machinist@lists.ibiblio.org
Subject: Machinist
List archive
- From: Lawrence London <lfljvenaura@gmail.com>
- To: machinist@lists.ibiblio.org
- Subject: [machinist] inside mics @ boring bar?
- Date: Thu, 27 Feb 2014 11:38:18 -0500
http://www.practicalmachinist.com/vb/general/inside-mics-boring-bar-280661/
Thread: inside mics @ boring bar?
-
inside mics @ boring bar?
Hello,
I'm going to buy a set of inside mics. I have been using the starrett 2-12" with good results. The question I have is, "Are the barrel mic's better?" If so, why? How does the Mitutoyo stuff compare to the Starett?
My other question is regarding a boring head. Most of what I do is in aluminum. But, I have a few air cooled cylinders to bore. They are cast iron. The boring head that I have used had a hardened tool that did the cutting. Will this work on cast iron, or do I need to buy a set with inserts.
I'm looking to spend about a 150-200 bucks. (on the boring head) If anyone can make a recommendation on something that they have used and works well I appreciate.
New to all of this. Made a faze converter. LOVE ALL OF IT!!!
Thanks in advance, be safe. schick -
02-22-2014, 11:22 AM #2
- Join Date
- Mar 2013
- Location
- Danville Virginia
- Posts
- 25
I know what a micrometer barrel is, never heard of a barrel micrometer. Are you thinking of a dial bore gage maybe? What type of machine are you boring these on and style/type of a boring head are you referring to?
-
The best inside micrometer I've ever used is the Mitutoyo 4"-52" set. A shop I worked in had a set and they were so good I bought a set brand new (over $800 iirc). They are made of good sturdy thick walled tubing with insulators down the whole tube length, and screw together, with ground faces at the interface - so it's almost like screwing standards together. The mic head is super smooth, and the contact surfaces are carbide. Absolutely fantastic inside mic. The downside is the cost and the fact that they start at 4".
Edit: this is the type of mic but my set goes to 52":
Mitutoyo 4 20" Tubular Inside Micrometer Set New Save $480 00 Ships Worldwide | eBay -
02-22-2014, 08:42 PM #4
- Join Date
- Mar 2007
- Location
- Far Northern California, USA
- Posts
- 1,222
The Staretts are ubiquitous but not my favorite bore gauges. The Mits are much much better. If you are doing a lot of bore get yourself a self-centering dial bore gauge. Both the Mits and the Staretts are pretty entry-level try Mahr or Sunnen. Diseno is a popular import but I don't know how good they are.
A lot of a lot of cast iron bores were done over the decades with the high carbon tools. Carbide will hold tolerance a long longer however. What machine are you doing the bores on? Are you looking for fixed size heads like take a micro-adjust cartridge or something more universal? -
02-22-2014, 09:05 PM #5
- Join Date
- Nov 2012
- Location
- Illinois, USA
- Posts
- 57
I have been using the Starett 2"-12" inside mikes for about two years now and they are VERY accurate when used properly. We had a set of Mitus and they were just worn out so we replaced them with the Starett set and I am pretty happy for now.
As far as the boring head is concerned, you will be time, frustration, and money ahead adapting the head to fit a indexable type cutter to do any cast iron as the material is abrasive and likes to chip off hand cutting tools that are sharper that most inserts. I have a boring head that takes a 3/4" boring bar, cut shorter that uses TPG321 inserts for boring smaller cast parts with excellent results. You can't take heavy cuts but the surface finish is good, and accuracy is as good as to be expected with a boring head. Just my $.02 -
What l am boring is the cylinders of a Wisconsin engine. When l was in the business, l would use the sunnen boring bar and fixture. But no longer have that aviable. So just want to do a set of cylinders at home, rather than pay to have it done
I will give the Mits a try. 2-12 with the barrel style are are around 200.00.
One other question reguarding the alignment of the boring bar in the head.
How do you set the best angle of the cutting tool? Or maybe a better question would be what is the best angke for cutting cast iron?
Thanks for your input. Be safe, schick
Yes, boring head will be used. Missed that in my first thread. Thinking 3" to get the .750" boring bars.Last edited by schick; 02-26-2014 at 10:34 AM.
-
Enco knee mill.
Originally Posted by starbolin
The Staretts are ubiquitous but not my favorite bore gauges. The Mits are much much better. If you are doing a lot of bore get yourself a self-centering dial bore gauge. Both the Mits and the Staretts are pretty entry-level try Mahr or Sunnen. Diseno is a popular import but I don't know how good they are.
A lot of a lot of cast iron bores were done over the decades with the high carbon tools. Carbide will hold tolerance a long longer however. What machine are you doing the bores on? Are you looking for fixed size heads like take a micro-adjust cartridge or something more universal?
Thanks, schick
Reply
- [machinist] inside mics @ boring bar?, Lawrence London, 02/27/2014
Archive powered by MHonArc 2.6.24.