Shars Boring Head v. Criterion
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- Опубліковано 1 жов 2024
- Here's a side by side comparison between a 2" Shars boring head and a 2" Criterion boring head. I get into some of the things you need to do to set up and adjust a boring head and take multiple passes of different depths. Full disclosure, Shars did send me this boring head for review purposes. Shars.com part number is 202-8024.
Link to the Telescoping Gage video:
• How to Use Telescoping...
Hi thank you for the video. My name is Randy Melton, I worked at Criterion Machine Works for 30 years. I started there as a machinist in 1972 and left in 2002. The last 12 years I was the Production Manager or Chief of manufacturing Operations. I have kept in touch with some fellow workers and unfortunately I heard that Criterion was sold somewhere around 2012 ? You did an excellent job instructing how the boring head works. While working there I made a DBL 202 boring head out of plastic so that people could see the inner workings of the head. I still have it. In 1985 we had our 50th anniversary and both the 202 and 203 had 24 carat gold plated bar holders. We purchased other manufactures boring heads to see how they were. We found that some bar holders were not heat trreated and other things that could have caused problems. That particular boring head that you have looks loke an older version. The dial screws that we made were all ground between centers after heat treat and mat chrome , I ground a lot of dial screws on an Excello thread grinder back in the day. Okay time to sign off, keep on doing your good work. PS: Henry Brent started Criterion in 1935 and he named his boat the "Blue Chip"
That is awesome, Randy! It's great to get that kind of insight into a company's history from someone who lived it. Thank you so much for sharing.
Stuart - Nicely done as usual. I like and dislike the Shars Boring Head for the following reasons . The Boring Bars
have a nice flat that insures the Tool Bit is located on center . The two piece threaded body makes me goosey .
If I purchased one , I would lock the two body pieces togeather tightly . Then I would drill and pin them
togeather . Now the Boring Head becomes safe and Bi-directional . -- Jim
I been impressed with some of the shard tools. I’ve been running their nmtb40 and BT30 tool holders and collet chucks for a few years. With good collets they run as tru as an Lyndex holders that cost 5 times more.
I always like these import vs brandname comparisons. As a home gamer it helps my decision making. Great videos, thank you.
I enjoyed this. You didn't repeat yourself 99 times, concise, clear, well presented. Subscribed, and keep up the good work.
Glad you liked it. Thanks for watching!
Finally someone who's actually read the Criterion instructions about only needing to use the center screw to properly lock the head after an adjustment. I've noticed Criterion have now made an addition to there new heads and that center screw is now marked "lock". I've seen some on the forums insisting that all three screws need to be used to lock the slide more than a few times. A very good video and the only thing missing imo is it would have been nice to see both heads disassembled and compared side by side for the surface finish quality of the internals which does have an effect on how well the slide will make very small movements. I like my Criterion boring heads, but think there threaded connection between the shanks and heads would be vastly improved by changing it and using the much better Narex method. That way they can be rotated in either direction without the problem of the head unscrewing.
We bought a new Criterion head at work about six months ago and they've actually started filling in the outer holes with resin, so you're really going to have to work at it if you want to tighten all the screws.
would like to see you bore a hole then ream it then bore out only half of it with your boring head and do this with the dro zeroed and see if the hole is off center after boring.?? would indicate the insert is not center or the hole in the boring head is not center . would make a good follow up video . :)
I realize that this video is 6 years old, but I caught something at the end that I wanted to note. The import heads are designed to expand the opposite direction, i.e., the dial comes out, not in. That means that the dial screw is backed out in order to count up on the radius/diameter measurement.
Overall, good video with lots of good information!
Great insight on the gib screws! I learned something today that will stay with me the rest of my life! Thank you very much.
It’s interesting. This really does show that it’s the small things. These Chinese knockoffs are just “no thought” copies being made by people who aren’t tool makers, just somebody that has the requisite equipment to copy some drawings. That lack of care comes through in things like the dial. That being said, i do like Shars’ stuff in general. They tend to be more consistent in what you can expect from quality, fit and finish, and the price is always decent. I have a lot of shars stuff and use it often.
Absolutely one of the best videos I've seen on boring heads, you never mentioned the price difference between the two. 👍👍👍👍
It is pretty significant. The Shars set with bars and the shank is $188.95 currently. The Criterion head alone, no shank, no bars is $510.20 and another $100 or so for the shank. You can find them used of course and that's how I bought mine.
