I "almost" Bought a New Rotary Table

Could if be split into two pieces? You're kinda planning to work on it anyway...

Its an old beater, but the table top doesn't have to many apprentice marks. Vendor called me and told me shipping would be more than I paid for it, and asked if I wanted to cancel. Very nice of him.

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The second hand rotary table I bought was available because the table gear machining wasn't centered, if the worm eccentric was adjusted to pass the tight area there was noticeable play elsewhere. That wasn't evident until after disassembly and cleaning to free everything up.

I'm probably going to wait until I am a little more cash flush and just buy a new one.

I already have a 4" with a small chuck fitted for small stuff, a 6" CNCed for the Tormach mill, several spin indexers which I used for indexing 4th axis parts manually before getting the 6" CNC table, and a BS-0 size indexing head for "precision" indexing.

I can get by without it for most things, but something in the 12 inch or larger range would add some capability. I could make certain types of molds larger than the working envelope of my machines without re-indexing. Of course I make molds larger than my machines now, by moving them and reindexing them. I've built some fixtures with that in mind to achieve minimal loss of relative position.

I also have the obligatory collet blocks for quick 4 and 6 side indexing small parts in a vise.

My main reason for posting was I was totally stunned by the price gouging scam from the freight quoting services.

Which one, and how do you like it?

I don't recall. It was dirt cheap. I made a mounting plate for the chuck I took off my Harbor Freight lathe.

I don't use it often enough to really say if its any good, but it has done the jobs I have asked of it. I use the CNC table (from Tormach), the cheap spin indexers, and even the collet blocks more often. A lot of the jobs I would have used it for are easier now with other tools. I've been debating taking the chuck off to use on the 5C arbor Snag sent me.

I may have a job coming up for the BS-O indexing head. Resizing a bending die.

I may have a job coming up for the BS-O indexing head. Resizing a bending die. Bob La Londe

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Its center bore is likely 7BS taper, for which collets are still available, the drawbar thread is 3/8-16 like 2MT. You can use them with a shop made centering plug to accurately center a gear blank etc on a faceplate without fuss.

That's good to know. I'll read the manual to see if it says for sure.

Mine came with a 3 jaw chuck mounted on the face. It's probably good enough for a bending die. I'll turn an arbor with a center on one end. Press or machine (depends on what I have handy) a shoulder on the arbor, thread the outboard end, slide the bending die on the arbor, and cinch it in place with a nut with either a machine grooved thick washer or something similar. Then I'll support the outboard end with the included tail stock.

My Tormach CNC rotary has a morse taper center. I mostly use it with a collet chuck and the matching tail stock. I've thought about using it to make a 4 sided tombstone to cut more parts in a single load, but I'm not sure I'd gain much with the loss of z height and clearance needed for rotation.

I've learned to put up with old machines that are a little odd, and they likewise with me.

Yep, the documentation says BS #7 taper. Not sure what I would use it for, but I may pickup a set of collets in that size "just in case" at some point when I have a pocket full of money and nothing better to spend it on. Or I may see how much work it might be to convert the 3 jaw it came with into a Set-Tru style... or swap it out with a 4 jaw.

Given the largest BS7 in that set you linked to is only half inch, your improvised Morse Taper solution was probably more rigid than a boring head with a half inch shank.

I don't actually own a boring head myself. If kinda round is good enough CNC generally gets me within half a thousandth or round, and lots of things are made more than round enough easily enough on one of the lathes, but every once in a while I tell myself something would be easier and faster on the manual mill with a a boring head. I'll probably buy a cheap one with an R8 shank at some point, and then complain that I didn't buy a good one.

I bought the cheap BS-0 almost a year ago, and just took it out of the box for the first time this week. I haven't fully tested it, but generally look, feel, and basic function is much better than I expected. It does not look like a cheap import tool.

Yep, the documentation says BS #7 taper. Not sure what I would use it for, but I may pickup a set of collets in that size "just in case" at some point when I have a pocket full of money and nothing better to spend it on. Or I may see how much work it might be to convert the 3 jaw it came with into a Set-Tru style... or swap it out with a 4 jaw.

