Cheap, easy and accurate Drill Press thickness calipers.
Posted: Fri Feb 01, 2008 8:17 pm
I got the genesis for this idea from the OLF I believe but could not find the original post to give credit where due or to copy from for that matter so I adapted to suit my own needs. This was one of those ideas that as soon as I first seen it, I thought brilliant! This will work, take bugger all to set up and, because LMI want around $192USD before shipping for their 12" calipers, can save me a lot of money 
In other words it had all of the criteria to qualify as a nooby lute in AU must do tool project.
All you realy need is a cheapo dial indicator from Ebay, a bit of scrap hardwood, a couple of bolts, nuts, and washers, some glue, chipboard screws and a plastic screw head dressing cap from bunnies. Oh, and let's not forget the drill press. If you don't have one of these, forget the LMI calipers, buy the drill press and make this jig you will be real happy with yourself if you do.
Anyhow, to start off with I made an auxiliary table for my drill press out of a sink cutout which I shimmed to be dead level and at 90 degree to the chuck. This table is used to get great results with a Wagner Finger Dicer and a sanding drum when shaping. The auxiliary table is in used so much that I made it easy to remove and replace. In the image below you can see it has locating dowels that ensure the table goes back on in the same place each time. It is also fitted with toggle clamps and can be snapped securely in place in just a few seconds.
I made the base of my thickness calipers to friction fit this auxiliary table so I can leave the table in place and just push the base of the calipers into position when required. That is realy the only reason the auxiliary table is so prominent in these images but I just thought I would take the time to explain the table anyhow as it has been an extremely useful addition in it's own right. At the end of the day however, as far as these calipers are concerned, a level surface is not a big issue, but a stable surface is a must.
Here is a picture of the calipers set up on the auxiliary table and ready for use.
And here they are in action
As you can see this is pretty straight forward to make. You just drill a hole through a scrap bit of hardwood and insert a bolt long enough to allow it to be fastened in the drill chuck. You drill another hole at the other end of the scrap and secure the dial gauge with a 1/4" bolt and a nut with a lock washer. Take your time here, the holes should be snug as you do not want ANY movement at all once this is nipped up.
Here is a couple of images showing the dial gauge fixture un-chucked from the drill.
Too easy
As I said above, I made the base section of my calipers so it would friction fit over my auxiliary table. That way I can slip it on an off in just a second. It is just a length of Jarrah with a block screwed to each end and it pushes into place and hold firm enough to not move about. Using the calipers is a light duty task so do not go overboard with this "friction fit" just snug is fine as too tight may cause it to bind and not sit quite flush to the surface of the table. Remember a stable surface is the point of using the drill-press in the first place so this needs to be right, no movement, but not too tight.
Before you put your end blocks in place on your base bar however, you first need to determine where to locate the underside reference button of the calipers. To do this, start with an over-sized base bar which will over hang your table or surface by around 70mm each end. Place a small block of hardwood with a hole drilled in the centre on to the top surface of your base bar around the centre point and glue and clamp it into place. When the glue has grabbed, drill and screw a chipboard screw with countersunk dressing cup into the small block and fit the dressing cap.
Here is an image of the small block with the dressing cap ready to be pushed into place. This is important as the soft plastic will avoid marring the spruce of your soundboard when using the calipers.
Snap the dressing cup into place on the screw and then chuck the dial indicator portion of the calipers into the drill. Swing the dial gauge to a position on the table were you will be most comfortable using it to check the thickness of your work. You do not need to worry too much about the drill head turning, the belt friction of the press should be enough to hold the dial indicator in place. Now, after adjusting the table of the drill-press to a height which will bring the two together and depress the pin of the dial indicator a little, move the base bar under the dial indicator pin so that the centre of the plastic dressing cap meets the end of the dial indicator pin.
Like so
Clamp the base bar into position and fit the end blocks one at a time with screw and glue remembering that friction fit. Here you can see a block at one end of the base bar snugly against the edge of the auxiliary table. Be careful not to allow the squeeze out from the end block to glue your base bar to the auxiliary table or I will laugh at you
Here is the the calipers shown from the side all ready to go.
