Boring bar height setting

[Gordon]

After all the years that I have been doing this I should have figured out the proper way. Does anyone have a good method of setting the height of a boring bar? When setting tool height on OD the ruler method works well but that does not work on ID. I have made gages to set tool height relative to the compound but usually the boring bar is several inches away from the compound. I have tried making gages working from the bed but my South Bend has a flat on one side and a V on the other side so short of making a special piece to fit the bed I have not found a good way. Depending on the shape of the piece being bored I sometimes can use my caliper to measure from a known surface to the top of the cutter but that does not always work. There has to be a better way than just keep trying until it seems to be working.

 

[Jasonb]

Ruler can still be used, put it against the far rear side of anything round held in the chuck and wind the boring bar past the work and then bring it back towards you to pinch the rule.

 

[Gordon]

Ruler can still be used, put it against the far rear side of anything round held in the chuck and wind the boring bar past the work and then bring it back towards you to pinch the rule.

I have done that but when the piece is not round it does not work. I guess that I will have to take the time to make a saddle to fit my lathe bed so that I have a flat surface to measure from.

 

[Lloyd-ss]

I have a QCTP so I can sometimes set the boring bar height once and forget about it. For the initial setting a piece of round stock with a tiny nub sticking out the end as a setting point usually seems good enough.

I bore a lot of tiny holes with hand-ground HSS boring bars and often I have to set the tool above the centerline just to get it to fit into the hole without rubbing. Honestly, with the light cuts I usually take, so long as I don't have the cutting edge set below the centerline, the boring usually goes fine. And with the HSS, the top rake angle can be tweaked to get a neutral cut.

But Gordon, I guess you are talking more about bars with replaceable carbide inserts? They certainly are less forgiving about set-up.
Lloyd

 

[Jasonb]

Gordon as I said put a "Bit of bar" in the chuck you can do that before mounting the work to get your boring bar on height.

Or simply swing the toolpost around and use the side of something held in the tailstock chuck or side of the the tailstock steady if you have work in the main chuck you do not want to disturb

This is why I like my QCTP as I have about 5 or six holders all with different parts mounted in them so simply swap them in and out as needed and height only gets set the very first time one is used.

 

[timo_gross]

As I undertand the video, I stumbled in, shows a luxury version of the ruler method?



Swing around to the tailstock and use Tailstock (as suggested by Jasonb) should also work with that waterlevel luxury device. I sometimes just put a small center drill in the drill chuck, then look with magnifier if they are same height.
I have bought one set of insert boring bars. Fortunately one proper spacer block can adjust all of them without re-measuring. (unless I misplaced the block yet again).

 

[Steamchick]

Gordon,
Jason is right:
But as I use a 4-tool tool post but use more than 4 tools, I have to pack the tools with steel shim beneath to get tools at the correct height (on - not above - centre). So many of my tools, siting on the shelf, have the packing shims glued beneath them using a "loctite" anaerobic adhesive (Screw-lock is OK) from the day they were set-up. So I can quickly change tools in the 4-post tool holder and know they are pre-set to the correct height. And yes, I use the "ruler method as well as "rack-of-eye" onto a turned centre-point on the end of a piece of bar held in the chuck.
It is satisfying at the start of a job to plan the tool rack - and a few alternative tools - and do the tool-makers' set-up of all the tools that then makes the machining job just that. Not "Machine a cut - set-a-tool - Machine another cut - set-a-tool, etc." interrupted flow.
Of course, if you want a "centre check when cutting" a boring bar can be rotated to act as a facing tool and facing a piece of scrap will always tell to if you are high or low. - All you need a 0.002" cut on a piece of brass, so it hardly costs any metal. I have checked the bar this way using "the job" before drilling (from the tailstock) and using the bar.
The only time I remember using a "height gauge" (scribing block and scriber really) from the bed against the tailstock centre and tool point was on a 15 foot long bed, when I had castings for cross-heads (10" OD x 18" long") in the chuck, so once in they stayed there for the duration of all the cuts. Setting the boring bar, for machining the cross-head tapered bore and rod connecting thread was done to a scriber point set from the tailstock centre. (Or a line scribed on the adjacent paintwork on the tailstock for when the centre was in use and a side cutter needed setting). We could not use the "rule" method simply because the job was large enough that the cross-slide could not travel far enough past the job so the boring bar could be presented to the far side outside face.
You can even make a simple scriber height gauge from a piece of rectangular bar with a true flat on one side - to sit across the bed - with a hole and locking screw to hold a scriber (or other suitable wire, with a short "L" to a point) that you can set from your "perfect" tool setting of (say) a side-cutting or facing tool, to transfer that height to the cutting point on the boring bar...
Sorry to be long winded but maybe it gives you and idea that there are many ways to set tools...? - Whatever suits best at the time?
K2

 

[BaronJ]

Hi Guys,

I made a lathe tool height gauge which gets me there every time inside or outside !

