# Cut off blades, Inside diameter measurments, and backhoe woes



## TIB (Apr 6, 2013)

And can someone tell me how to get accurate inside diameter measurements? Am turning bushings for an OLD (1965) Case backhoe, and am having a hard time getting accurate inside measurements on the holes I've bored. 

I've gotten to the point of turning a round stock a few thousands under the desired size, then inserting it into the bored hole. Using feeler gages I can a size and turn a bushing to fit. But this is a painfully slow process.

FYI. Have been honing the inside of the bore to get the surface smooth, andusing 220 grit emery cloth on the OD of the bushing to get its surface smooth.

Also

I've noticed there are different "P" series ofcut off blades. For example P3 and P4 Both have the same width, height andlength. What are the differences?


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## Ray C (Apr 6, 2013)

As far as bore measurement, ball gauges or ID telescoping gauges work pretty well for 90% of my tasks.  If you take your time with these, you can easily measure into the half-thou range.  Once you fit the gauge inside the bore, you remove it and measure with a regular mic.  These are from Shars.com...

If you really need to get the inside of a bore smooth and even, you'll have a hard time with emery cloth.  If you can, set it up in a lathe or mill and power-ream it.  That's the 1st line of defense.  Next takes some specialized stuff such as an internal post grinder.  There are various designs ranging from expensive versions of a dremel tool to adapter shafts on traditional tool post grinders.

Ray









TIB said:


> And can someone tell me how to get accurate inside diameter measurements? Am turning bushings for an OLD (1965) Case backhoe, and am having a hard time getting accurate inside measurements on the holes I've bored.
> 
> I've gotten to the point of turning a round stock a few thousands under the desired size, then inserting it into the bored hole. Using feeler gages I can a size and turn a bushing to fit. But this is a painfully slow process.
> 
> ...


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## valleyboy101 (Apr 6, 2013)

I agree with Ray.  For work the size of the pins in a backhoe I would use telescoping gauges and then measure with a micrometer or at a minimum a caliper.  The ultimate would be an inside micrometer but you probably don't need that degree of accuracy.
Michael


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## TIB (Apr 7, 2013)

Thanks for the reply and help. Probably should explain that I was talking about the OD of the bushings for the pins and the ID of holes I bored. In this present situation I’m working on the outriggers. The machine did not have bushings in the outrigger brackets originally, and the wear made boring necessary.

I’m using O1 drill rod hardened then tempered for the bushings, and old hydraulic cylinder rams for the pins. Don’t know how well either will last, but the machine only gets 100 to 200 hours a year on it. The only reason I cleaned up the OD of the bushing and the ID of the bored hole is so the mating surfaces have more consistent contact areas.

This afternoon I did set down and practiced with the telescopic gage, but still could not get closer than .003 consistently. I am checking the telescopic gage with a 1 to 2” micrometer. 

I think it will take more experience on my part to get very accurate with the telescopic gage.

The bushings are hard enough that they don’t seem tocompress when pressed into place.

Just FYI I’m working with 1-1/2 to 2 inch pin size. 

Thanks again for the advise,
Tom


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## Ray C (Apr 8, 2013)

I gotcha now...  You're drilling the frame of the machine and will stuff a bushing in there then, a pin goes inside the bushing...  If that's the case, the hole you drilled is probably pretty rough.  Is there any chance you can ream that hole to clean it up?  If so, you won't need to measure the hole when you're done because it will just be the size of the reamer you used.  Reamers are only good for taking off 2-3 thou so get the hole undersized but close and use the reamer to straighten and get the ridges out.

What is the bushing material made of?  If it's brass or bronze, it should go inside the hole without too much fuss.

The ball and telescopic gauges take a little practice.  You must hold the shaft straight.  One end is wider than the the other.  Compress the gauge, insert in the hole, release the telescope, hold it straight and steady while tightening then, tip it out so the skinny end of the telescope comes toward you.  That way, it won't compress it.  If you tip it toward the fat end, it will compress a little.

