Rong Fu Clone (HF33686) head movement question

Good advice again - I would probably just create more problems if I used a torque wrench. Of course, with your design I could always just take off the backer nut on the other side and then unbolt the whole thing without the pain I just went through.
 
There must have been someone at the factory that specialized in cross threading those bolts, The top one on my new to me machine is locked on as surely as if was welded. I'll give it another try tomorrow with the impact but I suspect I'll need to cut it off there with a cutting disk.

John
 
Mine are working out just fine. I am now working on a power head lift motor and after that will endeavor to build something to "keep the x" while moving the head up and down. I wonder if when both such systems are in place the locking nuts become irrelevant or not. Sure would be nice to just take that step out of the process....
 
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Here's my take on keeping the x, something I had no issue with in the 12 years that I used my Rong Fu. It's a simple trick called a datum. Here's what you do- pick a spot on your table, vise, or whatever can be traversed under the spindle. Take a spotting drill and punch a dimple in that spot. Say it's the frontmost right hand corner of the jaw closest to the operator's position. Before changing a tool, traverse the datum (dimple) to align with the spindle. A pointy tool in the spindle helps. So you're aligned to that spot, your DRO says what it says for that datum. Now raise your head and change your tool. Lower the quill to point the tool into the dimple at the new head height. Tighten the head. Now you're aligned, and you pick up where you left off with your DRO.

Does it make sense why I grumble over some of the complicated fixtures for maintaining zero (play, backlash, and all)? I've seen some nice ones, we have one amazing example here, but it simply isn't necessary. You'll get better alignment from a datum.
 
That Lazy Machinist has a video on what John was describing. I watched it again last night. I use a DI on a magnetic base to bring the head back to where it was.
 
Here's my take on keeping the x, something I had no issue with in the 12 years that I used my Rong Fu. It's a simple trick called a datum. Here's what you do- pick a spot on your table, vise, or whatever can be traversed under the spindle. Take a spotting drill and punch a dimple in that spot. Say it's the frontmost right hand corner of the jaw closest to the operator's position. Before changing a tool, traverse the datum (dimple) to align with the spindle. A pointy tool in the spindle helps. So you're aligned to that spot, your DRO says what it says for that datum. Now raise your head and change your tool. Lower the quill to point the tool into the dimple at the new head height. Tighten the head. Now you're aligned, and you pick up where you left off with your DRO.

Does it make sense why I grumble over some of the complicated fixtures for maintaining zero (play, backlash, and all)? I've seen some nice ones, we have one amazing example here, but it simply isn't necessary. You'll get better alignment from a datum.
What do you do when you run out of Z?
 
What do you do when you run out of Z?
Buy shorter tools and tool holders? Kidding! (but not really).

I think you're asking about what happens when you need to set the tool high up but too high for the quill to reach the datum. You could turn a long pointer and chuck it in an R8 collet. I know, drawbar, extra work. I can imagine turning a spacer that keys into the datum mark itself and is held square to the vise/table top that you could line up on, since z-axis zeroing doesn't matter here- that's determined by touch off of a feature on the part. A a better way to make a datum is to make a plate with a nice dimple in it out of steel with countersunk bolt holes and a keyed bottom side to mount in an out of the way spot on your t-slot table. Or you could put it right next to your work during setup and get your location quickly.

I used to improvise the principle so that I wouldn't lose count on the handwheels when a height change would have to happen unplanned. I'd crank my way to any feature I could find on the table- a vise mounting bolt, the corner of a piece of stock, anything- and use that to index off of. Losing count on the handwheels isn't the end of the world, but it's nice to continue working quickly after moving the head.
 
What do you do when you run out of Z?

I use the longest tool method. Learned this from the That Lazy Machinist. I only use ER32 collets. Have never used a drill chuck. Drill chucks take up too much space and there is vey little wiggle room when changing tools. So far in the milling I have done the work is always held in the vise. A while back I got out the different tools I typically used. Took the shortest and the longest and after some fiddling got the head height set so that I could change from the longest to the shortest or vice versa without having to move the head. Since I did this I have not had to move the head to change tooling on a project. I know that there will come a time when I will have to move the head. When this happens I will use a DI on a magnetic base to bring the head back into position. I have practiced doing this.
 
All good advice - thanks. Sometimes the challenge of the modification project is the most enticing part - even when a simpler solution is present. Using ER32 collets and a vise I have rarely run into a major problem and if I had to "re-find" my position using an edge finder it is not the end of the world. I will give the datum method a go as I can easily set that in my DRO and get back to that spot pretty easily. I am not making parts for NASA so it ought to be just fine - and probably more accurate than some of the methods of keeping the X I have seen. Oh, but how I envy those with the space and funds for a proper knee mill....
 
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