LR32 Issue

[bruegf]

I've used my LR32 a number of times to drill shelf support pin holes, but this is the first time I've used it for 32mm system hinges.  I noticed after drilling the holes that even though the edge stops are set for 37mm, the holes ended up at 37.5mm in from the front edge.  My first thought was that bars had slipped since I first calibrated the stops, but I rechecked the calibration with the stops set at 0 and they slid freely in and out of the reference notch in the router base plate for the lr32 track.

Any idea why I'm seeing 37.5mm offset instead of 37mm?

Thanks

Fred

 

[ajones]

If you are using the of1010 I would think the router is not centered on the router mounting plate is the only other variable

 

[Brice Burrell]

If you are using the of1010 I would think the router is not centered on the router mounting plate is the only other variable

The first thing that comes to mind is that the bit wasn't perfectly centered.  Being off half a mm is nothing so it's not really a problem.

 

[Sparktrician]

Be sure that your rail is securely clamped down before you start boring.  They do have a tendency to wander if not clamped down. 

[smile]

 

[bruegf]

My router is a 1400 and I had just centered the router on the base plate using the supplied mandrel.  I can check to see if the mandrel is still centered, but I'm guessing it will be.

I'll also check the bit since I haven't removed it yet.  I didn't feel any vibration and I'd guess that being off that much would cause enough vibration to notice, but maybe not.

I didn't use clamps (but probably should have), but because all 4 side panels are off exactly the same 0.5mm, I'm skeptical that the unexpected 0.5mm offset is due to the rail slipping, but definitely something I'll need to remember to do next time.

Unfortunately for me, I forgot and drilled my hinge mount holes before applying the edging to the plywood, so the holes will end up being off by 1.5 mm instead of 0.5, I'm hoping the blum hinges I plan to use will enough adjustment that it won't be a problem.

Thanks for all the suggestions

Fred

 

[JeromeM]

I've used my LR32 a number of times to drill shelf support pin holes, but this is the first time I've used it for 32mm system hinges.  I noticed after drilling the holes that even though the edge stops are set for 37mm, the holes ended up at 37.5mm in from the front edge.  My first thought was that bars had slipped since I first calibrated the stops, but I rechecked the calibration with the stops set at 0 and they slid freely in and out of the reference notch in the router base plate for the lr32 track.

Any idea why I'm seeing 37.5mm offset instead of 37mm?

Thanks

Fred

The edge stops themselves may need calibrating. I don't have mine where I can get at them now but as I remember there is a procedure for adjusting them.

 

[bruegf]

Jerome,

Yes, I did the procedure again, thinking that must be what the problem is, but they were spot on.

Fred

 

[BMH]

The other variable is the tape measure and graduation bars are off by 0.5 mm. Easy fix, set up your stop at 36.5 on the bars.

 

[harry_]

bruegf,

Are you taking the measures using a tape?

If so, are you taking the measurements "mid-tape" or are you using the hook?

Is it possible that on one measurement you are pushing (butting) the tape and on the other you are pulling (hooking)?

Thus a "push" measure will always read accurately to another "push", as would a "pull" to another "pull".
However the hook would only need to be bent by .25mm to create a .5mm "error" and it would take little effort to bend a tape hook by that much.

 

[tbellemare]

Tape hooks are designed to slide the thickness of the hook end to account for inside/outside measurements. Some aren't so accurate...

Tom

 

[bruegf]

I was doing the measurements with my expensive and hopefully accurate woodpecker woodworking hook rule, but also got the same measurements with my Incra 12" T-Rule. 

Fred

 

[harry_]

Tape hooks are designed to slide the thickness of the hook end to account for inside/outside measurements. Some aren't so accurate...

Tom

Tom, that is correct but it doesn't account for hook itself getting bent. All you have to do is drop your tape and have it land on the hook and the amount of "error" we are talking about here show up.

Bruegf, That is all well and good and the likelihood of both tapes being off by the same amount is unlikely, but yet still possible. Additionally, in reference to Tom's post, is the tape "rated" to be accurate to .25mm on the hook's slide? You are talking about an error here that is ~1/64 of an inch. I am still inclined to "calibrate" the tape to its "mid-span", again it only has to be off by 1/2 of the error shown or about ~1/128 of an inch.

It is for this reason that whenever I set out to do crown moulding I check the hook against the tape before I even begin, as I can take the measurement utilizing the hook but usually cannot hook the crown when laying out the measure.

Lastly, this might not be the issue at all. At the same time I has seen so many overlook this, myself included.

