bushing sizes

[Bruce Barnes]

I have a sizing guage (one of the small ones) and the pivot fits the 220 hole,yet opposite it,there is the number 170.Are they the equivalent and I should use the 1.70 bushing or the 2.20? I dont know how thick the wall is and it appears that to go from 1.70 to 2.20 is one long reach.

These are the KWM bushings.

Thanks for the help,
Bruce

[Joseph Bautsch]

I have no idea what those numbers mean. ??? Bushings are measured by; Height, Bore, and Diameter. What is the thickness of the plate? KWM Bushings come in heights of 1.0mm, 1.4mm, 1.7mm, 1.9mm, 2.7mm, 3.0mm, and 4.0mm. Referring to the KWM bushing chart you have to decide what height to use first. Example, if the thickness of the plate is 1.4mm with a pivot diameter of 2.20mm then you could use either a L23 or a L70 in KWM. The L23 has the same bore as the pivot and will have to be broached out to fit. The L70 has a bore of 2.3mm, a close fit, and would require less work. You can find a KWM bushing chart in The Time Savers catalog. It also gives you which reamer is needed with each bushing. It's rare to have the exact thickness in plate and bushing the same. Always pick a bushing that is a little more in height than the plate thickness. Never one that is shorter. You then, after the bushing is pressed in, use an end cutter to cut down the height of the bushing to the plate level. Maybe someone else has used a sizing gage and can give you more information.

[Joseph Bautsch]

I have no idea what those numbers mean. ??? Bushings are measured by; Height, Bore, and Diameter. What is the thickness of the plate? KWM Bushings come in heights of 1.0mm, 1.4mm, 1.7mm, 1.9mm, 2.7mm, 3.0mm, and 4.0mm. Referring to the KWM bushing chart you have to decide what height to use first. Example, if the thickness of the plate is 1.4mm with a pivot diameter of 2.20mm then you could use either a L23 or a L70 in KWM. The L23 has the same bore as the pivot and will have to be broached out to fit. The L70 has a bore of 2.3mm, a close fit, and would require less work. You can find a KWM bushing chart in The Time Savers catalog. It also gives you which reamer is needed with each bushing. It's rare to have the exact thickness in plate and bushing the same. Always pick a bushing that is a little more in height than the plate thickness. Never one that is shorter. You then, after the bushing is pressed in, use an end cutter to cut down the height of the bushing to the plate level. Maybe someone else has used a sizing gage and can give you more information.

[clockdaddy]

Bruce,
I tried to use the gage over 15 years ago when I was starting out. All it does is complicate a simple process. Give it to someone else or throw is away is my suggestion.
Joseph is giving you some real good info. Yes, it looks and may sound confusing. I had to slow down, when I was learning about the bushings, and concentrate as to how everything corresponded with everything else.

In short, the reason you have a variety of bushings is so that you can choose the bushing that is closest to the size of the pivot (a little smaller is better), is at least as tall as the plate is thick and based on these two results you can determine what size cutter to use for the hole.

If anything confuses you we're all here to help. We each have our own way of saying things and sometimes you may have to be told two or three different ways until something clicks and you'll suddenly understand. (Kinda scary, isn't it!!!)

Let's get clockin'

Harold Markey NAWCC #0124626

[Bruce Barnes]

Thanks Harold,
The pivot size, according to the "scale" is 220 and I have a 190 bushing,is their enough "meat" on the bushing to remain as a servicable bushing after it is sized properly?
Regards,
Bruce

[Joseph Bautsch]

I don't think you will have enough bushing wall left to make a long lasting job out of it if it works at all. In the example I gave you the diameter of the number #IV reamer is 3.5mm and the largest bore listed for that reamer is 2.8mm. The difference is .7mm. From there you have to change diameter of the bushing to a larger one. This is true for all heights of bushings listed. The bushing you want to use will have a wall thickness, after broaching out to get a fit, is .3mm or less. (2.20mm - 1.90mm = .3) The "or less" depends on how much broaching you need to do. That is less than half the size of wall thickness used by the manufacturer even for the largest pivot, 2.8mm, for this series of bushings. It sounds like you don't have a vernier caliper. If not get one. If you do any amount of clock work you can't live with out one. That will allow you to take measurements of pivots and plate thickness and a lot of other measurements you need in clock work.

[clockdaddy]

Bruce,
I'm totally against using any thin wall bushings. I'd rather go on to the next cutter size. A thin wall bushing will distort when being pressed in. Then in order to get it to work, you must broach it some making it even thinner.

Going to the next size cutter and pivot gives a strong walled pivot that will mot distort and you can broach as needed without worrying about breaking through the bushing wall. The larger bushing also give a better look to the plates showing it was properly repaired.