Thanks so much and already did Stuart, wondered if they ever changed the scale, that would mess me up. @@StuartdeHaro
@@douglasbattjes3991 I'm not sure if they did or not. They said they were going to.
Stuart, did or could you cover or explain how to set the cutter in the head, should it be 90 deg. to the radius, monkeyed around with my head and get some chattering when cutting. maybe it's the carbide cutters and not the inserts ones. Like to know just where it should set .?
@@douglasbattjes3991 I haven't covered that, but I certainly can. You would want it as close to center as you can make it, but you also need to make sure you have clearance on the cutter or it will just rub. I take it you're using the brazed carbide bars?
I just picked up a nice used Critereon boring head for about the cost of a new import. That's the way to do it in my opinion.
Very good review, thank you!
I like my Criterion, but the Shars (and other copies) are much cheaper and do a great job. I would put my money into the boring bars and carbide. Thanks for the video!
FYI in 2021, this Shars kit is discontinued.
Appreciate the thorough video, really well put together. I have the shars version but haven't had the opportunity to try out a criterion. I'm sure there's a time down the road when I'll need to spend the money to get that last 5% from the criterion, but it's good to know that the shars isn't holding me back much :)
I will and thanks again for the video
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So we cant use it (counter?)clock wise or left, because it will unscrew
There is the possibility of that happening, yes. A lot of boring heads have a set screw of some kind to lock it in place. Not so for thus one, but it could probably be added.
Great video Stuart!
Nice, subscribed!
How much backlash do you have on the adjusting screw? It looks pretty tight on that head watching you turn it. Just curious because I just got a 3" head and its got about .015" of backlash.
I just checked and it looks like about .0035" or so. It's not a lot, but backlash shouldn't matter in practice, since all of your adjustments should be in one direction. If you do accidentally go too far, just turn back a ways to remove the backlash and then re-approach.
Doesn’t a radius reading dial cut the resolution and accuracy in half?
Pretty much. I was pretty surprised by that, especially since it says diameter on the dial.
@@StuartdeHaro thank you for your quick response. I’m a hobbiest and know nothing. So I truly appreciate your videos
@@genecarden780 Feel free to ask me any questions you may have. I'm happy to help.
@@StuartdeHaro you don’t have enough time in the day to answer all my questions 😜 but I will ask when I can’t find answers thank you. But here’s one that has always bugged me. How can a surface grinder be so accurate when it’s cutter is friable
@@genecarden780 That’s an excellent question. First of all the leading edge of the wheel will break down first, so feeding from both directions (front to back) helps keep the wheel reasonably flat. Dressing the wheel a bit before the final cut helps with accuracy as well, especially if you've had to remove a lot of material. Measuring the part is key to knowing how much wheel wear to account for. Lastly let the wheel spark out at the end for the best finish and flattest part.
Nice video. What model is the Criterion head, and is it direct-reading? How much does the diameter change per revolution of the dial? I'm looking for a boring head which cuts .050" on the diameter per turn of the adjusting dial. That would require a lead screw of 40TPI, instead of 20TPI like the Shars head.
Not sure on the model number, but it is a 2" boring head and it does read on the diameter.
It's a DBL-202 --- They are often for sale on EBay, but you can also get them brand new condition from tool sellers like Traverse.DBL-202 moves .050 per revolution of the dial (I just went down into my shop and looked at my Criterion). You're probably not going to find a boring head that cuts .050 on the _diameter_ !! Just buy a Criterion and be done with it. They have been in used in machine shops since at least the early 1940's (what does that tell you?) BTW I'd NEVER buy a Shars !
thanks for the info on the boring heads thumbs up
learned a ton...great video.
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NEVER EVER thighten or loose tools inside the spindle...
NEVER TIGHTEN IN THE SPINDLE EVER!!!!!!
NEVER TIGHTEN WHAT IN THE SPINDLE? AND WHY ARE WE YELLING?
@@StuartdeHaro yelling because that's what happens to apprentices who tighten ANYTHING in the spindle....
You refered to tightening the boring head to it's r8.... In the spindle with a strap wrench...... Any apprentice will tell u that's a no no
The shaft is loose (just hand fit) because they sell these with mt3 as well as r8 shafts, and often change them over. They are trivial to tighten and in any case will self tighten the first time you use it as you note so i dont understand why you want to crank down on it or use thread lock. Or are you one of those people that hammers morse tapers home with with a sledge and uses thread lock on those too ?