 

[tbellemare]

The bent hook can certainly be an issue, Harry...

Another issue with tapes is that sometimes the metal tape itself gets plastically deformed from being stepped on or even coming back into the body. Those little deformations can add up to inaccuracies.

I ruined a Stabila BM 40, 33-footer, the other day by letting it fly back in from about 25'. It wrapped up on itself, got caught in the belt hook and ripped the metal tape. They have stout tapes also. If it hadn't ripped, it would almost certainly have some small kink that is not readily noticeable.

Tom

 

[tiralie]

Any idea why I'm seeing 37.5mm offset instead of 37mm?

Probably tightening the jaw guides so they are snug (or worn) draws the glide plate away from the edge by about .5 of a mm which is not a lot. The jaw guides are on the outside and when tightened pulls the glide plate (slightly) away from the edge you are measuring from.
Tim

 

[Sparktrician]

I've used my LR32 a number of times to drill shelf support pin holes, but this is the first time I've used it for 32mm system hinges.  I noticed after drilling the holes that even though the edge stops are set for 37mm, the holes ended up at 37.5mm in from the front edge.  My first thought was that bars had slipped since I first calibrated the stops, but I rechecked the calibration with the stops set at 0 and they slid freely in and out of the reference notch in the router base plate for the lr32 track.

Any idea why I'm seeing 37.5mm offset instead of 37mm?

Thanks

Fred

Just out of curiosity, Fred, why does 0.5mm really matter if all you're doing is supporting a shelf?  I understand the question in the context of accuracy of setup, but does that "silly half-millimeter" really matter in the big scheme of things? 

 

[builderbob]

I think if I'm understanding the OP correctly, he was first using the LR-32 for the hinge drilling first. Still not that .5mm would make or break if the hinge is adjustable. I think he's more curious as to why in general is the setting off? Say you're line boring for slides and are set back or too far out on an inset cabinet, that could make a huge difference without spending extra time to rectify with spacers, etc. just a thought!

Bob

 

[bruegf]

Exactly right builderbob, I'm just trying to figure out if I've messed up somewhere or my stops are just off 0.5 mm. 

Here's what I've checked since first posting:

1) the mandrel is still centers properly so the router is properly center on the base plate.
2) I don't have any play between the base plate and the rail so the base plate is adjusted to the rail properly.
3) I've measured from the front edge to the outside edge of the 5mm hole with my dial calipers and verfied that the center of the hole is at 37.5mm instead of 35, i.e.  the o.d. of the 5mm hole is at 35 and 40mm instead of 34.5mm and 39.5 mm.
4) The calibration slot in the base plate is properly registed with the edge stops when the edge stop is set at 0mm.
5) The hole measures just under 5mm (ie 4.97mm) so I don't think the bit is slightly off center as I think the hole would end up over 5mm if it wasn't centered accurately.
6) My (relatively inexpensive) electronic dial calipers measure within .001" of my expensive Mitutoyo dial calipers, so its not inaccuracy in the measrement from the front edge to the hole.

So that leaves me with one of 3 reasons based on the discussion so far:

1) Because I didn't clamp the rail I somehow managed to get 4 panels off exactly the same 0.5 mm
2) The gibs on the base plate are worn and that pulled it over, although I've only used the LR32 for shelf pin holes in 5 cabinets before this, so wear should be non-existant, plus I sprayed the rail and base plate with a dry lubricant before I ever used it to (hopefully) minimize wear over time.
3) The LR32 stops are not accurate.

Anything anyone else can think of?

Thanks

Fred

 

[harry_]

bruegf,

Can I get you try 1 more thing?

do your set up the same as you always would. Presumably 'pulling' against the pins of the LR32 edge stops.
place something against the pins (straight edge, level, whatever) and push the assembly against that. clamp it & bore a couple of holes, measure for comparison.

Maybe, what you might want to do it re-calibrate them to the base plate again, however this time apply lateral tension in the same direction as you would have doing your layout. I am thinking this will fix the issue.

I just pulled my edge stops out and checked them. They have some "slop" to them and I can assure you that it is not from over use.

 

[bruegf]

Never thought about any give to the pins.  I'll give that a try and see what happens.

Thanks

Fred

 

[Brice Burrell]

Fred, I can't help be feel you are way over thinking this.  Forget the half millimeter, it's just not important enough to bother trying to figure out.  If you're really fixated on a solution, correct the error when you set the stops.  It's super easy to set the stops to a half millimeter.