Ray




TIB said:


> Thanks for the reply and help. Probably should explain that I was talking about the OD of the bushings for the pins and the ID of holes I bored. In this present situation I’m working on the outriggers. The machine did not have bushings in the outrigger brackets originally, and the wear made boring necessary.
> 
> I’m using O1 drill rod hardened then tempered for the bushings, and old hydraulic cylinder rams for the pins. Don’t know how well either will last, but the machine only gets 100 to 200 hours a year on it. The only reason I cleaned up the OD of the bushing and the ID of the bored hole is so the mating surfaces have more consistent contact areas.
> 
> ...


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## Tony Wells (Apr 8, 2013)

Ray, I have to disagree with your method of using the telescoping gages.The idea is to deliberately set them at a slight angle in the bore, then lightly snug the lock up on them, then pull the handle towards you to compress the telescoping sections until they are exactly the same length as the bore diameter. This happens only if you "sweep" it through the bore. This causes them to self-center in the bore radially, and match the bore perfectly. Of course, a large part of the accuracy you get is just how tight you run the locking rod by turning the end section of the handle. Too tight and you either won't be able to move the gage through that short arc section, or too loose and it won't self-center or won't hold the measurement. You'll never get accurate results guessing at the proper position and then locking the gage for a measurement. It's easy to get within a couple of tenths if you use them right. I'm sure there is a youtube vid of it. If not, someone should make one. Mit makes the best telescoping gage, hands down. Smoothest action. The probably have some instructions in their catalog, too.


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## TIB (Apr 15, 2013)

Ray I'm finally able to get back on to let you know that I've finally gotten the ID readings to be consistant. Found that when tightning my telescopic gauges they were changing. When tightened enough so the micrometer's ratched would not compress the gauge, the gauge moved from the origional position.......guess you get what you pay for. 

Ordered a new set of brand name telescopic gauges and can get consistant readings. 

By the way I missed the part of your question about what the bushings were made of. I'm using drill rod. Am hardening it and then tempering. Maybe this will keep them from cracking.

You are right about the grinding etc. I'm hoping that working them through to 2000 sand paper then polishing with a buffing wheel on a rotary sheet rock cutoff tool will get them smooth enough to last a few more years.

Thanks again for the help and support.

Tom


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## Tom Griffin (Apr 16, 2013)

Telescoping gauges definitely require some practice to learn how to measure with them with any consistency. As Tony pointed out, the proper way to use them is to hold the handle at a slight angle to the centerline of the bore, snug up the lock a bit and sweep the gauge through the center of the bore. I like to wiggle the handle a bit to help the tips of the gauge to find the largest point on the bore. Once you do the sweep thing, you must resist the urge to tighten the gauge since any telescoping gauge can move after taking a measurement if it's tightened. The tightness of the lock is not as critical as you might think. Practice on a bore and try tightening the lock different amounts so you can see how it affects repeatability.

Tom


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## Ray C (Apr 16, 2013)

Tom:  I'm glad you're making some progress.  Just a quick note of due caution...  If these are for bucket pins or something similar, be cautious about home made parts. A sudden snap can injure people.  If this is for your personal equipment and you don't intend to lift the Rock of Gibraltar, you can gradually test the equipment and gain confidence.   Stuff like bucket pins are where careful metal selection and heat treating etc play very important roles.


Tony:  I'll try that method.  Sounds good.  Over time, I've managed to get pretty consistent and successful readings with my home brew technique but, I'm not too old to try/learn new tricks.

Ray




TIB said:


> Ray I'm finally able to get back on to let you know that I've finally gotten the ID readings to be consistant. Found that when tightning my telescopic gauges they were changing. When tightened enough so the micrometer's ratched would not compress the gauge, the gauge moved from the origional position.......guess you get what you pay for.
> 
> Ordered a new set of brand name telescopic gauges and can get consistant readings.
> 
> ...


