[MFchief]

Now for something completely different. LoL

I have always used the granite block with a hole in it, with a height gauge to set my tool offset lengths, but I've never been too happy with it. I always seemed to get slightly different measurements every time I checked a tool, not a lot, but enough that, like I said I wasn't happy.

Then it occurred to me that I have a digital probe, so I place the small Tormach granite block on the mill table, zeroed the probe there and then used it to set the lengths of all my tools. I found most of them were slightly off, usually a thou or two, but some were significant errors.

Of course the problem with this method it that most probe tips are spherical, making it hard to get an accurate trigger. I happened to have a Renishaw break away section that for some reason had no hole in the bottom, but was just a flat surface. I placed that in the probe and re-calibrated the probe length, then measured all the tools.

This method was kind of a pain because of having to change the tip and re-calibrate twice. My plan is to find either a disc probe tip that small enough for every day use, or a non ruby tip that I can grind a flat on the bottom of, then use for normal probing.

Terry

[kstrauss]

Just thinking aloud...
How about making a small disk of aluminum or whatever and resting it on the top of your endmill? Other than ball endmills most endmills would be easy to balance a disk on top of. You obviously need to compensate for the thickness of the disk but that is simply a constant.

[MFchief]

For some things that would fine, I believe, but for others it could be a problem, things like the super fly and 2 flute endmills would be tricky. Spot drills and other single point tools would not balance and you would have to hold the disk, keeping it level enough to not get a false hit would be hard because it takes an incredibly small force to trigger the probe.
Terry

[oneineight]

I think your idea is sound.
Measuring tool length with the height gage and holy granite block might be more consistent if, you always applied the same amount of pressure moving the height gage down to the cutting point.
I find that pretty difficult, but have been overcoming by taking several measurements until hitting the tool with just the right feel.

The machine would always use the same feel.

[kstrauss]

For some things that would fine, I believe, but for others it could be a problem, things like the super fly and 2 flute endmills would be tricky. Spot drills and other single point tools would not balance and you would have to hold the disk, keeping it level enough to not get a false hit would be hard because it takes an incredibly small force to trigger the probe.
Terry

Further thinking aloud after too much grape juice:
How about a parallelogram mechanism that would rest a disk on top of the tool/ drill/ flycutter and hold it parallel to the table and then use the probe on the top of the disk? There is always the Tormach 31875 for only $862.40.

[Hirudin]

How about just putting an M4 flathead screw in the probe with some kind of flat disc glued on it?

Or one of these with the head cut flat...
https://www.amazon.com/SOLID-BRASS-M...brass+m4+screw

[extdrive]

The wildhorse probes come with a flat aluminum disk attachment to do just that. I've not used that attachment though so I can't comment on how well it works.

[MFchief]

The reason for a disc or modified spherical tip would be so that I could leave it in the probe all the time to still do normal probing, not having to change it out to do the tool lengths. Hopefully in the future it will only be one tool at a time, maybe a replacement endmill or a new tool.

[handlewanker]

Hi, as I'm new to this game and I need to know...... I bought a Z axis setting block with a dial indicator for readout to give me a 50mm height above the table.....pic attached......is this method setting with the tool in the spindle the same as setting the tool with the probe out of the machine ?

BTW....just had a look at the setting block....it has two magnets in the bottom face........this makes it possible to stick the block against the vice fixed jaw side or face and get a precise reading for the X and Y zero.
Ian.

[Steve Seebold]

Now for something completely different. LoL

I have always used the granite block with a hole in it, with a height gauge to set my tool offset lengths, but I've never been too happy with it. I always seemed to get slightly different measurements every time I checked a tool, not a lot, but enough that, like I said I wasn't happy.

Then it occurred to me that I have a digital probe, so I place the small Tormach granite block on the mill table, zeroed the probe there and then used it to set the lengths of all my tools. I found most of them were slightly off, usually a thou or two, but some were significant errors.

Of course the problem with this method it that most probe tips are spherical, making it hard to get an accurate trigger. I happened to have a Renishaw break away section that for some reason had no hole in the bottom, but was just a flat surface. I placed that in the probe and re-calibrated the probe length, then measured all the tools.

This method was kind of a pain because of having to change the tip and re-calibrate twice. My plan is to find either a disc probe tip that small enough for every day use, or a non ruby tip that I can grind a flat on the bottom of, then use for normal probing.

Terry

You can get flat tips for those indicators.

I have never used the tool library on my machine. I always work from the offset page.

[MFchief]

I have never used one of those, but it looks like it would work similarly to the Tormach method of putting a dial indicator in the spindle, just kind of upside down maybe??

