Dewalt (DWHT77100-XJ) laser measure - WAY off?

[reoreborn85]

Hi.

Sorry if this is a dopy question.
I purchased a Dewalt laser (DWHT77100-XJ measure from Toolstation 5 months ago and have only used it once (to try it) and it was purchased in a sale with plans to use it when carrying out replacing a roof of the conservatory which I am now doing. I took it out to try it yesterday and it seems WAY off. I have the laser set to take the measurement from the base of the unit (Not where the laser starts). The batteries are on three bars (full). I've cleaned the laser with a lint free cloth.
Here is an example.

A gap between the door and the shelving unit.
Tape measure: 500mm
Laser: 554mm (Second measurement was 560)

Door frame:

TM: 730mm exactly.
Laser: 738mm

Chimney alcove:
Laser:1.680m
TM: 1.674mm


I called tool station today to work out if i had to take it into the store or send it back to dewalt. The store is 10miles away so i wanted to make sure before taking it in. The person said "That sounds about accurate for a laser measure. Maybe you need to recalibrate it? We can't take it back for that"

Is this right?!?! I was always dubious about laser measures but i'd heard they were extremely accurate or if they were off it would be by half a millimetre per meter.

I've looked through the manual and can't see anything about recalibrating it.

Any advice?!?! Am i being fobbed off?

 

[jj4091]

From a google search
The DWHT77100-XJ Dewalt laser measure does not appear to have a user-accessible calibration function. If you suspect the laser is not accurate, it's recommended to contact Dewalt or an authorized service center to inquire about recalibration policies. Generally, if the measurements are off by 5mm or more at 10m, recalibration may be necessary according to EngineerSupply.

 

[freddiemercurystwin]

https://www.dewalt.co.uk/product/dwht77100-xj/dlm30-30m-distance-measurer Should be 3mm/1m that said I'd have little faith in anything costing so little.

 

[reoreborn85]

https://www.dewalt.co.uk/product/dwht77100-xj/dlm30-30m-distance-measurer Should be 3mm/1m that said I'd have little faith in anything costing so little.

It says per 10m.

Agreed but watching a few independent reviews on youtube say it's fine for DIY'ers. It doesn't have to be that accurate but 2-3cm's off is going a bit far.

 

[freddiemercurystwin]

Well the specs are irrelevant anyway just take it back, Toolstation are pretty good assuming you have a receipt.

 

[opps]

https://www.dewalt.co.uk/product/dwht77100-xj/dlm30-30m-distance-measurer Should be 3mm/1m that said I'd have little faith in anything costing so little.

If you google the model number, the description for the Dewalt page says "The unit is accurate to within 3 metres at 10 metres"

Looking at the source code, someone made a bit of a boo-boo.

 

[reoreborn85]

If you google the model number, the description for the Dewalt page says "The unit is accurate to within 3 metres at 10 metres"

Looking at the source code, someone made a bit of a boo-boo.

Lol thats a hell of a discrepancy!

 

[^woody^]

Laser measures are not really designed for short measurements.

But fundamentally, the target material will affect the measurement - colour, surface roughness, reflectivity etc.

Fir maximum accuracy, use a target plate designed for the type of laser beam

 

[^woody^]

Lol thats a hell of a discrepancy!

I've seen a few jobs where they have worked to that tolerance. Now I know why.

 

[reoreborn85]

Laser measures are not really designed for short measurements.

But fundamentally, the target material will affect the measurement - colour, surface roughness, reflectivity etc.

Fir maximum accuracy, use a target plate designed for the type of laser beam

Thank you.

It was accurate when we first purchased it though which is odd. Literally bang on the dot. We tried it for short distances and the length of the garden 10m. Bloody thing lol.
The surface was breeze block, Painted walls (matt) and one was tile.

Currently in contact with toolstation online support and waiting for a reply.

 

[JBR]

Having read all this, I think I'll give laser measurers a miss! I stick to tape measure and do it in bits.

 

[reoreborn85]

Having read all this, I think I'll give laser measurers a miss! I stick to tape measure and do it in bits.

No. Honestly they're really good. I just had a dodgy one. I managed to get them to agree to take it back. The new one is spot on again.

I think if you're planning on doing a lot of 'alcove' or internal measuring they're brilliant.

 

[lostinthelight]

I think if you're planning on doing a lot of 'alcove' or internal measuring they're brilliant.

For shorter dead accurate internal measuring you won't beat a Hultafors Talmeter tape measure

 

[freddiemercurystwin]

I'd never use one for anything that required mm accuracy. Fine for surveying etc. Even tape measures vary between brands.