Harold Markey NAWCC #0124626

[Bruce Barnes]

Gentlemen,
Thanks for your input and guidance.I will use a #4 reamer and then use the "more" correct size bushing and then broach to finish.
I used a loop and Micrometer to check more closely, and to go the other way would have been "skating on thin ice" !!
Regards,
Bruce

[Jeff C]

Not sure if this is correct practice but by hand I just find a bushing that fits the pivot then I use that one, along with a reamer that is slightly wider to cut the hole. Usually have to broach the hole afterwards since pressing the bushing in seems to always shrink the hole a bit.

[clockdaddy]

Jeff,

There's nothing wrong with the way you're doing bushings. The outcome we all want is to have the pivot fit properly. If you are able to do this, whose to say it's wrong??

There are many methods that work. That method workd easiest for you...stck to your comfort zone!!

Harold Markey NAWCC #0124626

[Joseph Bautsch]

Guys - A bushing that is a press fit into a hole cut by a reamer will have a smaller bore. It's compressed to some degree when it is pressed in. So a bushing that is a close fit on a pivot before it is pressed in probably will not fit after. (It depends on how close the fit is before being pressed in.) It's a matter of physics. Two objects can't fit in the same space at the same time. The bushing is a little larger in diameter than the hole the reamer cuts. Something has to give when it is pressed in. The plate will give very little. It's the bushing that gives in the most, in toward the bore making it smaller.

The method I use to find the correct bushing is open the box of bushings with the height I need and see which one has a close fit to the pivot. The box is marked with the correct reamer to use. Why make a simple task hard.

[clockdaddy]

Joseph,
Maybe I misunderstood, but I think he was talking about the diameter of the pivot and pivot hole relative to each other.

The size of the bushing diameter and the cutter hole are a predetermined factor.
The cutter is always a few thousandths shy of the diameter of the bushing.

Harold Markey NAWCC #0124626

[Joseph Bautsch]

I just figured out where that dude with the eye patch came from. He was not intended. I typed a period with a close parenthesis and that generated that little guy. I'll have to remember not to do that again unless intended. +o(

[Joseph Bautsch]

Usually have to broach the hole afterwards since pressing the bushing in seems to always shrink the hole a bit.

CD - This is what I was explaining.

[Jeff C]

Well I would use numbers to match these but in my case I see no numbers on my hand reamer tools and when I bought bushings they were a mixed assortment so I just separated them according to a visual look at them. Actually I put them in one of those daily pill boxs.

[clockdaddy]

Joseph,
Thanks, I appreciate you setting me straight!! Hey, leave the little guy alone...he's kinda cute!

Jim, the cutters don't have numbers on them. I guess the producers couldn't count!!

Harold Markey NAWCC #0124626

[Jeff C]

CD, what do you look for when it says use a No.3 Reamer for example? Also the rather fat one ( chemfering ) I use that to cut the oil sink if needed, is that OK?

[clockdaddy]

Jeff,

Yeh, the large one (probably a 1/2 " diameter) is for the chamfering of your holes.
The other cutters become second nature as to which one to grab (and I have grabbed the wrong one!!)'

Harold Markey NAWCC #0124626

[Joseph Bautsch]

CD, no offense intended. I guess I should have used a :).

It's a good idea to chamfer the hole after reaming it out. Makes it a lot easier to get the bushing pressed. It's a real dumb dog trick to crawl around on your hands and knees looking for a bushing that popped off the plate hole while trying to press it in. It took about two times of that and I remembered to use the chamfering tool.

I guess I'm slow but I still have to line up the reamers by size. "The little one is #1, the next one is #2 and so on". Maybe one day I'll make a little wooden block with holes in it to keep all the tools in line.

[clockdaddy]

CD,

It's a real dumb dog trick to crawl around on your hands and knees looking for a bushing that popped off the plate hole while trying to press it in.

I guess I'm slow but I still have to line up the reamers by size.


Joseph,

I've done a lot of floor time, too.It's amazing how far those little suckers can go. Oh, You can swear that it went to your left, but for some reason it lands somewhere on your right.

You're in good company with the reamers in having to line them up! I did finally drill out a holder for them and labeled the holder. At least I know what's "supposed" to be there...

Harold Markey NAWCC #0124626

[Jeff C]

CD,

Congrates on tacklin that quote process :)

[clockdaddy]

CD,

Congrates on tacklin that quote process :)

Thanks Jeff,

All the credit goes to Jeff Hamilton. Can you imagine the hours he has spent helping us to learn this new board??

He's something else.

Harold Markey NAWCC #0124626

[clockdaddy]

CD,

Congrates on tacklin that quote process :)

Thanks Jeff,

All the credit goes to Jeff Hamilton. Can you imagine the hours he has spent helping us to learn this new board??

He's something else.

Harold Markey NAWCC #0124626