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Telescopic bore gauges

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Robin Graham17/04/2019 00:36:22
691 forum posts
161 photos

I am thinking to buy a set of telescopic bore gauges and have looked at the Arc Euro offering . Does anyone have experience of these particular tools? I had a look on Amazon for reviews of sets at around the same price (£17 ish for a set of six) and opinions were mixed. For example, one reviewer said of the Draper set that it was difficult to get repeatable measurements, but they were OK if one was aiming for 5 thou accuracy. I can do quite a bit better than that with old-fashioned calipers (the type where you rock them in the bore and aim for the same 'feel' in the mic), so no point in spending money if that's true. Of course I know that review isn't directly applicable to the Arc product and that it's not unknown for Amazon reviewers to be somewhat - erm - challenged*.

I'd go up to fifty quid maybe if it makes a significant difference, but Mitutoyo-type prices are too rich for me.

Any advice?


* Bought a mandolin off Amazon, (food slicing, not musical), reviewer said blades very sharp, but one star because fingers sliced when trying to shave the last bit off a carrot or summat. Manufacturer's fault apparently.


Postscript - One the daftest I've seen was on the Screwfix site - a chap bought some solid brass slot head screws and complained that (a) they didn't have pozidrive  heads, and (b) they were prone to shear. Don't buy!


Edited By Robin Graham on 17/04/2019 00:51:19

Bandersnatch17/04/2019 01:01:00
1586 forum posts
53 photos

Might be better if you change the link to one that goes to Arc ..... rather than Ikeasmiley

Robin Graham17/04/2019 01:14:51
691 forum posts
161 photos

Oops. Arc Euro telescopic gauges.



John Olsen17/04/2019 01:32:52
1028 forum posts
86 photos
1 articles

Mine didn't come from Arc Euro, but are the same sort of thing. They can be a bit fiddly, there is a bit of a knack to it but I would expect to get a bore within about a thou of nominal with them. But then the internal mike I have for larger bores also can be a bit fiddly, and they are a lot more expensive.


Paul Lousick17/04/2019 02:28:36
1369 forum posts
531 photos

I originally bought a set of the cheaper telescopic gauges but was not happy with them. Instead purchase a dial indicator type. £50 ish and includes a dial indicator. Easier to use for an unskilled operator like myself.


John Reese17/04/2019 03:03:06
834 forum posts

Save your money until you can afford a quality set of telescoping gauges. You will not be satisfied with the cheap ones. I don't recommend dial bore gauges unless you are measuring a lot of parts with the same diameter. It is a finnicky job setting one with a mike. Ideally they are set with a ring gauge but it is impractical to hafe ring gauges for every size you need to measure.

Hopper17/04/2019 03:41:20
4381 forum posts
92 photos

Depends what size you want to measure too. For half-inch and under, ball gauges work better.

John Haine17/04/2019 07:24:10
3006 forum posts
160 photos

I have one Starret that goes up to about one inch, and a set of Mitutoyo going from about 6 up to 50 (?) mm. The Starret came from a used tool stall on my local market, probably a quid or so, the other set came from a surplus tool stall at an MEX in a very tatty plastic wallet for probably about 15 quid a while back. I find them very useful and pretty accurate one you get the knack. Moral, look for used ones or a set of good quality.

David George 117/04/2019 07:26:59
1189 forum posts
405 photos

Hi Robin I have had a set of Mitotoyo gauges and I can get to less than a thou accuracy with mine but if I need to get to that accuracy I would use my internal micrometer. There is a knack to using them, put them in over size tighten, twist through 90 degrees along the bore and extract and measure with a micrometer carfuly. If in doubt measure again.


Martin Connelly17/04/2019 08:20:34
1216 forum posts
147 photos

I agree with the two earlier posts regarding dial bore gauges. Yes they are fiddly to set up and to some extent use, it is also possible to misread them. They do however give repeatable results that do not rely on good feel. Cheap telescoping gauges can feel like they need stripping and polishing inside to improve them.

If you need to bore pockets for bearings the dial type may be a good choice for you. As also stated above it depends on a lot of factors to make the decision of what is best for your current needs. When a lot of similar sized holes are required a three point micrometer bore gauge with checking and setting ring may be useful but this tends to be for industrial quantities.

Martin C

Neil Lickfold17/04/2019 08:20:51
590 forum posts
102 photos

Tele gauges are not like they used to be made for sure. Some need the slot in the expanding side to be cleaned up and polished smooth or stoned smooth. Same with the pin end and a little radius on the outer edge of the pinch pin. Then the cheap ones will work as well as an expensive set. Tele gauges do take some getting used to being able to get good repeatable results. Just get a ball bearing and measure them, and keep practicing until you get the size as the bearing. You should be able to get consistently better than 0.01mm of the actual size.

