Thread: Micrometer Travel Stops

G'day Bob,
With regards to micrometer stops on a lathe, I never really saw the value in them and always thought they were a bit of a gimmick (of course this might just be because I don't own one).
If I need to set or adjust a stop accurately I use an indicator to determine the initial position of the saddle, move it as required then adjust and lock the bolt on my normal stop. To check it, I just move the saddle away and back against the stop and verify with the clock that it repeats where I want it.

Granted this is a bit more fiddly than just twirling a thimble but I don't have to worry about damaging a petite micrometer head and perhaps more importantly, the accuracy is not dependant on a micrometer which is constantly exposed to collisions with the saddle.

Perhaps an idea might be to make a holder for an indicator that could be positioned behind the hard stop and bares against the end of the stop bolt itself, this would allow you to see immediately if the stop moves while insulating the precision bit of the arrangement from any direct impact. Of course this setup would require more space which might be at a premium, that's why I haven't made one up for my lathe yet, although they are on the to do list for my mill.

P.S. I love your little mill stops and might just have to steal your design when I get around to making some for mine.

Cheers,
Greg.

Some good ideas there Greg. Thank you.

The indicator is something I should have thought about as an option. I had thought and done something about a similar setup for the 13 -



An indicator with a rubber boot on its stylus is probably a lot more impervious to the damage caused by grit that a dainty or oily micrometer.

More to ponder.

BT

https://www.woodworkforums.com/showth...20#post1370920

Bob, is it worth doing something like this?
stop.jpg
The dial coupled with the micrometer head should allow you better visibility and allow you to slow down in time. (I've half made one of these but am yet to put the graduations on the micrometer barrel). I have the appropriate taps (metric or imperial) if you want to make up the micrometer bit.

The other possibility is a damper of some sort (fluid filled). With the right needle valve you should be able to adjust it so that by the time it gets to the micrometer it has very little energy left.

Michael

Incidentally, in post 3 you linked to another thread where you contemplated making some extension pieces for your DIs but did not because you didn't have any M2.5 taps. I bought a tap and die in this size some months ago to repair an insert holder. If you think they would benefit from a small holiday let me know.

Michael

Originally Posted by Michael G

Incidentally, in post 3 you linked to another thread where you contemplated making some extension pieces for your DIs but did not because you didn't have any M2.5 taps. I bought a tap and die in this size some months ago to repair an insert holder. If you think they would benefit from a small holiday let me know.

Michael

The damper sounds like neat idea Michael.

I must have acquired an M2.5 tap and die because I did end up making an extension. I had long forgotten about their existence until the other day when I made an elephant's foot for my Compac. It's funny how looking for something can become a voyage of discovery, finding stuff you'd forgotten you had.

Bob,

As you have said, I had other grinders including 3 other T&C grinders. The Kao Ming, Makino C40 knockoff, had a ball race table like the Hercus but it had spring cushioned stops. The only time I could have done with a micrometer stop was when cylindrical grinding a shaft with a shoulder which then had to be faced. For the normal run of cutter grinding the table stops sufficed.


I got my container over at last and my gear into the new workshop, a lot of sorting out to do before swarf can be generated. One job will be to resume the resurrection of the Cincnnatti Monoset, quite a lot of scraping to do!

Normal micrometer heads are not strong enough to deal with the impact loads a tool and cutter grinder can impart

I pirated some off a lathe that was being scrapped and a tool and cutter grinder as well they are so heavily built in comparison

Bruce

Originally Posted by Aussie Bruce

Normal micrometer heads are not strong enough to deal with the impact loads a tool and cutter grinder can impart

I'm not so sure about that.....

Having said that. As yet, I've not been able to bring myself to use one as a lathe stop.......... even though one was supplied free of charge for that express purpose (which also doesnt please me)

Given I can't imagine ever wanting to dial on 1/2" of feed o the nearest 1/10th. Much more likely you'll want to dial on something less that 0.004"/0.1mm. Wouldnt any old normal thread, say 1mm pitch for the metric inclined be "close enough" over the distances we're likely to be talking about?

I believe the name of the device Micheal is talking about is a dashpot. I doubt any that I've seen on carbys would be big enough, but then I've never tried.

Stuart

Hi Bob,
As it happens I have a AI Hembrug universal grinder and it's documentation.
The standard stops are spring-cushioned but have a threaded (m8x1mm) bolt to "fine tune" the setting. There is also a real micrometer stop for this machine. These machines were not designed and built on a small budget, so I am sure both types of stop will prove strong enough.
I have taken some pictures of the manual parts and the standard stop.
I also have one micrometer stop somewhere. If you are interested I will try to locate it and take it apart for a picture.

Peter Heutsuploadfromtaptalk1425047510049.jpguploadfromtaptalk1425047579188.jpguploadfromtaptalk1425047625301.jpguploadfromtaptalk1425047680857.jpguploadfromtaptalk1425047821962.jpguploadfromtaptalk1425047910311.jpguploadfromtaptalk1425047998418.jpg

Thank you very much for the dissection Peter.

Correct me if I am wrong but the set screw E076915 is used to lock the plunger and override the spring. Neat. And simple.

If the micrometer adjuster availed itself for photos I would love to see them. I and I'm sure others would also like to see some images of the Hembrug grinder.

Bob.

Bob, you are right about the function of the big setscrew. The small one rides in the groove and limits the travel of the plunger. I will search for the micrometer stop and post pictures.
I will also post some pictures of the grinder in a new thread. I will post here if I have.

Regards, Peter

Bob,
I found the micrometer stop.
uploadfromtaptalk1425153564118.jpg
It's the bottom one. The top one is another incarnation of the normal stop.
I have taken it apart:
uploadfromtaptalk1425153713950.jpg
uploadfromtaptalk1425153874417.jpg
uploadfromtaptalk1425154108792.jpg
uploadfromtaptalk1425154196349.jpg

The micrometer stop is quite similar to the ordinary stop. The thread pitch is 1 mm with a diameter of 10 mm. The part just below the micrometer head is a bit bigger diameter. The micrometer head (diam. 20 mm)is divided in 100 divisions, which gives 1mm per turn and 1/100 mm per division. The extra screw is to fix the micrometer head to avoid losing your setting.

A drawing with sizes is probably not needed, because of the different machine you have, but feel free to ask anything if you want to know more.

Regards,
Peter Heuts

Hi everyone,
I promised to show some pictures of my Hembrug universal grinder. I have started a new thread for this:

https://www.woodworkforums.com/f65/ai-hembrug-universal-grinder-192936
AI Hembrug universal grinder

I look forward to your replies!

Peter Heuts

Outstanding Peter. Thank you.

I imagine the graduated collar is screwed in close to the line marked on the sliding piece 075848 to enable reasonably accurate readings ?

Bob.