off one end.

 

Mark off the required length equal to the centre height above the lathe bed and face to this length. Then stand the bar upright on the cross slide upper surface and remark centre height. Turn the length above this cylindrical and a little smaller diameter than the AF dimension.

 

Use either full or reduced height to set the turning tool depending on which location is most convenient.

 

Repeat for your second lathe.

 

Simples

 

John

[Chris TriceParticipant @christrice43267]

Same principle, just the other way up. As you say, simples.

[JonParticipant @jon]

At last someone else that sees it my way John S, mark 1 eye ball works every time no faffing about exactly spot on every time.

 

Any other method relies on eye sight, operator and angle looked at, any one of the three out will the gizmo useless.

[Author]

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