Quick Change Toolpost question

Hello all:
About four years ago I bought a SB 14" which came with a Haidao 250-222
quick change toolpost, wedge type. What I know about QC toolposts is
what little I've been able to glean from ten minutes searching RCM
archives. So:
1. Where can I purchase additional tool holders? Preferably El Cheapo
brand, I'm not terribly picky. This is, presumably, a 200 series, and
other 200-series holders fit it, correct?
2. I seem to be having some difficulty with keeping the post screwed
down properly. At first there's about two threads that show above the
top nut. But as I loosen and tighten the nut to change the angle, the
threaded stud seems to work its way down, slowly. And it takes more
than a half-turn of the wrench to loosen the nut completely.
I've tried removing nut and the washer under it, and there is another
"nut" that appears to take a spanner wrench with about 1/8" tips (which
tool I do not have). I've tried tightening it with a makeshift tool
but it doesn't appear to have done much good. Do I need to get the
right tool and tighten the thing properly, or does the problem lie
Thanks for any help,
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That -- or BXA series (different maker, same sizes)
For that size, I would probably have selected the CXA (series 300) quick change toolpost, instead of the BXA (series 200). I selected the BXA (series 200) for my Clausing, which is a 12x24" machine, and am quite glad that I did.
Note that you can find the series 200 and/or BXA size tool holders from several manufacturers, and they will interchange on wedge-style toolposts. (Some have problems on piston style.)
How often do you do this? I normally set it so one dovetail is parallel to the spindle and the other parallel to the chuck face, and don't disturb it unless I have had to shift the compound. This position puts tools on the side dovetail in the proper orientation to turn the OD of a shaft, and tools on the inner dovetail in the proper orientation to face work in the chuck and to bore with a boring bar.
It also makes sure that carbide insert type threading tools are at the proper orientation to the workpiece.
There are tools available with differing insert angles, so you can simply change the tool (it *is* on a quick-change toolpost after all).
Also -- loosening, adjusting, and re-tightening the toolpost just to get other angles from the tools destroys the repeatability of the other tools. I depend on the tools retaining their position when I put them back on the post. (That is one reason for using indexable carbide inserts.)
The stud should be bottomed in the T-nut, if it can be without protruding out the other side and binding in the T-slot. If it won't bottom without protruding too far, unscrew it, clean with a solvent, hit with the primer, and put in a good strong grade of Loctite. This will keep it from wandering -- however -- usually it is the inner cylinder backing out which does this ...
A hinged pin spanner with 1/8" pins on the sides of the arms works quite well for the purpose. (The same one which I use for mounting grinding wheels on my tiny surface grinder.) These are available through MSC (and other machine tool vendors), or can often be found in eBay auctions.
For an example what to look for, check out auction #4361720105.
This one has 4mm pins, which are a little big (0.1575" instead of 0.125", but it might fit). Or you could file the pins a bit narrower to make it work.
You could also make your own by taking some 1/8" thick steel, cutting a half-moon with a notch to clear the center bolt, drilling two 1/8" holes, and driving two 1/8" pins into them to engage the slots on the top of the threaded cylinder.
Again -- this is another place for Loctite. unscrew it (it will be a cylinder with a flange at the top and a short threaded section at the bottom). Clean all oil off the threads in both parts. Make sure that the large threaded cylinder with the locking lever does not come out -- or if it does, make sure that both wedges travel through the proper range when you reassemble it. Then hit the threads on the bottom of the cylinder with some primer, put on a little heavy-duty Loctite, and reassemble with the pin spanner to snug it down. Wait a little while (perhaps an hour or two) before you tighten the nut which secures it to the compound, just to make sure that the Loctite sets properly first.
I've done this with mine (Phase-II brand) and have had no more trouble -- though since I shift the toolpost so seldom, I don't find it a real problem anyway.
You *can* undo the Loctite with applied heat, but it is better if you don't need to. :-)
Good Luck, DoN.
Reply to
DoN. Nichols
I have commented on this subject often and I still find it amazing that the mulifix toolposts used in Europe are just about unknown in North America. They are infinitely better than any piston or wedge Aloris type quick change toolpost, because the toolpost head is indexable every 15 degrees. They are extremely well made and always returns to the same place. Additionally, there are a large variety of different tool holders that are compatible and many of these are not available in the Aloris type holders, like camming toolholders for internal and external treading. An example can be found by doing a search for multifix in eBay.de. They come in various sizes ranging from Aa to Dd and each toolholder will have a number like AD25100. Where A = the head size, D = the tool holder type, 25 = the tool slot width and height and 100 = the holder length. As a rule of thumb the Aa size is for 7" machines, the A size is for 10 - 12" machines, the B size is for 13 -15" machines, the C size is for 16 -19" machines and the D for 19 - 22" machines. These are made in Germany, Austria and Switzerland by various firms like Haase and are usually compatible to each other. New, they are very expensive. They last forever and are available used at reasonable prices. I have used them exclusively for 25 years. Steve
Reply to
Steve Lusardi
Thanks a gazillion! Very useful information!! To answer a question, I shift the compound angle probably more often than most guys. 15 degrees for the exit cone of a nozzle for a rocket motor, then 45 degrees for the entrance cone. Material: Graphite, AKA "compressed filth"....
Thanks again -- P'rfesser
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