Was back on the climax portable boring mill yesterday for the first time in a while .. and got to thinking about how ridiculous it is that i am still using spring calipers to measure my bores.. its the only thing i can find in any tooling catalog that can clear the 2.25 bar. I am often doing bushing bores with a .001" after lots of practice I have no problem doing that but it doesent take much a miss a thou with those things... has anyone else come accross somthing better?
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Portable line boring measurement
- Thread starter ryanbcnc
- Start date
- Replies 16
- Views 8,046
Look at Berco's catalogue. I know they have telescope gages that go in cutter holes. With Berco's stuff its easy to move the bar out of the hole. If your rig is difficult to pull the bar out of the hole without rotation they may not work as well.
I have seen bore gages with U shaped anvils to clear a bar, but you may not have enough room between the bar and bore for them. I have also seen plug gages made to clear the bar for roughing steps.
I have seen bore gages with U shaped anvils to clear a bar, but you may not have enough room between the bar and bore for them. I have also seen plug gages made to clear the bar for roughing steps.
Hbjj
Cast Iron
- Joined
- Mar 18, 2013
- Location
- Washington st
If I need a true. 001 fit I do a second op
Like ream or hone
On the junk I run measuring from the bar to the wall would be inaccurate owing to bar runout/deflection
YMMV
Like ream or hone
On the junk I run measuring from the bar to the wall would be inaccurate owing to bar runout/deflection
YMMV
slowmotion
Cast Iron
- Joined
- Mar 31, 2013
- Location
- Danville Virginia
I have a set of snap gages as described above that I use on my line bore. They came from RMC in Saginaw MI. Easy to use and the range is from approx 1.75"-4.50".
Forrest Addy
Diamond
- Joined
- Dec 20, 2000
- Location
- Bremerton WA USA
In my checkered career I've bored many a split case double suction pump on a HBM. Many of the people I'worked with were mastered of HBM line boring techniques. Lunchtime conversation often visited how to check bore sized with the bar in place. These were capable, inventive people and many novel solutions were explored and even prototyped. Some were elaborate monstrosities with flex joints and dial indicators unwieldy as opening an umbrella in a sleeping bag. It always came back to spring calipers often with legs bent and twisted in novel ways to make the reach. Starrett inside spring calipers with the round legs and clones seemed to be the most efficacious. #274 I think. Marshal Whitledge had quite a collection, dozens. I recall one pair whose legs were bent sideways an inch or more and extended radially to measure a step in a seal ring bore.
In a split cased pump you could always lift the cover, clamp a block to slightly lap the half-bore and make a short trial cut to prove tool setting, but continuous bores like through a bronze sleeve often had a long center sections where the center part was a mystery diameter until the bar was extracted. I recall a through hull fitting for a directional array where there were multiple steps in the bore that had to be carefully sequenced because clearance between bar and bore was so small you couldn't reach inner features with calipers once subsequent features were bored.
Some jobs require line boring. In-process measurement will be a hassle until some cleaver - make that VERY clever fellow comes up with a general purpose measuring apparatus to solve the low clearance in-extractable tooling to bore measurement problem.
In the meantime, it's calipers in some form and careful sensitive measurement and second party double checking. My particular contribution to solving the problem of consistent measurement is to never look at the mike until you are satisfied with the feel. You can "wish" on pr off a thousandth or more without realizing it. DAMHIKT
Some times the hard way is the only way. That's why they pay us the big money.
Yeah, I know. I'm no help. What can I say: I'm an old fart.
In a split cased pump you could always lift the cover, clamp a block to slightly lap the half-bore and make a short trial cut to prove tool setting, but continuous bores like through a bronze sleeve often had a long center sections where the center part was a mystery diameter until the bar was extracted. I recall a through hull fitting for a directional array where there were multiple steps in the bore that had to be carefully sequenced because clearance between bar and bore was so small you couldn't reach inner features with calipers once subsequent features were bored.