As a bonus, you can leave the base bar off the table, wind the table up to meet the dial indicator, and rotate the chuck (by hand
) to check that your table is flat
Just a word of warning, don't be a dickhead and turn the freak'in drill on with your dial indicator chucked in place, it could get a little messy
Cheers all
Kim
In other words it had all of the criteria to qualify as a nooby lute in AU must do tool project.All you realy need is a cheapo dial indicator from Ebay, a bit of scrap hardwood, a couple of bolts, nuts, and washers, some glue, chipboard screws and a plastic screw head dressing cap from bunnies. Oh, and let's not forget the drill press. If you don't have one of these, forget the LMI calipers, buy the drill press and make this jig you will be real happy with yourself if you do.
Anyhow, to start off with I made an auxiliary table for my drill press out of a sink cutout which I shimmed to be dead level and at 90 degree to the chuck. This table is used to get great results with a Wagner Finger Dicer and a sanding drum when shaping. The auxiliary table is in used so much that I made it easy to remove and replace. In the image below you can see it has locating dowels that ensure the table goes back on in the same place each time. It is also fitted with toggle clamps and can be snapped securely in place in just a few seconds.
I made the base of my thickness calipers to friction fit this auxiliary table so I can leave the table in place and just push the base of the calipers into position when required. That is realy the only reason the auxiliary table is so prominent in these images but I just thought I would take the time to explain the table anyhow as it has been an extremely useful addition in it's own right. At the end of the day however, as far as these calipers are concerned, a level surface is not a big issue, but a stable surface is a must.
Here is a picture of the calipers set up on the auxiliary table and ready for use.
And here they are in action
As you can see this is pretty straight forward to make. You just drill a hole through a scrap bit of hardwood and insert a bolt long enough to allow it to be fastened in the drill chuck. You drill another hole at the other end of the scrap and secure the dial gauge with a 1/4" bolt and a nut with a lock washer. Take your time here, the holes should be snug as you do not want ANY movement at all once this is nipped up.
Here is a couple of images showing the dial gauge fixture un-chucked from the drill.
Too easy
As I said above, I made the base section of my calipers so it would friction fit over my auxiliary table. That way I can slip it on an off in just a second. It is just a length of Jarrah with a block screwed to each end and it pushes into place and hold firm enough to not move about. Using the calipers is a light duty task so do not go overboard with this "friction fit" just snug is fine as too tight may cause it to bind and not sit quite flush to the surface of the table. Remember a stable surface is the point of using the drill-press in the first place so this needs to be right, no movement, but not too tight.
Before you put your end blocks in place on your base bar however, you first need to determine where to locate the underside reference button of the calipers. To do this, start with an over-sized base bar which will over hang your table or surface by around 70mm each end. Place a small block of hardwood with a hole drilled in the centre on to the top surface of your base bar around the centre point and glue and clamp it into place. When the glue has grabbed, drill and screw a chipboard screw with countersunk dressing cup into the small block and fit the dressing cap.
Here is an image of the small block with the dressing cap ready to be pushed into place. This is important as the soft plastic will avoid marring the spruce of your soundboard when using the calipers.
Snap the dressing cup into place on the screw and then chuck the dial indicator portion of the calipers into the drill. Swing the dial gauge to a position on the table were you will be most comfortable using it to check the thickness of your work. You do not need to worry too much about the drill head turning, the belt friction of the press should be enough to hold the dial indicator in place. Now, after adjusting the table of the drill-press to a height which will bring the two together and depress the pin of the dial indicator a little, move the base bar under the dial indicator pin so that the centre of the plastic dressing cap meets the end of the dial indicator pin.
Like so
Clamp the base bar into position and fit the end blocks one at a time with screw and glue remembering that friction fit. Here you can see a block at one end of the base bar snugly against the edge of the auxiliary table. Be careful not to allow the squeeze out from the end block to glue your base bar to the auxiliary table or I will laugh at you
Here is the the calipers shown from the side all ready to go.
As a bonus, you can leave the base bar off the table, wind the table up to meet the dial indicator, and rotate the chuck (by hand
) to check that your table is flat Just a word of warning, don't be a dickhead and turn the freak'in drill on with your dial indicator chucked in place, it could get a little messy
Cheers all
Kim
