Making bushing & pins for a JD Dozer

[Cabro32]

My son-in-law got what he though was a good deal on a toy. He tore the very worn 6 way dozer blade off it and called the local machine shop to give him an estimate on making pins and bushings for the blade and mounting fixtures. First bid was $6,000.00 and the second bid was $4500.00 which was more than what he paid for the dozer. So he packed up the machine and dropped it off at my place and said can you bail me out. All the pins are severely worn and the holes are egg shaped. The bushings that are still left are falling out of the bores.
So, I guess I have my first machining project and have many questions. I have a Colchester 15x48 round nose lathe and a J-head Bridgeport mill up and running.

Questions:

1. Local machine shop said they use 4140 steel to make pins and bushing because it is already heat treated but still machinable. Is this a good choice?

2. For a press fit how much oversize should the OD of the bushing be ?

3. How much undersize should the pin be to the ID of the bushing ?

Thanks for the help, many more questions to follow.

 

[dirty tools]

Do not press fit the bushing in WELD them in place, and make sure they are square. The job will be easier, and you can make the outside diameter to fit and all pins the same size.

 

[Mark R R]

I have replaced the entire pin and brackets on all the blade braces on a D6D I used to own. We rebushed the braces to match the new pins, all with 4140. We pressed the bushings in with a .003 interference fit. That was about 5000 hours ago. Nothing has budged yet.

 

[DAN_IN_MN]

Looks like you got the answers!

Are you going to have your son-in-law help with this project?

 

[Maxx]

If you weld them in you will have to ream them afterwards because they will distort.
The ones on my Case are press fit.

 

[Cabro32]

Thanks all for your help. Since this is a learning project I want to go the press in bushing route. Yes my son-in-law will be helping as he wants to learn also.
Thanks,
Joe

 

[Cabro32]

Question on blade mounting bracket. The first 2 pictures shows a worn 2" out of round hole which takes a 6" long pin. If you look at the first picture and through the top hole you can see the wear in the bottom hole. I intend to build up the worn area with weld. The top hole is also worn.

Questions:

1. Picture 3 shows a boring head and 3/4" various length boring bars. Is this a suitable tool to
mill the ID of the hole or should something else be used?

2. How do you find the center of a out of round hole or I should ask how should this be setup in a mill so the hole ends up in the original spot?

Thanks
Joe

 

[DAN_IN_MN]

I wonder if you used the OD of the bushing would that be close enough?

 

[flutedchamber]

I made pins and bushings for my 680CK loader. The pins were made from A2, drilled and tapped for grease fittings and distribution holes. They were then tempered and drawn back to remove any brittleness.

The bushing were made from A2 and left as is. They were made to a .002 press fit in the bores. I ran a .005 loose fit between the pins and the bushings. They have worked fine for years now.

 

[Cabro32]

Re: Making bushing & pins for a JD Dozer

I wonder if you used the OD of the bushing would that be close enough?

Hi Dan:
Good idea but problem is there is no bushing used. Pin in bracket with no bushing used.

- - - Updated - - -

I made pins and bushings for my 680CK loader. The pins were made from A2, drilled and tapped for grease fittings and distribution holes. They were then tempered and drawn back to remove any brittleness.

The bushing were made from A2 and left as is. They were made to a .002 press fit in the bores. I ran a .005 loose fit between the pins and the bushings. They have worked fine for years now.

flutedchamber:

Good info ,would expect that from Festus!!! Thanks