Some jobs require line boring. In-process measurement will be a hassle until some cleaver - make that VERY clever fellow comes up with a general purpose measuring apparatus to solve the low clearance in-extractable tooling to bore measurement problem.
In the meantime, it's calipers in some form and careful sensitive measurement and second party double checking. My particular contribution to solving the problem of consistent measurement is to never look at the mike until you are satisfied with the feel. You can "wish" on pr off a thousandth or more without realizing it. DAMHIKT
Some times the hard way is the only way. That's why they pay us the big money.
Yeah, I know. I'm no help. What can I say: I'm an old fart.
I get old beat too fuck OD mics at auctions and weld or braze tooling ball/rod + tooling ball Frankenstein type of things on them.
I do quite a bit of line boring on portabore's and in the shop on our HBMs.
To be honest I've never used spring calipers to measure my bores.
The large adjustable OD mics work best as you can make rods that go out instead of in, and then just have to come up with something to cover the thimble on the other side.
You can also make your own out of titanium, one of my guys did that for a particularly large set of bores, can't remember what alloy he used I had it waterjetted for him.
...edit: I should mention that most of the bores I do are large (20"+), so this may not work well for super small bores? Good luck.
I do quite a bit of line boring on portabore's and in the shop on our HBMs.
To be honest I've never used spring calipers to measure my bores.
The large adjustable OD mics work best as you can make rods that go out instead of in, and then just have to come up with something to cover the thimble on the other side.
You can also make your own out of titanium, one of my guys did that for a particularly large set of bores, can't remember what alloy he used I had it waterjetted for him.
...edit: I should mention that most of the bores I do are large (20"+), so this may not work well for super small bores? Good luck.
EPAIII
Diamond
- Joined
- Nov 23, 2003
- Location
- Beaumont, TX, USA
That replaces two sources for error (spring caliper and mike) with three (bar diameter, measurement, and multiplication which double the measurement error). Sorry, but IMHO you are better off with the spring caliper.
atex57
Stainless
- Joined
- Sep 6, 2006
- Location
- SW Wisconsin
I made some adapters to fit a caliper. Cut a slot near the end on the side of a piece of 1/2" CR round to fit over the jaw of the caliper, drill and tap the end for a setscrew to clamp it to the jaw, and braze a bearing ball to that side about 2" away. One for each jaw faced each way.
This way the caliper reaches around the bar and the adapters drop down the bore.
I like using a digital caliper, set a micrometer to finished bore size and zero the caliper to that size. That way the caliper reading is always the amount to be removed.
Climax makes good but pricey stuff.
Ed.
This way the caliper reaches around the bar and the adapters drop down the bore.
I like using a digital caliper, set a micrometer to finished bore size and zero the caliper to that size. That way the caliper reading is always the amount to be removed.
Climax makes good but pricey stuff.
Ed.
number 2
Hot Rolled
- Joined
- Aug 13, 2009
- Location
- Western Australia
I have seen half ring type measuring apparatus with a ball and screw like an inside mike on an outside frame but requires quite a bit of room to get in there. Have never used one. All home made out of pipe or whatever and a bolt. The cool part was using a nylon nut on the bolt to add stiffness and a lock to the screw. Quite clever. Dunno how well it works.
I usually use inside spring calipers also. My advice, work out what’s going on. When I did my first job using them I thought to myself I got to figure this out, I concluded the way in which you hold them, pressure if any applied to hold one end in position, and the way you mic up after removal all add inaccuracy. Sort that out and I think you will be fine. Just keep it all the same. I can usually get within half a thou between spring caliper and inside mic feel. For larger bores I measure near the halfway point with an inside mic to the bar, then the opposite side of the bore to the bar, then add the two plus bar diameter and that is usually pretty good. Just be careful how you measure it seems only a few atoms is needed between loose and tight feel during measuring and finding the bar high spot can be tedious.
