Howdy ya'll. I have a few questions regarding sweeping in a fixture we have mounted on our TL1 lathe carriage to mount a Nikken SK collet holder to then use for reaming. We made the hole on the fixture by center drilling, drilling, plunge milling at 1", then boring with an adjustable boring head to 1.235" and then reamed to 1.250" which it turned out over size by what looks like .0022" best we can tell.
Anyways... I currently have used two different .0005" graduation dial indicators mounted into the chuck with a Interapid test indicator holder (the kind that uses links with screws to tighten in place), and I am sweeping in the ID hole on the mounted fixture block. I have seen about .0015" out of concentricity in the "Y" axis (If using zero reference on bottom of hole then top of hole is showing .003" off the zero). Now I have noticed that any of our DTI's that I use don't repeat the best, and when I used a longer stem indicator with .0001" graduation just for the heck of it, it was showing .002" out of concentricity. I feel that my DTI's are not handling the gravity well and I am getting false readings.
Now the main question I have been looking for an answer to is if a coaxial indicator would give me a more consistent and accurate reading on the concentricity of this hole. I have read a few forums and everyone is a mess with their opinion on coaxial vs DTI when using them in the horizontal position. We are trying to get the most accurate holding for our reamers as they are profiled reamers and subject to much higher cutting forces, the more concentric everything is the better for us.
P.S. Please don't argue about having just bored the hole to size vs reaming it. Was not entirely my choice on the matter.
Anyways... I currently have used two different .0005" graduation dial indicators mounted into the chuck with a Interapid test indicator holder (the kind that uses links with screws to tighten in place), and I am sweeping in the ID hole on the mounted fixture block. I have seen about .0015" out of concentricity in the "Y" axis (If using zero reference on bottom of hole then top of hole is showing .003" off the zero). Now I have noticed that any of our DTI's that I use don't repeat the best, and when I used a longer stem indicator with .0001" graduation just for the heck of it, it was showing .002" out of concentricity. I feel that my DTI's are not handling the gravity well and I am getting false readings.
Now the main question I have been looking for an answer to is if a coaxial indicator would give me a more consistent and accurate reading on the concentricity of this hole. I have read a few forums and everyone is a mess with their opinion on coaxial vs DTI when using them in the horizontal position. We are trying to get the most accurate holding for our reamers as they are profiled reamers and subject to much higher cutting forces, the more concentric everything is the better for us.
P.S. Please don't argue about having just bored the hole to size vs reaming it. Was not entirely my choice on the matter.