Steve, I couldn't find any flat ones in the Renishaw catalog, except to the disc with roller type. Do you know another supplier that carries them?

Terry

[Steve Seebold]

I have never used one of those, but it looks like it would work similarly to the Tormach method of putting a dial indicator in the spindle, just kind of upside down maybe??

Steve, I couldn't find any flat ones in the Renishaw catalog, except to the disc with roller type. Do you know another supplier that carries them?

Terry

Check out Q-Mark Manufacturing. They will make a probe in any configuration you need. They might even have what you want already on the shelf.

[MFchief]

Thanks Steve, they have a nice catalog, probably be ordering from them. I didn't see any flat bottoms, but they do make custom tips, as you said.

Terry

[MFchief]

I wanted to update this thread to let everyone know how it's working out for me.

I was unable to find any flat bottom spherical styli in any of the catalogs that I found, some companies offer custom stylus manufacturing, but I didn't inquire because I felt it would be too expensive for a hobbyist.

BUT, through the incredible generosity of a fellow forum member GLCarlson, I now have a 5mm diameter Renishaw stylus with a flat bottom. He and his spouse were able to grind the ruby tip flat on the bottom for a diameter between 3 and 4 mm. This give me the flat I wanted for tool setting and still has the 5 mm sphere shape for general probing work. The probe tip is nicely ground and polished,and very flat and perpendicular to the Z axis.

I've tried it out today and it works great. The most important thing about doing tool offsets this way is the repeatability. Since the probe triggers automatically and consistently, multiple measurements of a tool all give the same length. There is a much lower change of human error. This is especially critical to the very small tools such as the 2-56 thread mill I recently bought,

Thanks again to GL and all the members who took part in this discussion.
Terry

[Gilmax]

I have always used the granite block with a hole in it, with a height gauge to set my tool offset lengths, but I've never been too happy with it. I always seemed to get slightly different measurements every time I checked a tool, not a lot, but enough that, like I said I wasn't happy.

What brand height gage are you using?

[MFchief]

I have an no-name Chinese digital gauge and a Fowler double post mechanical gauge.

Terry

[MFchief]

So, just to keep flogging this horse, and since it's a slow weekend here in the forum.........

After I started using this method to set tool lengths, I was thinking this is similar to using the electronic tool setter that Tormach sells. So I experimented with placing the probe into the 3/4" hole in the small granite block on my mill table and trying to use the electronic tool setter screens. I knew the tool setter had a fixed length of 80mm but you can change that on the probe/ETS setup screen, so I set it to my probe length, then typed in tool 0 and used the probe in the block to set zero on the face of the spindle. I then put in a tool, typed in the tool number and selected set tool length on the offsets page. It all worked perfectly.

Now before actually setting the spindle zero and tool lengths I did some checking with my finger to make sure the probe would trip properly. And it is nowhere near as convenient as the actual tool setter because of the small size of the probe tip compared with the top of the tool setter, much more fiddley to get positioned under the lowest point of a tool, but if you have an active probe, and want to do this, it works and will save you 800+ bucks.

Terry

[Steve Seebold]

I have never used the tool library. I like my tool offset number to coincide with my tool number.

I like to use "T1 G43H1", T7G43H7 and so on.

I don't care for the idea of using T1 G43 H51 (example only).

[popspipes]

Now for something completely different. LoL

I have always used the granite block with a hole in it, with a height gauge to set my tool offset lengths, but I've never been too happy with it. I always seemed to get slightly different measurements every time I checked a tool, not a lot, but enough that, like I said I wasn't happy.

Then it occurred to me that I have a digital probe, so I place the small Tormach granite block on the mill table, zeroed the probe there and then used it to set the lengths of all my tools. I found most of them were slightly off, usually a thou or two, but some were significant errors.

Of course the problem with this method it that most probe tips are spherical, making it hard to get an accurate trigger. I happened to have a Renishaw break away section that for some reason had no hole in the bottom, but was just a flat surface. I placed that in the probe and re-calibrated the probe length, then measured all the tools.

This method was kind of a pain because of having to change the tip and re-calibrate twice. My plan is to find either a disc probe tip that small enough for every day use, or a non ruby tip that I can grind a flat on the bottom of, then use for normal probing.

Terry

I have found that if I touch off the tool with the same pressure and approach speed, bring it down to the tool and use light finger pressure the readings tend to be more accurate.
I have also found that the ambient temperature plays a part too.

For the stuff I do its not a real problem, just have to keep in mind where the idiosyncrasies are.

[MFchief]

Steve, I'm not tracking with what you are saying. In the tool table each tool, of course, has it's own number, and in the g code you would have that T number with the equivalent H number, how do you get in the situation of your example with T1 and H51?

Terry