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- Nov 2, 2013
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- 960
Yes, that's the only way.
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Clausing 8520/8530 Tramming
- Thread starter JPigg55
- Start date
- Joined
- Dec 25, 2011
- Messages
- 10,511
Yes, that is the only way that I know of. Note that an engine hoist will make this go quicker. I don't have a Clausing manual handy to to look at how that joint is held together but most of the possible ways to do it will require multiple shim thicknesses . For example, if the joint is made up from 4 bolts or studs in the flanges and if the bolts are front, rear, left and right, and the error is front low, left and right OK, then you will need one shim in front of thickness X and two for left and right of thickness X/2. For measuring for a front-to-back tilt assuming that you are using a standard dual-gauge tramming tool, first adjust the tilt and then notate the spindle 90 degrees CW or CCW to measure nod.
- Joined
- Nov 2, 2013
- Messages
- 960
During the measurements the table is stationary, and you are comparing one side of the table to the other, being high or low. In both the X & Y axis. If you completed the measures and any tram adjustments and then "tighten up" the gib screws, it could possibly change your readings. If you did make any change, you should re-do / verify the tram,,..
- Joined
- Nov 14, 2016
- Messages
- 2,999
Have you actually found that you are out of tram on the Y? Considering that the Y axis travel is only 5" you would have to be pretty out of whack to notice. I usually leave mine set up with the spindle on the center of the Y axis, which allows me to use the full 5" of travel in one direction or 2-1/2" in and out depending on need. On mine there was no detectable movement of the indicator moving the table in and out (Y) and by centering it I cut that undetectable deviation in half.
With a little practice I have been able to get the X down to less than .0005" over the whole 15".
With a little practice I have been able to get the X down to less than .0005" over the whole 15".
I have posted this on other sites so my apologies if you have seen it before but this is the first site I have run across specific to Clausing.
Following is a description of some tips and improvements for tramming a Clausing 8520 mill. This may work for other similar ones like grizzly G0696 round ram head mil or perhaps A1S mill-Drill units like HF 40939.
I found it most important to have the clamp bolts as tight as possible when adjusting the head, this reduces movement when it is finally clamped tight. I chucked up a drill rod and adjusted the clamping bolts (one at a time) to the point where I could just barely tilt it by hand then marked the bolts. At this point I found I could move the head with a long wood stick, prying the extended quill or motor mount against the mill column. This seemed a little more repeatable than tapping on the head with a plastic mallet.
There are lots of recommendations on the web for how to measure Tram, I used a DTI held in a collet and rotated the quill between 2 different 123 blocks. Start with the indicator just barely contacting the lower block, carefully rotate to the other block and move the head so the needle moves 1/2 way back to zero. It only took a couple of iterations to get the same reading on both blocks. I find it works best to tighten up the back clamp bolt first, then front. The DTI does still move a little as the clamp bolt is tightened so there might be some trial and error.
I decided to make a fine adjustment attachment for the mill. After a couple of quick calculations, I started with 1.125 shaft (actually annealed torsion spring from an old Astro van) and 2 ea 0.25" thick plates. I welded together then bored the 2.995 holes to fit the mill ram shaft. This took awhile, probably would have been quicker to grind a treepanning bit? I have used hole saws but they are pretty slow also. Even cutting
out most of the metal with a cutout wheel or torch might of been faster.
Next I welded on the other parts and fit a couple of 10-32 adjusting screws and sawed the assembly in half vertically. Probably should paint it but can't wait to try it out.
A little adjustment and it fits on the mill perfectly
The opposing adjustment screws made it very easy to adjust the tram. The adjustment screws are 6 in below the ram and offset from the center of the vertical bars by 2 inches. The thumb screws snug up but do not flex the assembly too much. If both screws are left snug there is little change in the tram as the ram clamp bolts are tightened. The entire tramming process took about 5 minutes not including photographs.
The entire assembly can be loosened and moved with one nut on the top (same nuts used in the mill table clamping kit). It can be easily removed or moved to the front of the column if more ram adjustment is needed.
There are a couple other things that can be checked. The above tram checks that the spindle is perpendicular to the table surface in one direction, it can also be checked front to back (nodding) but there is no easy adjustment on this mill (short of shimming or scraping).
The parallelism between the table top and bottom dovetails can next be checked by setting the indicator on the table (or a parallel block) and cranking the table in X and Y.
