Digital calipers 4"

[deverett]

I have a pair of Mitutoyo 6" digital calipers and they are silky smooth in operation. 6" is too long if I want to measure something in the milling machine, so I recently bought a set of 4" digital calipers for that purpose. Man, are they rough but for £7 including postage, I didn't expect luxury.

They have just received a bit of 'fettling' to try and improve the movement. Adjusting the gib screws didn't make any difference.

I took the mechanical bits apart and first of all cleaned out all the dust from the inside.
The top and bottom of the beam had very noticeable machining marks, so with a bit of fine emery cloth these were polished out, making sure to keep the beam square.
The bronze spring had quite sharp ends and was also sharply bent, not just from the middle, but also at one end (the end with the hole in) which no doubt contributed to the rough movement. The underside was rubbed on some fine emery so that the ends wouldn't plough a furrow in the beam. The central bend was then much reduced till it was almost straight.

After assembly and adjusting the gib screws, I was quite pleased with the results of my 1/2 hour's labour. The 'instrument' is a lot smoother, I wouldn't say silky smooth, but definitely a great improvement.

Dave
The Emerald Isle

 

[idahoan]

Maybe like Starrett, Mitutoyo is now having some of their tools made in China.

Dave

 

[deverett]

Dave

I have re-read my post and it wasn't clear, but my new 4" calipers are not Mitutoyo, but the usual cheapo unbranded Chinese ones. Hence the cheapo price!

Dave
The Emerald Isle

 

[Blogwitch]

I have to fully agree with you on this treatment Dave, it can make a surprising difference.

I got my technique sorted when I fitted these scales to a milling machine, every week I had to strip at least one down to get it working again.

I have just bought a 12" version, £21, for a specific job. I wouldn't say invested in one as if they last over a year, you are making on the deal. This one is rather sharp edged along the scale, so a little bit of smoothing off is required before it is put into use.

John