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Putting right my tailstock DRO.
bogstandard:
Now onto the build back up, and this might be interesting for those of you who are contemplating fitting DRO's at some time in the future. Not onto the tailstock, but general information about fitting them.
As you can see, I have screwed the glass scale (GS) and the read head (RH) back onto the new slide, but this is a long way off being useable. These DRO systems do need to be set up very accurately to get long life and accuracy out of them. I have physical edges that were realigned between the GS and slide so that I know it is running perfectly parallel to the ram. Normally you have to use a DTI to get either the GS or RH running exactly in line with whatever axis you are fitting it to.
You have a choice when they are fitted, you can have the RH moving with the axis, as I did on the Z axis of my mill and the GS is fixed to the machine. The other way is to have the RH fixed and the GS moving, as in this setup.
So now back onto this setup.
When they are bought, the two parts usually come joined together with transit clips. So always save them, just in case you have to do something like I am doing, or they have to be returned to the supplier for checking or repair. Without them, there can be very serious damage caused internally to both parts, so they should always be in there and are the last things to be removed before turning on. They also act as setting guides, I have found that in this fixed position, if everything is fitted around them first, the gaps are perfect for normal operations.
The RH has to be set so that it never reaches the ends of the GS, so if you look very carefully, there is an arrow on the centre of the RH, and two dots machined into the GS. The arrow should NEVER go past either of the dots. Again, ignoring that can cause internal damage to the unit.
When you buy these scales, it is the distance between the two dots that is the read length, so as you can see, the GS are a lot longer than the actual reading length, and that must be taken into consideration when fitting them. The outer casings cannot be shortened in any way, as it contains all the electronical gubbins inside. DAMHIK.
So I have set up my combo with the transit clips and the RH well within the 'dots', even when the GS is in the fully forwards position. Only now can I think about getting the RH clamped down.
I will be able to utilise the top piece of ali, but the other part of the holder will have to be remade.
So a quickie machine up of the one under the RH, and I also made a new one to clamp down to the tailstock. These two need to be joined together.
More boring machining piccies.
This one shows the use of the edge finder and vice stop to get the holes where I wanted them. The holes are unique to every individual fitment, and can only be determined by fitting it to your machine and measuring up.
The holes being drilled. Do the first, then flip it over to do the second keeps everything nice and symetrical.
The same method was used for the bottom block.
These are the two finished blocks. All that needs to be done is the larger one has to have the four corner holes tapping out to accept long flat faced grub screws. They are needed to align the block onto the uneven surface of the painted tailstock before it is tightened down.
These bits now need to be refitted and the location holes drilled.
That is the next part of the saga.
Bogs
bogstandard:
I managed to grab a couple of hours quiet time to myself, so I took the opportunity to finish this part of the post off.
Now that I had the holes in the top mounting plate, it could be bolted onto the RH and then the bottom plate positioned where I wanted it.
It was then a matter of hammer tapping the hole positions thru with a transfer punch. The bottom plate was then drilled and tapped to take the joining screws.
So now having the final position of the bottom plate, I marked up where the jacking screws were situated.
Now comes the time to upset people you don't really like.
Go around to your neighbour and ask to borrow his sharpest brown stuff chisel.
Then take it and duly hammer away thru the paint layers until you hit base metal. Then scrape the surface well to get rid of all the paint.
He will really thank you for what you did to his chisel, and if you are lucky, he won't talk to you for months, or until he wants another job doing.
You need this area for the jacking screws to sit on. If you dropped them onto the paint alone, it won't have enough strength to keep all the work you have done stable. It would be rocking about in no time.
So now was the time to use the jacking screws to get everything perfectly set. It has a lot to do with feel.
As you screw them in, you will feel them touch the bare metal underneath, then it is a matter of individual tweaking to get the RH supported, but not moved out of the position that the transit clamps have put it into.
Once that stable position has been reached, it is then a matter of transfer punching thru the hole locations.
The marked holes were drilled and tapped.
If you do have the facilities to use a straight drill, then I find them much easier to keep the hole square when drilling vertical.
Maybe it comes from all the rivet holes I drilled on aircraft, I always found that the straight drills were the first ones to go out out of the tool cabinets. It also seems aircraft fitters prefer them as well.
Once it was all tweaked up and cleaned down, that is this part finished.
The next bit is to get this lot being moved by the tailstock ram.
I cannot use the original clamp, as it was made for a different location.
Bogs
bogstandard:
Now comes the real wing it bit, I have to make a fitting to go around the ram and then connect to the end of the slide I have made.
Up until now I have used metric measurements for what I have done, but because my boring head is imperial, the easiest way for me is to work in imperial for this one part.
So after a quick measure up, I did a sketch that would get me in the ball park. Then after that is done, I will trim it down to final shape. The piece next to the pad is the original, so as you can see, it is nothing much like the one I am going to make, except for the slot and big hole.
It didn't take long to get it scratched out on a piece of ali 1/2" plate.
It didn't take much longer to hack it out on the bandsaw.
Unfortunately, I have four sawn edges, so it cannot be held safely in a horizontal position in the mill vice.
That was easily remedied by flycutting two opposing edges parallel to each other.
Now it could be clamped safely in the vice, the backstop and parallels came into action again. The backstop was a safety precaution, to be able to take the part out of the vice and be able to reposition it again if it wouldn't fit the ram.
The centre of the circle was zeroed up and X & Y axis were locked up solid.
By going up in a couple of stages, I managed to get a 1" drill thru it.
The boring head was now swung into action and the hole was gently opened up to size. It really is a treat to have power feed on the Z axis, it was just a matter of putting on a cut, a quickie spray of WD40, then flick the handle and park my bum while it did the work for me, both up and down.
I was soon out to the required measurement of 1.258" plus 0.002" for clearance.
It fitted perfectly, so the backstop wasn't required, and it looks like I did something right for a change.
It was now getting towards sleep time for me, so I called it a day.
For the next exciting episode, tune in sometime soon.
Bogs
Andy:
Fascinating stuff. Learning all the time from your projects. Looking forward to seeing the end result.
Andy
bogstandard:
I'm glad it is being of help Andy.
It shouldn't be too long now, I have to get it finished soon, as I need to use the lathe and tailstock in anger.
Bogs
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