I usually use inside spring calipers also. My advice, work out what’s going on. When I did my first job using them I thought to myself I got to figure this out, I concluded the way in which you hold them, pressure if any applied to hold one end in position, and the way you mic up after removal all add inaccuracy. Sort that out and I think you will be fine. Just keep it all the same. I can usually get within half a thou between spring caliper and inside mic feel. For larger bores I measure near the halfway point with an inside mic to the bar, then the opposite side of the bore to the bar, then add the two plus bar diameter and that is usually pretty good. Just be careful how you measure it seems only a few atoms is needed between loose and tight feel during measuring and finding the bar high spot can be tedious.
I was helping a local portable welder
operate his portable line bore, and had a set
of caliper "clip ons's" like described above made
for him.
Another thing I proposed, was a adapter plate used in between the 4 bolt flange
bearings, and the plate you weld onto
the part being bored.
By making up some adapters with accurate
dowel pins, you can align the bar & bearings,
weld your plates in place, and start boring.
When you need to get the last couple of
close tolerance measurements, you could
unbolt the bearings, and pull the bar.
With the accurate dowelled plates still in
place, your bearings & bar go right
back in place with no alignment hassles.
operate his portable line bore, and had a set
of caliper "clip ons's" like described above made
for him.
Another thing I proposed, was a adapter plate used in between the 4 bolt flange
bearings, and the plate you weld onto
the part being bored.
By making up some adapters with accurate
dowel pins, you can align the bar & bearings,
weld your plates in place, and start boring.
When you need to get the last couple of
close tolerance measurements, you could
unbolt the bearings, and pull the bar.
With the accurate dowelled plates still in
place, your bearings & bar go right
back in place with no alignment hassles.
I agree but the OP does not have confidence in the caliper. What ever he uses he will do better with a method he is confident of. I also agree with Hbjj. Most portable/field equipment leaves a less than perfect finish. A finish hone op gives a much better finish and cylindricity.
James H Clark
Stainless
- Joined
- May 11, 2011
- Location
- southern in.
Ryan: I once had a line boring job that was similar to what you describe. I made a frame from the center of an old Ford brake drum. The center hole in the drum would clear the bar with some room and I drilled and tapped fine thread holes 180 degrees apart. Each screw was ball shaped and the one end was Loc-tited and the other was snug but movable. It looked like crap, but worked pretty good. I used one of the lug bolt holes to install a handle. The cast iron of the brake drum was stiff enough to be reliable. I used spring calipers up to the last little bit, then used my little "inside mike" for the final cuts. Good luck.
JH
JH
eKretz
Diamond; Mod Squad
- Joined
- Mar 27, 2005
- Location
- Northwest Indiana, USA
I made a setup for this back in the day when I was doing a lot of line boring for the bores that needed to be right on. Basically a little attachment that clamped a test indicator onto a modified spring caliper leg. Used it sort of like a bore gage by sweeping and pivoting to find the smallest point and setting the indicator to zero there, then checking size with a micrometer set to bring the indicator back to the zero.
Lanza
Aluminum
- Joined
- Jun 22, 2007
- Location
- Western Australia
Just can across this. I know who made that tool, and we used it on line boring track pads of Lieberr type machines. It was a little light duty and could get 0.02 off if you were a heavy measurer. I seen one there where you could screw an inside mic (50-63 mitutoyo piece) into a home made c frame.
number 2
Hot Rolled
- Joined
- Aug 13, 2009
- Location
- Western Australia
The other week I cobbled together an L shaped rod 10mm in diameter, fit a wobbler ball and shaft on the horizontal part of the L sticking out, so you could put a finger dial on the vertical part of the L and compare the ID of the bore to a micrometer or other known bore. Worked ok but bit fiddly to find high/ low spot depending on axial or radial direction.
Spring calipers require you to stop and be very careful with feel, but they work just as well. Just wish they had a finer screw on the adjustment.