On top of the post allows me to set the rear parting blade and under the cap allows me to set the tool height. I stuck a paper label to the bottom in order to stop it slipping on the cross slide surface.

 

[Steamchick]

Timo has money to spend on toys. The pyramids were built using "the ruler and square" and those tools are still "true".
K2

 

[timo_gross]

Timo has money to spend on toys. The pyramids were built using "the ruler and square" and those tools are still "true".
K2

Guilty, i am definitely at risk to become the salesmans dream . But I try not to buy everything I see, but I buy more than I need.
Hobby: "When you put a renishaw tool setter on your infamous mini lathe!"

For the lathe tool height, I am quite on the same page as you describe. Never got around to spend money on quick change tool post.
Things I take away and maybe can train myself to do.
a) I always think I should put the packing in a small box together with the tool. (never did this)
So gluing the packing under the tools will be a practical alternative. (will definitely try that)
b) Start planing ahead a little better and set up the tools before starting

 

[Steamchick]

I just enjoy setting tools sometimes... I then enjoy the machining without interruption... often on the next session, not straight away.
Good preparation and planning, then machining, is more rewarding when the machining is trouble free and uninterrupted.
K2

 

[BaronJ]

Hi Guys,

I made and use a "Norman patent" style tool post ! Easy to make and adjust for height and angle. I also made a rear tool post one, with the front and rear tool holders interchangeable, so I can swap them around at will.

The attached drawing is sized for the Myford S7 lathe.

 

[Steamchick]

My "failing": I don't keep a record of machining sequences, set-ups, etc. I use chalk on a blackboard.... then rub-off afterwards.
I should write it all in a note book, for later reference (WHEN...??).
K2

 

[Steamchick]

I use a "Norman" tool post in the back position for the parting tool. Because it is clamped to a pillar, if the clamp isn't too tight, when the parting tool snatches (if I fail to keep a smooth feed) then the tool lol er simply slides up a nudge and does not break tools, or damage the workpiece. Easy to reset to the screw stop with a mallet and soft drift...
For my unreliable hand-feed it is the best parting "safety" that I have!
The only reason I rarely use it in place of the 4-tool post on the front is because the 4 tools are the ones I have set for the job - with a very quick change so I can concentrate on the machining process.
K2.

 

[Peter Twissell]

My "failing": I don't keep a record of machining sequences, set-ups, etc. I use chalk on a blackboard.... then rub-off afterwards.
I should write it all in a note book, for later reference (WHEN...??).
K2

My phone contains many photos of blackboards, whiteboards, other people's notes etc.

 

[Steamchick]

I talk to people using my phone.
K

 

[ajoeiam]

Guilty, i am definitely at risk to become the salesmans dream . But I try not to buy everything I see, but I buy more than I need.
Hobby: "When you put a renishaw tool setter on your infamous mini lathe!"

snip

That really got me a laughing!!!!!
(Excellent description!!!!)

 

[trlvn]

I talk to people using my phone.
K

Jeez, they keep coming up with new stuff all the time!



Craig

 

[Lloyd-ss]

Jeez, they keep coming up with new stuff all the time!



Craig

Wow, the planets must be in some sort of weird alignment right now, and I bet the OP, Gordon, is rolling his eyes.
Serious detailed replies by people trying to keep a straight face, interspersed with some hilarious thoughts by the class clowns! Ha Ha, I love this.

But now, speaking with a straight face, I do keep note books for all "serious" projects that are chock-full of good information that I have probably forgotten and might never look at again. And there are all of the junk mail envelopes with even more important stuff written on the back that end up going to the recycling bin.
Gordon, My apologies for staying in the ditch. I tried to steer out of it, honest., LOL.

 

[Lloyd-ss]

I just enjoy setting tools sometimes...............
K2

(just a quote of the the most damning part)

That sounds like a confession at a 12-step self-help meeting.