Another DRO install

I have a Berco AB 320 at the shop. Dedicated connecting rod machine made in Italy , so i guess its allowed here.
At any rate this machine is used for boring either the big or small ends of connecting rods.
We do lots of white metal bearing work here owing to the age of the engines we work on.
Here is the machine...fairly simple, having a spindle and movable Z axis carrying a vertical slide that carries the rod.



One of the chores in finishing a connecting rod big end is finishing the width of the bearing faces to get the proper side clearance on the crank journal.

For years i have done this work using an indicator and magnetic base to gauge the actual travel of the slide and thus the material removed from the bearing faces.
This method worked, but was not the most reliable and it was time consuming.

Figured that perhaps there was a better way, and i remembered that i had acquired a single axis DRO on a little Myford grinder that i purchased years back.
When i rebuilt the grinder , i did not reinstall the DRO as it seemed unnecessary (was setup on the grinder Z axis.

At any rate i dug out the readout, blew the dust off and connected it to the wall power.....Cool. it works!
Not a new item, a bit shop worn and worst of all it had a membrane key pad on the box...my least favorite entry setup.

Decided to fit the repurposed box and scale to the Berco to read the position of the long slide.
I wanted to mount the scale on the opposite side of the machine from the controls, too much stuff in the way over there.
Problem was that the base was an unfinished casting where the sides sloped (draft)

Fortunately, i have a milling machine, so with a bit of work, removed the head stock, drive motor and electrics, vertical slide and separated the machine from its cabinet/base.
Next stop: Deckel FP4NC......



Base was shimmed and clamped to align the slide (Z) with the mill both horizontal and cross leveled....
The cross slide of the rod machine was fitted with an accessory mounting casting for gauging wrist pin boring, and that casting was going to be the mounting for scale read head bracket....

In the above shot i am milling the under side of that casting to create a flat surface using an end mill. I did not cut the full width of that casting , but rather left a raised island on the inside to act as a reference surface. Note clamps applied to the rod machine slide to hole it stationary while cutting.

The casting was removed for access, and spot faces were milled into the side of the rod machine base. All three spot faces were done by profiling to make flat faces , all done at the same depth and
further drilled and tapped in their centers w/M4 threads.
The spacing correlated to the mounting points for the scale.



The scale was test fitted using stand off's turned and surface ground to the same dimensions. The alignment was tested using the movement of the slide for vertical and horizontal alignment...

One of the advantages here was since the rod machine was on the mill, i was able to use the Deckel to accurately map the locations of all the critical points needed for fitting the scale and the read head.



Take note her of the scale. Bit different form most The scale is housed in a two part extrusion. the rear portion carries the glass scale. There is an outside portion that encloses the housing and is removable to allow easy cleaning of the scale...a nice setup IMO.
Note the three screws at each mounting point. The center larger Allen mounts the rear housing to the machine. The smaller screws on each side hold the outer cover in place. It is possible with this
setup to remove the outer covering with its seal without removing the scale from the machine....pretty slick. Further , the outer housing is sealed to the elements with an "O" ring.




Armed with required mounting dimensions derived from the scale position, i did a bit of design work and came up with a mount to go from the rod machine casting to the read head of the scale....
Then its a matter of some machine work......

More to follow:
Cheers Ross

With a design firmed up , machining the read head bracket:

V\

Nice to have 3-D contouring....Fun to make stuff that is more involved than just straight lines and square corners....
Note the holding fixture...It is a piece of the material that i blanked out to make the part. Drilled a hole at the intersection of a corner of the part, and cut the extra material off using the band saw.

Scrap was then surfaces and drilled for holding screws that threaded into the part. Those threaded holes will eventually be clearance reamed for bolts that hole the bracket to the rod machine casting....
Doing contouring, often you have to be careful of the fixture...here its consumable, so no worries.



Here the part has been turned over to finish the inside.........................



I needed to machine some features into the rod machine casting...Here i have the casting mounted to a 1-2-3 block held in the vise....I am using a through bolt and a clamp.
When buying 1-2-3 blocks always get the ones that have drilled through holes..



Here the reference surface is visible that i machined with the casting mounted to the rod machine slide.....

Here is a shot of the finished read head mounting bracket....I have it fitted up to the rod machine casting to verify its truth and spacing......Note the offset stepo on the inside of the bracket.
This is where the read head mounts and the offset provides clearance for the bracket to clear the scale.




More to follow:
Cheers Ross

Here is a shot of the scale with the outside cover removed for cleaning......prior to actual instillation.



OK so here is the installed scale on the machine.....
Of note, i milled flats on one side of all three scale standoffs and tapped an M3 hole in that flat.
This became the base for a sheet aluminum guard that covers the top of the scale to prevent chips from getting in behind the scale....The guard is held in place using button head Allens...





Final is to mount the DRO box.....

Pretty simple plate (aluminum) that bolts on top of the original spindle switch...






Cheers Ross

Nice work, Ross! I am a fan of custom mounting brackets for read heads rather than using "stock" L-brackets. But mine are square/rectangular and don't have the nice contouring that you did here.

When making DRO scale/head mounts, whenever possible I size the mounting holes to the screw ODs, leaving zero slop. This means that I can remove and replace the scale and head without having to realign each time. Here is one example:

Adding a digital read out (DRO) to a Logan 10" lathe

By the way, who is the manufacturer of the "openable" scale? I have not seen that before.

Cheers,
Bruce

Bruce:
All fittings here done with zero adjustment to any of the mountings....That is why things were gauged as to their truth when test assembled as shown above.

The maker of the DRO is " Futaba Pulse Scale"
Made in japan.....
Cheers Ross

Nice!

Semi related question: for white metalled con rods do you scrape the bearings after machining?

L7

No scraping of properly machined bearings.....I do cut in spreaders at the parting lines for all bearings both mains and rods.
Only scrape where necessary, such as the transition between the finished bore and the end fillet, sometimes you need just a bit of extra clearance where the fillet joins the straight bore.

I do scrape or break all edges such as parting lines and the edge of oil grooves and oil feed holes.
IMO bearing scraping is only used on new work when you don't have the machinery to do a precision finished bore, and hand fitting to the journal becomes the only alternative.
Cheers Ross

Nice.
From my cobwebs of strange, accumulated stuff:
Futaba means "Green Leaves". They used to make the green LED panels for SONY Betamax VCR's.
And they also make very good quality R/C model control equipment (what I use). Since the 70's at least.

Cheers
Erik

Here is the remains of the Futaba DRO's I had at one time.