Part 8- Cross Slide Drum
UNIVERSAL TOOL AND CUTTER GRINDER
Cross Slide Drum (CSD) PURPOSE:
- The CSD rotates on the top of the Index Drum. The rotation is perpendicular to the ID.
- This perpendicular rotation allows the the tool to swing in a controlled convex motion or set at a precise degree location.
- This Rotational travel may be controlled to swing between zero° to -90° or zero° to about -240°.
- The Graduated 360° Ring can be unlocked and reset to locate the zero° setting at any location. This will allow the user to set the 360° Ring to satisfy the requirements of the grinding job.
- The Index Head Base allows the CSD to be positioned, swinging or locked, in any rotational axis parallel to the Main Axle.
- The CSD holds the Top Slide and allows TS precision movement or locking on the X axis (left and right).
Removing the Cross Slide Drum:
Remove the two Jam Nuts on the CSD Axle. Remove the CSD Rotation Lock. It is easier to first remove the lever using a Phillips screwdriver and then a 12 mm nut driver. Take care not to lose the conical spring on the lever. The CSD should slide out of the Index Base.
The Screw that is marked with the red Ø indication should not extend inside of the Quadrant Ring.
Its purpose is only to provide a tab to allow the user to rotate the ring after it is loosened by the *Quadrant
Ring Clamp. If the screw extends into the ring it will bump against the Internal CSD Rotational Stop and
prevent full rotation of the ring and/ or the CSD.
To remove the Cross Slide Index Ring :
Back off the Quadrant set screw (photo # 003) that retains the Quadrant Ring Clamp Shaft
(I have replaced the Allen Head Cap Screw (AHCS) with a set screw and nut.This allow you to set and lock the screw in place).
Pull out the Clamp Shaft.
Pull out the Quadrant Clamp.
Pull the Quadrant Ring up and the clamp will come with it.
Cross Slide Drum Dovetail Way:
The top of the Index Head Assembly has a Dovetail or V-Way. This Dovetail Way holds the Top Slide and must work smoothly, just tight enough to have no play while in use but still move in and out. It should work exactly like the Top Slide of your Lathe.
There are two walls of the Dovetail, the Primary side and the Adjustable side. The Primary side is the most critical. The Adjustable side will conform to the Primary side using an adjustable Gib.
I applied bluing dye to Dovetail way to determine how much contact the Top Slide Dovetail had with the Primary side of the CSD. The match was pretty good but I did use lapping compound to smooth and improve it. This will at the same time lap in the Top Slide. Make sure all the lapping compound is removed when finished. Any left over compound will continue to remove metal.
(If the Dovetail Way appears to need more than just a little clean-up, do not work on
it until I go into more detail on repairs to the Dovetails and Dovetail Ways in Part # 010.
Skip to Problem with the Cross Slide Drum Axle:
There is no need to worry about how square the Dovetail Way is to the CSD because the Quadrant Ring can be orientated to the Dovetail Way.
I made a new Gib for the Adjustable side (see part # 010). The new Gib has relief or indent holes to capture the Gib Adjustment Screws to prevent it from sliding out when the Top Slide is adjusted.
Problem with the Cross Slide Drum Axle:
I reassembled the CSD back into the Index Drum and was very pleased with the modifications. The Axle had not wiggle and was snug but loose enough to rotate. When I tried to take it apart I found that the Axle would not slide out of the ID. Forcing it out I discovered that the CSD Rotation Lock Screw was not properly hitting the recessed area of the Axle and formed a burr.
I considered several fixes.
I considered removing the Axle from the CSD to turn it in the Lathe. Pulling out and pressing back in the Axle would be very risky. It is very tight and positioned in the CSD for just enough thread on the end to get the Jam Nuts on. I felt that there would be a high risk of cracking the casting, a part that is very likely not available. If you did crack the casing you could silver solder or braze it back together but the cast iron would very likely warp. The Axle may be glued in but I was not willing to risk any damage that may occur removing the Axle.
My lathe is too small to allow the entire CSD to rotate over the Ways and even if it would it would take some “very careful” counter-weights and/or slow rotation to turn the part.
For me, the best solution was the Milling Machine. I mounted the Axle in a rotating fixture (eg. Rotary Table, Dividing Head) and used a long end mill to reach the Axle Recess. I used my Universal Dividing Head with the Geared Handle to prevent the part from grabbing out of control. The Axle is hard but you can machine it. My CSD Screw just hit the edge of the recess so I added .125” to the recess length.
I used a two flute end mill (the only one I had long enough), but four or more flutes would be better, providing less chance for the tool to grab.