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## TIB (Apr 17, 2013)

Ray you are right on the nose about "Homemade Parts", they are not to be trusted. This is a machine I use on the farm only, and would never do something like this for anyone but me, and if pins and bushings were still available from Case it would have been less expensive to purchase them, even considering that my labor is fairly inexpensive.

For the pins I've used 4340 and 4140. Have not made any attempt to harden them. I hope they wear and produce enought slop that before they break the machine is not usable.

I've had machine for over 20 years, and don't use it enough to warrent anything newer, nor do want to sell as a working machine. Even selling "as is where is" over the years I've done so many repairs I'd hate to be responsible for something going wrong at a critical moment. It's sad, but I don't think you can get away from liability on anything that has the ability to "overhead" lift even years after the fact.

Tom


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## Ray C (Apr 17, 2013)

OK Tom, you got your head on straight.  I'm relieved you didn't get offended.

I'm not sure where the lines are drawn about liability for used equipment.  -And I'd sure hate to find-out the hard way!  I've had folks ask me to repair trailer hitches...  Even had a guy ask me to fix a tie rod (which could be replaced for 30 bucks).  ...Haeeeck no!

43 and 4140 is good stuff!  Both are considered "low-end" tool steels which translates to "high-end" manufacturing steel.  If you ever find-out the precise heat treatment that the factory pins have, please let me know.  I'm really curious.

Ray





TIB said:


> Ray you are right on the nose about "Homemade Parts", they are not to be trusted. This is a machine I use on the farm only, and would never do something like this for anyone but me, and if pins and bushings were still available from Case it would have been less expensive to purchase them, even considering that my labor is fairly inexpensive.
> 
> For the pins I've used 4340 and 4140. Have not made any attempt to harden them. I hope they wear and produce enought slop that before they break the machine is not usable.
> 
> ...


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## jmh8743 (Apr 17, 2013)

I also have a Dahatsu loader, 45C...Pins and bushings, Yuck. right now my high $ loader is worthless.
For me I gave up on those telescoping gauges when i worked on race car engines. i use a dial bore gage, works well for even me. Found several on the ebay.
hardening low carbon steel, just to consider, bought mine 10 yrs ago, I quote:

Kasenit provides an easy way to harden soft, low carbon metals without the use of special equipment.  Kasenit in  combination with high heat creates a tough, durable, hardened finish on  the surface of metals.
Great item for blacksmith, machine shop, welding shop, hobbyist, gunsmiths, antique & tractor restoration shops.  Helps keep the edge sharp on expensive drill bits, milling and grinding  tools, punches, firing pins, hammer davits, trigger pins, sears, and  cocking pieces.
Produces a wear surface (surface hardening) on low carbon steel, low alloy steel, iron.
non-poisonous, non-explosive.
*Application instructions (from Kasenit) for Low Alloy or Low Carbon Steel:*
There are two methods of application.
Method A: Heat the work uniformly to a bright red (1650 - 1700 degrees F), remove any scale with a wire brush, dip, roll or  sprinkle the Kasenit powder on the component. The powder will melt and adhere to the surface, forming a shell around the  work. Reheat to 1650 - 1700 degrees F, hold at this temperature for a few minutes and quench in to clean cold water. This  will give the component a completely hard case of uniform character and depth.
Method B: If a deeper case is required, then a container for the compound can be used. A discarded can, lid or tray is  suitable for this purpose, but care must be taken to burn off the tin coating before use. Completely cover the component  with compound and heat to a bright red (1650 degrees F) for five to thirty minutes, depending upon the depth of case  required. Quench only the component in clean, cold water unsing dry tongs for handling. 

Mike in Cullman
My grandaddy was a blacksmith

Disclaimer: I do not benefit in any purchase of a Kasenit product. Futhermore, the by product of the reaction is similar to cyanide gas. Use it in the open or vented.


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## Kevin45 (Apr 28, 2013)

One other thing you can do instead of using telescoping gages, is to turn a plug gage. Make it long enough to be useful to yourself. On one have of the plug make it to the size you need. On the other end, turn it down .005 smaller. You can now sneak up to your final size knowing you have .005 to play with. Cheap and easy.