Given the largest BS7 in that set you linked to is only half inch, your improvised Morse Taper solution was probably more rigid than a boring head with a half inch shank.

I don't actually own a boring head myself. If kinda round is good enough CNC generally gets me within half a thousandth or round, and lots of things are made more than round enough easily enough on one of the lathes, but every once in a while I tell myself something would be easier and faster on the manual mill with a a boring head. I'll probably buy a cheap one with an R8 shank at some point, and then complain that I didn't buy a good one.

I bought the cheap BS-0 almost a year ago, and just took it out of the box for the first time this week. I haven't fully tested it, but generally look, feel, and basic function is much better than I expected. It does not look like a cheap import tool.

I don't actually own a boring head myself. If kinda round is good enough CNC generally gets me within half a thousandth or round, and lots of things are made more than round enough easily enough on one of the lathes, but every once in a while I tell myself something would be easier and faster on the manual mill with a a boring head. I'll probably buy a cheap one with an R8 shank at some point, and then complain that I didn't buy a good one.

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I need the boring head for things that are difficult to mount or too big to do on the lathe, flimsy project boxes and electronic control panels. CNC could handle some if I had it. The most demanding job the boring head did was reboring the end plate of a hydraulic gear pump for a new custom bushing, apparently it was slightly misplaced in the factory and then assembled without locating dowels so it could self-center, but it shifted and jammed when loaded. That's my guess, by the time I had diagnosed why it jammed I had done too much to return it, and I had this nice new-to-me knee mill begging like a puppy for attention...

Naturally I had no dimensioned drawing to go by but could clamp and center the other end plate and then dowel them together to match the locations. I found that raising the knee gave better accuracy than extending the spindle. The dowels are tubes that the assembly and mounting bolts pass through.

That repaired pump has run my log splitter every year since the 90's. The pump is in good company, everything else on that thing has been repaired or replaced. The engine was brand new with a leaky carb float. To top it off it had flipped and dragged while being towed. Yet it didn't cost that much to restore, and I learned how.

That makes sense if you have a tilting head on your mill. Its very difficult to get the head perfectly trammed so you see no movement over five or six inches of quill travel. In addition The quill may have more flex or side to side (and front to back) movement when not clamped.

When you crank up the knee it remains as perpendicular to the X/Y as it can be, but be aware that some knees have noticeable sag when they are not clamped or are not perfectly adjusted.

In regards using the quill with a not perfectly trammed head, you get a bore that is round, but at a slightly angle from perpendicular. (Other issues not with standing.)

In regards to using a knee with a not perfectly trammed head, you get a perpendicular (again other issues not withstanding) hole that is a slight oval.

In many cases I've found having the gibs, locks, etc dragging slightly helps with the "other issues" but accelerates machine wear (over years not days) by taking out travel surface backlash.

I am 100% aware you probably know all of this. I'm not trying to talk down to you, but reinforcing the concepts in my own amateur hack professional shade tree machinist mind.

I've found no matter what I do I get the best results by taking test cuts and measuring and indicating before taking finish cuts. Of course indicating is also thrown off by the issues with the machine, so indicating with two different forms of movement can sometimes show you the differences.

Most of the time I shoot for "good enough." Good enough was one of the hardest things for me to learn in machining. As a contractor I used to tell my technicians, "If you have to ask if its good enough it probably isn't." Ask yourself instead, "If Bob comes out here in a bad mood and inspects my work is he going to ask me to do it over," and "Never ask me if your work is okay in front of somebody else unless you are prepared for me to tell you in front of them." Good enough is a very difficult skill to master.

Most of the time I shoot for "good enough." Good enough was one of the hardest things for me to learn in machining. ... Good enough is a very difficult skill to master. Bob La Londe

--------------------------- I fully agree. When it matters I go by the assembly feel of sliding, light finger, heavy hand or press and try to reconstruct the tolerance afterward. It doesn't help that my machine tools have >60 years of wear and the vernier instruments I have to measure ID and OD to 0.0001" have different feels.