Deflection of the mill under load can be checked by using a fly cutter or large face mill and fine adjusting tram by trial and error to get the desired cross hatch pattern. If the pattern changes depending on cutting load or direction it suggests some deflection in the machine frame or spindle.
For years I have gone to every contortion possible to avoid changing the head because it was such a pain to get it trammed back in. I wish I had made something like this long ago. This tool only works when the overarm is reasonably parallel to the Y axis so if I need to rotate the top of the column I will set the overarm length and tram first, slide the adjustment tool off then rotate the top of the column. I kind of like the idea it does not require any modifications to the mill itself.
I am sure many others have done something similar but a search did not find any, (probably a good indication of my poor search skills) so I figured I would share.
Following is a description of some tips and improvements for tramming a Clausing 8520 mill. This may work for other similar ones like grizzly G0696 round ram head mil or perhaps A1S mill-Drill units like HF 40939.
I found it most important to have the clamp bolts as tight as possible when adjusting the head, this reduces movement when it is finally clamped tight. I chucked up a drill rod and adjusted the clamping bolts (one at a time) to the point where I could just barely tilt it by hand then marked the bolts. At this point I found I could move the head with a long wood stick, prying the extended quill or motor mount against the mill column. This seemed a little more repeatable than tapping on the head with a plastic mallet.
There are lots of recommendations on the web for how to measure Tram, I used a DTI held in a collet and rotated the quill between 2 different 123 blocks. Start with the indicator just barely contacting the lower block, carefully rotate to the other block and move the head so the needle moves 1/2 way back to zero. It only took a couple of iterations to get the same reading on both blocks. I find it works best to tighten up the back clamp bolt first, then front. The DTI does still move a little as the clamp bolt is tightened so there might be some trial and error.
I decided to make a fine adjustment attachment for the mill. After a couple of quick calculations, I started with 1.125 shaft (actually annealed torsion spring from an old Astro van) and 2 ea 0.25" thick plates. I welded together then bored the 2.995 holes to fit the mill ram shaft. This took awhile, probably would have been quicker to grind a treepanning bit? I have used hole saws but they are pretty slow also. Even cutting
out most of the metal with a cutout wheel or torch might of been faster.
Next I welded on the other parts and fit a couple of 10-32 adjusting screws and sawed the assembly in half vertically. Probably should paint it but can't wait to try it out.
A little adjustment and it fits on the mill perfectly
The opposing adjustment screws made it very easy to adjust the tram. The adjustment screws are 6 in below the ram and offset from the center of the vertical bars by 2 inches. The thumb screws snug up but do not flex the assembly too much. If both screws are left snug there is little change in the tram as the ram clamp bolts are tightened. The entire tramming process took about 5 minutes not including photographs.
The entire assembly can be loosened and moved with one nut on the top (same nuts used in the mill table clamping kit). It can be easily removed or moved to the front of the column if more ram adjustment is needed.
There are a couple other things that can be checked. The above tram checks that the spindle is perpendicular to the table surface in one direction, it can also be checked front to back (nodding) but there is no easy adjustment on this mill (short of shimming or scraping).
The parallelism between the table top and bottom dovetails can next be checked by setting the indicator on the table (or a parallel block) and cranking the table in X and Y.
Deflection of the mill under load can be checked by using a fly cutter or large face mill and fine adjusting tram by trial and error to get the desired cross hatch pattern. If the pattern changes depending on cutting load or direction it suggests some deflection in the machine frame or spindle.
For years I have gone to every contortion possible to avoid changing the head because it was such a pain to get it trammed back in. I wish I had made something like this long ago. This tool only works when the overarm is reasonably parallel to the Y axis so if I need to rotate the top of the column I will set the overarm length and tram first, slide the adjustment tool off then rotate the top of the column. I kind of like the idea it does not require any modifications to the mill itself.
I am sure many others have done something similar but a search did not find any, (probably a good indication of my poor search skills) so I figured I would share.
- Joined
- Nov 25, 2015
- Messages
- 8,284
no it does not.
as asked by someone else, do you have your knee gib tight? Have you tightened the locks?
I used a brass shim under my overarm mating to the column.
Have you put an indicator attached to the table, and a precision rod in a collet; raised and lowered the table, reading the bar. Then turn the rod 180 rinse repeat to make sure the rod is ok... and not loaded in the collet at an angle... if the rod does not read the same, then you need to reset and get the rod to read the same on both sides. Then check again...
This will help determine whether the problem is the knee or head.