Very nicely done and a great enhancement to the solid toolpost design! A few things come to mind that you probably already thought of. A 1/16' cross section o-ring as far out as possible on the underside of the toolpost disc. This will prevent coolant from wicking in allow vigorously blowing off the interface before changing angles. And engrave the 7.5 degree settings on the od of the disc. You could only do 90 degrees of divisions and put 4 index marks on the base. Excellent video and thanks for the mentions. ATB Robin
Nice job. In addition to Robin's suggestions, you might consider adding a counterbore around the stud and a spring fit inside it to lift the toolpost when you loosen the clamping nut. That will aid in keeping your upper ball seats in good shape for a long time. You could even get fancier and add a thrust bearing stack on top of the spring.
I see a lot of people making solid toolposts for small machines hoping for better rigidity but sticking out the tool to the left of the crosslide causing a lever/counterclockwise rotation force on the cross-slide and pulling the right gibbed way up. For maximum rigidity the cutting edge should be as close as possible or behind the left edge of the crosslide table, loved the offset on yours to address that, people often fail to see these basic lever systems/machine physics issues.
What do you think the feasibility of making those holes accurately manually with a rotary table. Mine has degrees and minutes on it (possibly seconds too). Was looking a Robs design but if I could pull an indexing option off that would be great
That is in fact the nicest version of the solid tool post i have seen yet, looks sleek and is packed full with great engineering trickery. For me the ball kinematics would maka a axa tool post viable, but since I am from europe and you almost exclusively see multifix holders, i won't have to go through the hassle ;) anyway, very very nice build
In Scandinavia and Finland we used most commonly some Swedish toolposts, I have 2 different brands, Toolfix/malcus and Bergström. Maybe in newer manual lathes the multifix is most common since the clones made it cheaper
Hello, Beautiful work. I would be very willing to pay for this tool post for my Hardinge lathe. Are you interested / willing to make one for my lathe? John
When you say "we", who are you talking about? Can you point me towards more channels and content? I love your videos but I keep feeling like I'm missing out on a lot!
Awesome as always. Great tool post and we’ll explained. I’d like to hear more about the theory of elastic averaging. You should present some of the theory behind precision machining. Would be interesting
Interesting idea although I don't find it a problem setting the Aloris back to parallel with the headstock after changing its position. I simply use a gauge block between the Aloris and the headstock. The other problem is the location of the Aloris on the cross slide. While there may be a degree of downward force that is transmitted to the cross slide with the Aloris mounted within its front ledge I think it is minimal. The downside is that the tool holder itself sits too far from the headstock. This isn't a problem with the extension of the three jaw chuck but with a collet chuck, at least on my lathe, the tool holder won't reach it for applications like cutting off where the benefit of the solid base is needed most. For this reason I've sacrificed the position of the tool holder as to not limit the functionality of the lathe which is already encumbered by the reduced versatility of the solid tool post.
The amount of friction force between the mating surfaces of your tool post and the support is going to be reduced by the amount of elastic deformation force caused by squeezing all of those balls. It seems that you want to rely on the shear strength of all of those balls instead of the friction force between the two parts to prevent the rotational movement of the tool post under load. If all you wanted to do was provide indexing for your tool post, then you really only needed one ball detent on one face and 48 corresponding holes in the other. Nearly all tool posts rely on the frictional forces between post members to prevent rotation under load. I suppose this will work, but it is far more work than is required in my opinion. Moreover, the fact that you put the tool post as far away from the spindle as possible means that you're not going to be able to work as close to the chuck as before. The workmanship is outstanding, far better than I can do, but without actual measurements showing actual deflection amounts, I wonder if it's overkill for this application.
Nice job! I have a question. How did you get the parting tool dead nuts parallel with the cross slide travel? The other tool types don't matter, as the tool itself can be moved within the toolholder. But the cutoff tool can not. Is there enough clearance in the mounting holes to the cross slide to allow tapping it in place parallel? Although with that 4th screw with the left and right hand thread, I don't see how that can move positionally?
There’s a bit of slop in this mounting screws, they can pivot around the differentially threaded one. There’s also slop where the tool post itself mounts to the plate with the ball seats. Between these two, there’s enough to tap it around and get it dialed in
Very clever and refined improvement on Robin's ( and before him other's) solid tool post - really good explanation of the 'extra' rigidity to be gained in use as tool forces 'ride' on dovetail of the slide. Thanks for posting - subscribed. Pete
Looks great! I can't quite visualize how being on top of the dovetail makes things more rigid, do you mind elaborating? Probably an over simplification: Seems like cutting moment will still rotate the system about the same midpoint (or wherever) both dovetails, assuming the saddle is rigid.
Up to you and your needs, elastic averaging will not be as high due to less balls. That and a smaller diameter circle will both result in requiring a higher degree of precision in the drilling of the bolt hole pattern to achieve the same accuracy. But this particular one was repeating to .8 arc second so probably overkill for most
Great adaptation of the solid tool post mount! Just one thing: since the tool post is now moved further inboard on the cross slide, I assume turning/facing diameters larger than will clear over the corss slide requires extra trool length sticking out of the holders to reach?
It looks like it can be turned around if you need to turn stuff bigger than what fits over the cross slide? That's why the tool is usually to the side of the cross slide and it works pretty well if the slide isn't super worn or unrigid
@@MF175mp if you're referring to the mating holes for the balls, they are relieved. and yes, if we need to turn something larger the the swing over the cross slide, we can just rotate the tool so that's its out over the side. However, its very rare we see work that big so I don't see it being much of an issue.