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## cross thread (Apr 28, 2013)

Hi TIB ,  I don't know the situation  you are using the bushings nor did I read every single post here. So I don't understand why you would 
be using hardened 01 . My choice would be oilite or just bronze or brass . With clearance of .003 + .001 -.000. Also your question about the P type cut off blades is a good one, and 
I couldn't find a good answer . If someone already did, sorry . I always had better results with the P types , because of all the relief angles . 
I always used the Colbalt .


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## TIB (Apr 30, 2013)

cross thread said:


> Hi TIB ,  I don't know the situation  you are using the bushings nor did I read every single post here. So I don't understand why you would
> be using hardened 01 . My choice would be oilite or just bronze or brass . With clearance of .003 + .001 -.000. Also your question about the P type cut off blades is a good one, and
> I couldn't find a good answer . If someone already did, sorry . I always had better results with the P types , because of all the relief angles .
> I always used the Colbalt .



The main reason I've used hardened bushings and softer pins is to keep the wear in the pins and bushings rather than the frame of the backhoe. I've know of Skidders using plastic bushings in the grab, but am not aware of any brass or composite materials being used in backhoe or loader applications. Would sure rather work with something more forgiving than 01.

Some positions had factory installed bushings, and in some positions the pins worked directly against the frame. Where bushings are used, the old bushings only get shined up when filed.

Thank you for your help and reply
Tom

- - - Updated - - -



Kevin45 said:


> One other thing you can do instead of using telescoping gages, is to turn a plug gage. Make it long enough to be useful to yourself. On one have of the plug make it to the size you need. On the other end, turn it down .005 smaller. You can now sneak up to your final size knowing you have .005 to play with. Cheap and easy.



I gave up on the telescopic gages I had and went to plug gage approach, found that using feeler gages with the plug gage worked fine for this application. After some sage advise from Ray C and Tony I bought a set of name brand telescoping gages and they have worked very well. Maybe it was all in my mind, but the new set seem to work much better than the old Harbor Freight gages. 

Thanks for taking the time to reply.

Tom


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## TIB (Apr 30, 2013)

jmh8743 said:


> I also have a Dahatsu loader, 45C...Pins and bushings, Yuck. right now my high $ loader is worthless.
> For me I gave up on those telescoping gauges when i worked on race car engines. i use a dial bore gage, works well for even me. Found several on the ebay.
> hardening low carbon steel, just to consider, bought mine 10 yrs ago, I quote:
> 
> ...




Mike I appreciate the informatin and am going to save it! 
Tom


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## eightball (Apr 30, 2013)

I like the starrett telescoping guages that have one fixed side and only the smaller side moves. I get a better feel with them than i do with the ones that telescope on both sides. Dont know the starrett no. off the top of my head, will look tomorrow if i get a chance.


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## eightball (May 2, 2013)

They are starrett # S229G.


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## onecut jimmy (May 4, 2013)

Eight Ball I understand your problems To me they are all minor .But I have 70 plus years experience .
In 1942 I started taking a machinist class in high school, In 1944 I stared my machinist apprenticeship, in 1948 I got my journeyman papers. In 1950 I started my Tool & Die maker apprenticeship . In 1954 I got my journeyman papers. During those years i went to night school to get my mechanical engineer s degree.

lET'S START WITH THE PIN & BUSHING PROBLEM  IMO The bushings should be made of bearing bronze or tobin Bronze. The inside should haveoil grove with a hole to the outside for oiling. 
If you could give me a sketch of the pin & bushings, I ccould tell you what materials to use and what th heat treat , The hole size, the pin diameter etc.
As fo the use of telescoping gauges. Machinist use them all the time. Their accuracy depends on your ability to use them. I started without inside mics, telescoping gauges, dial calipers etc. I had to use inside calipers and outside mics to measure holes.  Can you explain how you are using telescoping gauges. 
I will tell you most people use them wrong. Do you know they are self centering?
If you PM me your phone number I will call you and explain how to use them.


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