Can anyone recommend a 2"-6" dial bore gauge make/model for the occasional engine builder? I've been looking at both .0001 and .0005 increment models and I'm not sure if the extra accuracy is needed. Seems like you can spend anywhere between $100 and $700 on one of these things.

Starrett is the "industry standard" for tools. Measuring to 0.0001 inch is a plus. The bigger the dial face, the more increments given. Make sure any tool comes with its own calibration standard, i.e., measuring block. Keep the block and tool for a day at room temp before checking.

IMO, I suggest Starrett only if one will use these tools for professional use. If one uses for at-home on your own stuff, alittle lesser quality would be doable. Probably, just used to check the shop's work. From my experience, do not buy the digital calipers, I find the wheel slips, plus it requires a battery. Mechanical dials are the way to go. Calipers having one 360* revolution for 0.1
inch are a goood choice. If you have one quality tool in your box, you can use it as a standard for the rest.

One can get tools calibrated at your local cal lab every year for a nominal fee. Look in the Yellow Pages under Test Equipment Calibration.

I'm sure others here will offer their advice, which is a good thing.

I am unfamilar with a Starrett dial bore guage so I can't comment on them except to say it's a very good company which makes excellent products.

The machine shop I use has a Sunnen dial bore guage. Very very nice piece of equiptment. Measures down to a tenth of a 1/1000 of an inch, and is built for daily usage. If you ever lay your hands on one of these, you'll be ruined for life.

Anyway, I'd like to hear about some other alternatives to.

The Starrett dial bores are very adequate to measure engine bores. When you set them up make sure that you set them as close to the mean of the number you want to have. The reason for this is a natural hysterisis when you measure far from your master (micrometer, gage blocks etc.)

Rock the gage to ensure you are properly on center of the bore and readings are repeating before you decide that you have the number.

When I set up a bore gage, I try to stay within +/-1/4 of gage dial reading for the actual working range. For example, if the gage dial, or gage travel is +/-.100 try to stay within +/-.025 from the gage natural 0 set point. Don't set a dial bore gage up at or near its dial travel limits.

Sunnen is the best I have used, Starrett is very good also. If you aren`t concerned how long it takes to take several readings a set of quality telescoping gauges along with a high quality set of mic`s will do just fine. I would recommend Starrett for both of these. You just need to get a feel how to use them and take several readings until you get consistant results. Using a bore gauge accurately will take some practice also. Brent

Sunnen is the best by far. Big $$ though. Watch ebay for dial bores. Stay with the name brands like starrett and mitutoyo. Standard also makes a good gage but the larger sizes are not usually available. A decent used 3"-6" bore gage set will can be had for around 100-300 used. If you stay with the name brands, repair parts are available as gage lens break and tips wear throwing your readings.

good prices here: http://www.use-enco.com/CGI/INSRHM
see if there is anything you like.
Check the specials as they often have them on sale. I'd wait for the one you want to be put on sale.
David

To horn in here as I usually do, He, He!!

David, did you get the name and address of the company that was selling the "hard-bits" that were being sold at SEMA 2003 on the area floor?

The ones that drilled through files, then ceramic tiles, then wood, then cold-rolled steel and just kept right on a drilling back to the files??

I would like to get a set of them.

pdq67

I would like to build a 383 and be able to check what comes back from the machine shop before and during assembly. Since I don't see myself ever doing machine work myself, is it necessary to buy name-brand measurement tools?

It seems to me that an off-brand tool that goes down to .0001" is better than using plasti-gauge.

I know that opinions on tool quality ranks right up there with religion but I think some of us lesser experienced enthusiasts NEED to know what is necessary and the trade-offs of taking a lower cost alternative.

Thanks

Imho, tool quality is in the eye of the beholder AS WELL AS the pocketbook!!

Sure the best is great and lasts forever if taken care of!! Especially if you are a Professional that uses them on a regular basis to make a living.

But for hobbiest's like most of us are, a good set of inexpensive tools is fine if we just realize their shortcomings and calibrate them accordingly. Yes, keep gage checkers handy that have been calibrated/checked by a trusted expensive good tool set and then periodically check the inexpensive tools with them!! And we should be fine, again imho..

I find that I have to measure something about three times just so I can remember the "feel" of how I should do the measuring b/c I flat don't do much of it anymore!!

If you want AND can afford the expensive stuff, by all means go for it AND think of it as tools to leave to your kids in your will!