Bottom of the Cross Slide Drum:
I wanted more thread to extend from the CSD. I decided to machine a little off of the bottom. Be very careful not to take too much!!!!
Locating the Swing Rotation Center of the CSD:
(!!! this must be done after Dovetail Way Repair is completed)
I put this mod under the optional repairs however, one of the exciting functions of this tool is the ability to grind precision convex *radiuses. I needed a .500” Radius Lathe bit for a part I was making. This part had to perfectly mate with another piece. I was able to grind a perfect Radius on my lathe bit. The process took me several versions of the tool, so read the entire process and decide what is right for your machine.
A method is needed to allow you to determine where the rotational center if of the CSD from the top of the tool. You need this center point to grind accurate radius's on a tool.
Preparing the Cross Slide Drum for Rotational Center:
Measure the CSD Axle and select the same size Gage Pin or Dowel.
I used a 3-jaw chuck to hold and dial in the pin.
When the pin is properly located, remove it and put the CSD in its place, position the CSD inward on the Y Axis. the CSD V Ways should be parallel to the X Axis. Now center drill.
Zero your Digital Readout if you have one.
This next operation is necessary for all the Center Locating Tools
Find a small brass or copper rod; I used #14 copper wire. Measure the rod.
Move the mill table Y Axis outward, toward the CSD Dovetail .250”.
Then move the table ½ the diameter of the copper rod. For me it was .032" (.064" ÷ 2= .032")
Using a tiny center drill lightly mark the location of the copper rod.
Now the mill should be located so that ½ of the copper rod will be split when the ½” end mill does the cleanup cut at the end of the segment.
Drill the tiny hole for the brass rod, put a little super glue in the hole and tap in the rod.
This Places the tiny Brass Dot on the centerline of the .500” Diameter Landing that will be the last operation in this section.
Normal 0 Now bring the mill back to zero or Center of the CSD Axle.
MACHINING THE TOP OF THE CSD:
Drill a #19 (.166”) hole through the CSD casing. I was hoping to get more thread area but there was a gap then my drill hit the CSD Axle. The Axle could be drilled and threaded but for now I will only tap the CSD Case. It is about .200” of material.
Tap the hole with a 4.8mm in the mill to insure it cuts straight.
Use a ½” end mill, make a flat spot or landing on the top of the CSD. Only go deep enough to make the flat. I had to plunge in .035” to get thru the paint and bondo and have clean metal exposed.
All on the centering tools will use ½” Drill Rod.
A plug is needed to prevent grinding dust from getting into the open hole when the tool is not in use.
CSD Centering Tool #1:
Cut off 3” of ½” Drill Rod.
Chuck up the rod in the lathe.
Face, center drill and drill through with a #10 (.193”) drill.
This is the tool bottom so machine out some of the center of the rod to
ensure the outer perimeter of the rod provides a solid seating area.
Turn the part around and machine the end as needed.
Chuck the part between centers in the lathe.
With a sharp pointed cutter, drag a center line the length of the rod.
CSD Centering Tool #2:
While researching the grinder I saw a similar tool being used. I decided it was worth trying it for my article to see if would make the setup easier.
The post and the socket must be a “no wiggle” sliding fit to work properly. For the socket I drilled it undersized then reamed it. The final process was lapping it in to a perfect fit.
The advantage of this rotating tool is that it can bring the nose of the tool or/and the side of the tool to center.
CSD Centering Tool #3:
Setting up for cutting radius's will be covered in a later part.
The Cross Slide Drum and Top Slide Vernier Scale:
The Vernier scale, invented in 1631 by French mathematician Pierre Vernier
[Vair-nee-ay (as in “bay”)] (1580–1637) is a small, movable, graduated scale
running parallel to the fixed graduated scale.
Used for measuring a fractional part of one of the divisions of the fixed scale.
In the following, N is the number of divisions the maker wishes to show at a
finer level of measure.
The Vernier indicating scale is constructed so that when its zero point is coincident
with the start of the data scale, its graduations are at a slightly smaller spacing than
those on the data scale and so none but the last graduation coincide with any graduations
on the data scale. N graduations of the indicating scale cover N-2 graduations of the data scale.
If you need the have a precision method of moving the Top Slide you can
use a dial indicator or install a proper Vernier Scale.
Using a thin blade, remove the vernier scales on the Top Slide and the CSD.
Using the scale from a Vernier Caliper I replaced the scale.
A quadrant is an instrument that is used to measure angles up to 90°.
Terminology of parts Disclaimer:
Several names of the parts have been taken from the Deckel Catalog; to insure you the reader, will always know what part I am referring to. I have applied the identification of parts from other machines, catalogs and some I created for a clear description of the parts function, (eg. Top Slide Tool Holder).