Emgee17/04/2019 08:34:20
1444 forum posts
212 photos

dormer drill blanks 6.0 to 10.0 x .10mm.jpgHello Robin

David has described the best way to use telescopic bore gauges, I have a set of Mitutoyo which were bought second hand many moons ago, I find they give better accuracy than earlier posts, but then I have been using them for many years. I usually measure over the gauge with a digital vernier.
Another advantage of the tel gauge is it will indicate if the bore is bell mouthed by the different dimensions over the gauge.

Several methods of measuring bores in my photo album, drill blanks above are simple to use as gauging the hole if you don't need the precise dimension.

Emgeetelescopic gauges.jpg

Clive Foster17/04/2019 09:27:15
2144 forum posts
73 photos

Agreed. No substitute for quality.

I have the same full M&W set in a box as Emgee plus the smaller half set and a few odd ones from good makes, M&W, Starrett, B&S. Which all work very well indeed. With care better than half a thou. Repeatably. Makes boring holes for light running or light push fits almost easy. So much so that I've never bothered to sort out a gauge mount adapter to get the Baty dial gauge on a stick device I was given years ago. All good but stick and gauge don't match.

(When someone offers me tooling "Was gonna throw it out but thought you might be able to use it." I always say "Oh Yes please!" first and think later.)

Got a cheapie import set way back, blue wallet maybe Draper, when that was all I could afford. Which, as has been said, frankly doesn't really work well enough. Within two thou is about the best that can be done repeatably. Kept as a loan tool, its been gone about 5 years now but I know where it is should it ever be needed.

Those things have to work really smoothly to be accurate. I'd be unsurprised to discover that an older one, nicely run in after a decade or three of use is actually better than it was when new.


Edited By Clive Foster on 17/04/2019 09:27:36

not done it yet17/04/2019 09:56:27
4482 forum posts
16 photos


What do you refer to as a ‘digital vernier’? Is it an analogue digital instrument?smiley

Rik Shaw17/04/2019 10:07:45
1313 forum posts
352 photos

I have a set. I do not find them "fiddly". I use them on a regular basis. Very good value for money. +1 for David George technique - I do the same.


Mike Poole17/04/2019 10:49:38
2538 forum posts
60 photos

I would recommend trying in the bore after measuring to be sure the gauge is still set to the size you wish to measure just in case anything moved during extraction or measuring.


mechman4817/04/2019 11:01:56
2626 forum posts
407 photos
Posted by Rik Shaw on 17/04/2019 10:07:45:

I have a set. I do not find them "fiddly". I use them on a regular basis. Very good value for money. +1 for David George technique - I do the same.


Use the same technique myself, not had any probs with gauging bores.


John Hinkley17/04/2019 11:06:33
845 forum posts
286 photos

I bought a cheap set off eBay a few years ago because I didn't know any better. It never occurred to me that they wouldn't be "accurate". I just got on with using them. For the accuracy that I aspire to, they are perfectly satisfactory. If you are only laying out £20 or so, buy them and see how you get on, I say.


JasonB17/04/2019 11:43:54
17826 forum posts
1949 photos
1 articles

I've had my own set from ARC for quite a while maybe 6-7yrs and they work OK for me. Do't get used that much but usually get dragged out when I'm doing the bore of an IC or steam engine where I find them useful to compare the feel along the length of the bore which on the open crank engines can often be 100-150mm long to see if there is any taper . All the engines seem to make good compression so the pistons and rings must fit OK.

I also have a second set from ARC that were part of the tooling supplied for the Milling series and they have a nicer feel than my own with the two sprung plungers moving more freely than my personal set and the finish is a bit better all round so looks like what Ketan has to offer at the moment will do form the average model engineer.

fishy-steve17/04/2019 12:53:03
122 forum posts
30 photos

I've got a cheap set in a blue wallet.(not from ARC). For me they are only any use for picking your nose with.

I have now purchased a set of second hand Starrett 229s.(The same as the set I use at work.)

A point that is worth making is that the Starrett 229s have 1 fixed bar and one sliding. In my experience it is far easier to get the correct feel with this type of telescopic gauge. The cheap sets tend to have 2 sliding bars. Also, I believe Starrett make a set with 2 sliding bars. Maybe someone could confirm this?


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