But otherwise please consider buying the inexpensive stuff for occasional use if you are "billfold challanged" like I always seem to be.. Again, it's a personal value judgement sorta thing here, too.......

pdq67

As a 15 year machinist, I am going to give my preferences on measuring instruments based on the gages I have used. The basic measuring tools I use at home for building engine`s and cars are:

1: 0-6" caliper, this is invaluable. Once you have one, you won`t know what you ever did without it. I use it to quickly check a hole size, a bolt diameter, material thickness or diameter, drill size, hole depth, whether an engine block has been bored oversize, etc. I always bring one to swap meets to check used parts. Don`t, however, use a caliper to measure tolerances closer than +/- .002. They just aren`t accurate to these tolerances, regardless of what the manufacturer says. You can make one read totally different, depending on how much pressure you use.

For a mechanical dial caliper I recommend Brown and Sharpe brand with .001 increments. The gear rack is better protected to keep debris out of the teeth. One small metal chip will ruin a caliper. Starrett`s are good, but can be easily damaged this way.

For a digital caliper, I recommend Mitutoyo. They are the most durable digital caliper I have found. Just don`t get one wet.

2: Micrometers: Starrett and Mitutoyo are probably the best. I prefer the feel of Starrett`s and that`s what I own. Brown and Sharpe and Fowler are a couple of other good brands, just a step below the first two. You will have to choose between a friction or ratchet thimble. Everyone has their own preference. These four are what I would recommend to a professional.

For the hobbiest, a set of import`s will probably do just fine. A 0-6" set can be purchased for under $200. I would definately have the standards, which come with, checked by someone else with a quality mic set, just to make sure they are accurate.

3: Telescoping gages: These are used the same as a bore gage and are just as accurate when used properly. These expand to measure the inside diameter of a bore, you then measure the telescoping gage with an outside mic to get your reading. They are also fairly inexpensive, a 0-6" set ranges from $20 for imports to $130 for starrett`s. Something in the middle would be just fine for the hobbiest. One thing I like about using telescoping gages is that the same micrometer is used to check both the crankshaft and the main bore or connecting rod bore. Or the piston OD and bore ID. What we are acually after is the difference between the two, or the clearance. This takes out the variable of one of the two instrument`s being out of calibration, if using a micrometer and bore gauge instead.

4: Dial indicator and mag base. These are cheap and can be used to measure backlash when setting up rearend gears, runout on a transmission bellhousing, degreeing a camshaft, etc. No reason to spend alot on these, they all seem to work the same. Just be sure to get one with enough travel to check valve lift.

5: Bore gauges. I don`t have one at home, the telescoping gauges do just fine for me. The two I have used are: Sunnen and Starrett. The Sunnen is the best by far.


Using measuring instruments: When taking measurements, both the instrument and the part being measured should be the same temperature. Preferably around 70 degrees. A crankshaft or engine block should be in this environment for a day to get accurate readings. If you are checking bearing clearances, measure the block and the crank at the same time to eliminate variables.

Hopefully this helps, Brent

L-78,

Do you have any tricks to ensure the telescoping gauge is square in the bore when taking bore measurements? I tried to check mine this way last weekend and out of 10 readings, I couldn't duplicate a single one.

Chris, you should put the telescoping gage in the bore at a slight angle. Tighten the locking stem slightly. Slowly rock the telescoping gage past center. Remove from the bore and then fully tighten the locking stem and measure with the mic. Do this several times to be sure you are getting repeatable readings. Brent

Thanks, Brent. I'll give that a try. I see you are from Sioux Falls. I used to live there in '75-'76. I have a freind up there with a '67 thast looks a lot like yours. I live near Sioux City.

Hey Chris, I get down to Sioux City fairly often, lived there around 90-91. Had some work on my car done there also, Dan Harry at Harry`s Heads did the machinework and heads. Bob Oien at Professional Exhaust did the exhaust. I`m planning to go to Bob`s car show next spring, maybe we could get together there, or if you run at Thunder Valley let me know. Later, Brent

It's a small world Brent! I've known Bob since he bent pipes at Jamison Imports in the mid-seventies. In fact he's my friend's brother-in-law. If I make it to Bob's show, I'll be sure to look you up. I don't race at Thunder Valley. It's 110 mile drive from here. Scribner is only 93. I do have many fond memories of Thunder Valley from my High School days.

Take care!