Dead simple lathe tool height gauge

[mklotz]

Like most neophyte machinists I soon realized that I needed a tool height gauge for setting the height of my lathe tools. My research uncovered a succession of what I can only describe as the most over-designed, complicated, hard-to-use devices I could imagine. As a devotee of the idea that simple is better I made a gauge that consists of nothing more than a block of steel relieved on the bottom...

so that it will sit flat and not rock when placed on a flat surface. The height of the block was carefully machined to match the height of the lathe spindle above the top of the compound. (Thankfully, my compound has a flat top; not all lathes do.)

Its use is simple. Push it up against the tool tip and slide your thumbnail back and forth between the gauge surface and the tool. Millions of years of evolution have made our fingers extremely sensitive; you'll be able to detect a few thousandths height difference and tell whether the tool is high or low as well.

[Toolmaker51]

Total agreement on the utilization of fingertip as an indicator. The more users do it the better they'll get. Never understood why 'center height' was made so mysterious. Spirit levels, LED lights, or devices contacting the tool's top edge...waste of money unless there isn't a convenient reference surface like some CNC's.
Bottom edge benefits from that relieved area. Can press in 3 bearing balls instead, hard very long lasting contact and ultimate avoidance of debris.
I make one for each lathe. Mine have 2 steps; one as it rests on carriage if flat, or a bed resting on ways. The step checks height on the compound - for setting turret tool posts. Saves dropping shims into the chip pan. Tip: In QCTP, set small boring bars in left dovetail first.

May I add how to determine center height? Turn a diameter, measure it, and record the dimension divided by 2 [half]. Then from top of carriage, or aforementioned cross bed over the ways, or top of bare compound; touch off height gauge on top of turned section. Subtract the half diameter calculated prior. Result is center height. Make a card, use a felt tip, but attach it to headstock. That also is target dimension in machining Marv's tower for yourself.

[DIYer]

Thanks mklotz! We've added your Lathe Height Gauge to our Lathe Accessories category,
as well as to your builder page: mklotz's Homemade Tools. Your receipt:

Lathe Height Gauge by mklotz

tags: lathe, height gauge

[Moby Duck]

And once your tool is set up perfectly on centre height, if it doesn't cut properly, lower it a few thou below centre using your Mk1 Eyeball estimating device, until it cuts to your satisfaction.
Seriously though, this is a great little tool that you have made here, and a great thumb nail tip too.
After seeing Toolmaker51's comment and his logical way of determining the exact centre height I would be interested to know how you Marv determined the exact height to make the block. In my opinion your problem solving is brilliant and I am sure that you would have done it in a unique way. Just interested that's all.

[mklotz]

I'm afraid my method wasn't very exciting or innovative. I already had, through much fiddling, shimmed a facing tool to be perfectly on center and leave no trace of a center pip when cutting a variety of materials, even softish aluminum. I merely stuck the height gauge on the top of the compound and measured the height of this tool, then duplicated that height on the gauge I made.

Had I not had that already-centered lathe tool available, I would probably have used a method very similar to what TM51 described.

I've seen people advise using a dead center in the tailstock as a height center. For me there are two problems here. First, many lathes do not have the tailstock perfectly aligned in the vertical with the lathe spindle axis. (Errors in this plane are not nearly as apparent as misalignments in the horizontal plane.) Secondly, at least for me, aligning anything to a sharp point is not as easy as aligning to a plane.

If you use TM51's method, be sure you have a truly cylindrical rod and hold it in a collet or, lacking collets, use a 4jaw and take the time to get it running true.

[tonyfoale]

I'm afraid my method wasn't very exciting or innovative.

Maybe not, but it is simple, accurate and easy to use. You can't better that.

[Toolmaker51]

I'm afraid my method wasn't very exciting or innovative. I already had, through much fiddling, shimmed a facing tool to be perfectly on center and leave no trace of a center pip when cutting a variety of materials, even softish aluminum. I merely stuck the height gauge on the top of the compound and measured the height of this tool, then duplicated that height on the gauge I made.
Had I not had that already-centered lathe tool available, I would probably have used a method very similar to what TM51 described...If you use TM51's method, be sure you have a truly cylindrical rod and hold it in a collet or, lacking collets, use a 4jaw and take the time to get it running true.

Marv's establishment of tool height by physical test is accurate and effective; pointing out that he shimmed until the pip was eliminated. His, as some lathes haven't a machined top crosslide; so the compound is a natural.
The alternate is turn a diameter and measure; collets or 4 jaw wouldn't be a requirement, just a skim cut with decent finish Size is beneficial, but not crucial at all.
For cast surfaces there is a solution too. Construct a base having three contact points with corresponding areas on the crosslide, close enough to reach toolpost.
For example; might be 3 locked setscrews protruding from the slide into center drilled pockets of the base.

[mklotz]

And once your tool is set up perfectly on centre height, if it doesn't cut properly, lower it a few thou below centre using your Mk1 Eyeball estimating device, until it cuts to your satisfaction.
Seriously though, this is a great little tool that you have made here, and a great thumb nail tip too.
After seeing Toolmaker51's comment and his logical way of determining the exact centre height I would be interested to know how you Marv determined the exact height to make the block. In my opinion your problem solving is brilliant and I am sure that you would have done it in a unique way. Just interested that's all.

If you're interested in different/unique ways of doing shop things, you might enjoy both of these topics...

http://www.homemadetools.net/forum/s...ug-gages-27355

http://www.homemadetools.net/forum/o...maneuver-27357

[Jon]

Congratulations mklotz - your Lathe Tool Height Gauge is the Homemade Tool of the Week!

The "simple" theme is a favorite around here, and it was certainly prevalent this week. There was also another Dead Simple Lathe Tool Height Gauge by tonyfoale, and a Simplest of All Tool Setter by olderdan. The meta-theme of that theme, getting inspiration (or even reminders of previous builds) from seeing others' builds, was also out in force. In addition to this trio of tools, there was a popular Engineer's Hammer by aphilipmarcou, who was inspired to post that build after seeing rossbotics's award-winning Brass Shop Hammer.

This habit of using ideas as fodder for reminders of previous builds and iteration of future builds is a clear sign of a healthy intellectual community (online, offline, anywhere really), and it couldn't be more obvious this week. A cognitive anthropologist examining this community could point to this as an example of the differentiation between Communities of Interest (most forums), Communities of Practice (the good forums), and Communities of Innovation (the best forums).

Other nice builds from this week: an Engraving Pantograph by brianhw, a Camera Stabilizer by Brendon, a Sheetmetal Brake by Tuomas, a Nail Punch by Philip Davies, a V Block Setting Aid by mklotz, a Hand Wrench by sossol, as well as a few nice builds from PWelder, including a 2x72 Belt Grinder, a CNC Plasma, and a Hydraulic Pipe Bender.


mklotz - you'll be receiving a $25 online gift card, in your choice of Amazon, PayPal, Giftrocket, or bitcoin. Please PM me your current email address and gift card choice and I'll get it sent over right away.

This is your 9th Homemade Tool of the Week win. Here are all of your previous wins.

Congrats again and nice job

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[Christophe Mineau]

Yes, completely agree , Simple Is Beautiful !
Congrats Marv, well deserved !
Christophe