JPT-310 digital thickness gauge

[PaulO]

Has anyone fitted one of these to their Jet planer thickenesser?

I received one today from Axminster, well I had to get my 10% off something. It doesn't fit as the locating lug seems to be in the wrong place by about 7mm. Oh, and the Jet sticker is upside down. Maybe it was a friday gauge. Have contacted Axminster, but I don't expect them to get back to me until next week.

 

[pinkyinboro]

i am wanting one of them let me know if you sort it
cheers
chris

 

[wizer]

I thought I'd have bought one of them, but I've never felt the need for one yet.

 

[Derek Willis.]

Why do yopu need it?
Surely your P/T has a guage that you can work to!!
Just another gadget that can go wrong and just mucks up everything else!!!
I suppose I must be envious of being able to spend cash on useless extras.
Derek.

 

[PaulO]

Why do yopu need it?

Don't "need" it. The standard gauge requires you to bend down to avoid parallax errors, this gauge won't suffer from that so should make setting the height easier.

I don't think it is particularly likely to go wrong, this type of gauge is pretty common / proven. If it does, it is a twenty second change to revert to the previous system.

 

[wizer]

I just measure the wood itself rather than the going by the gauge, I don't think I've ever really used the gauge other than to get it in the general area.

 

[Derek Willis.]

Wizer, you got it that's the only way you are going to get what you want, ignore all the gadgets, the proper way is the right way.
Derek.

 

[pryally]

i had the same problem on my 260, called Jet (Brimarc) and they sent me instructions - you need to take the cover of, etc....

i have the e-mail at work if you need it, will be monday though

i've not bothered yet............

 

[RichardC]

Paul

If I recall correctly, you can adjust the position of the lug by loosening a nut on the inside of the cabinet. You have to take off the back panel, adjust the nut and position of the lug, locate the microadjuster onto the lug, tighten the nut and it should fit. Then pass a piece of timber through the thicknesser and match the thickness of the planed timber to the microadjuster's scale. I think that's what I did!!

Richard

 

[PaulO]

I just measure the wood itself rather than the going by the gauge, I don't think I've ever really used the gauge other than to get it in the general area.

Don't agree, even with the previous setup I can get it consistent to 0.05mm. Sure I check using calipers, but it is always consistent, if you don't trust your p/t gauge, then I suggest you get a decent p/t or adjust it :wink:

Axminster got back to me this afternoon and said that if I got my P/T more than a year ago I would have to drill a new hole, which I have done and it works fine, all setup and giving me 0.05mm accuracy without having to bend over to avoid parallax.

 

[wizer]

Maybe I am missing how they work. But if the digital gauge is not measuring the actual wood, then how can you rely on it being absolutely accurate?

I guess it depends on your fussiness or tolerances.

I have the JPT-260 BTW

 

[ivan]

I have one on my Jet 310. Why should anyone want one? well, when set up you can easily thickness to 0.1mm. That's as measured by vernier caliper, (the scale itself reads I think! in divisions of 0.02mm) and with no bending down peering at the parallax ridden pointer either! The pointer does tell me if I've wound down enough to change over P to T without my glasses, though...

Accuracy depends on machining of screw, and careful setting up. Always raise bed into position and lock. With the old scale I had difficulty determining which mm I was working at....

To fit, take off the inspection panel at the back, so you can get to the awkward setscrew Richard mentions (see manual p12 part No. 299). Remove thickneser wheel handle and the old scale, slip on the digital jobbie and wiggle it into place, tighten up the screw 299 carefully (plastic parts). Thickness something, measure with vernier caliper, and then rotate digital scale's bush till reading corresponds and thin tighten up with allen key.

Don't be surprised if the reading is out after you've changed the knives...

 

[PaulO]

Maybe I am missing how they work. But if the digital gauge is not measuring the actual wood, then how can you rely on it being absolutely accurate?

I guess it depends on your fussiness or tolerances.

I have the JPT-260 BTW

No need to make a fuss about the accuracy of the digital gauge, it is no more or less accurate than the original dial system, the only reason for installing it is to avoid the need to bend over to overcome parallax.

The accuracy of either system depends on the accuracy of:
:the rise and fall leadscrew
arallelism of the blades in the block
:Block to bed parallelism

All this gauge does is measure turns of the handle. One turn of the handle represents 4mm of bed rise, and as long as you measure on the rise to avoid backlash issues, it is repeatable to sub thou accuracy. It is measuring the position of the table. So once you have set it for a given knife setting (which is easy to do), you get repeatability within the tolerance of knife wear. The difference between a blunt set of knives and a sharp set is much less than a thou or two, so achieving consistency to within less than 0.1mm is easy.

So as I stated above, you can easily thickness to 0.05mm accuracy.

Tom, where do you think there is inaccuracy in the method? After all, measuring the position of the tool / workpiece is the method that all lathes, milling machines, shapers etc. have used for years to yield accurate results.

I final thickness all my stock to 0.1mm over final dimension, then finish off with three or four sets of shavings with a hand plane.