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question for all you machinists out there

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h.d.ryder

Posts: 298

Joined: Sun Nov 10, 2002 1:01 am

Location: Cranbrook B.C. Canada

Post Sat Jan 10, 2015 12:02 pm

question for all you machinists out there

I have a 39 ULH that needs a set of cam bushings in cover & case half. Can I set up the case half and the cam cover sise by side on mill table and dial in each bushing then bore each bushing with proper clearance for my cams and oil pump etc. I`m hoping that this method is as good as align reaming with proper reamers? because no-one seems to sell the proper reamer set anywhere.
Thanks in advance.
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Pa

Site Admin

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Location: Ohio USA

Post Sat Jan 10, 2015 1:20 pm

Re: question for all you machinists out there

If your new bushings wall thicknesses are consistent in wall thickness size all over and you also indicate to the gasket surface, yes you can.
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h.d.ryder

Posts: 298

Joined: Sun Nov 10, 2002 1:01 am

Location: Cranbrook B.C. Canada

Post Sat Jan 10, 2015 11:20 pm

Re: question for all you machinists out there

Thanx Pa, that`s what I needed to know.
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woody

Posts: 514

Joined: Mon Apr 15, 2002 12:01 am

Location: Wa, USA

Post Mon Jan 12, 2015 7:46 pm

Re: question for all you machinists out there

I machined a plate that bolts onto both the case and the cam cover using the dowels for locating. It has holes bored in it with enough room to bore the case and cover through it and they are located in the correct locations. I can dial each hole in and they will match when done.
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h.d.ryder

Posts: 298

Joined: Sun Nov 10, 2002 1:01 am

Location: Cranbrook B.C. Canada

Post Mon Jan 12, 2015 8:57 pm

Re: question for all you machinists out there

woody wrote:I machined a plate that bolts onto both the case and the cam cover using the dowels for locating. It has holes bored in it with enough room to bore the case and cover through it and they are located in the correct locations. I can dial each hole in and they will match when done.



How thick is the plate? 1/2" ? Any chance you can post a picture of the jig?
Thank you.
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Pa

Site Admin

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Location: Ohio USA

Post Tue Jan 13, 2015 7:43 am

Re: question for all you machinists out there

I would suggest a good one inch plus thick plate so you can mill both faces of the plate parallel to each other. The heavier plate will reduce the chance of vibration and chatter as well. I have a pic of a setup posted on this forum many years ago for use on a horizontal milling machine. I will look for the pic for you and put it up.
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Pa

Site Admin

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Post Tue Jan 13, 2015 8:12 am

Re: question for all you machinists out there

I found the pics quicker than I imagined I would. I don't recall which member built this setup but I thought it was brilliant.

Image

Image

Image
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h.d.ryder

Posts: 298

Joined: Sun Nov 10, 2002 1:01 am

Location: Cranbrook B.C. Canada

Post Tue Jan 13, 2015 6:59 pm

Re: question for all you machinists out there

Wow! That`s an awesome set-up. Someone has a few hours tied up in that project. Thanks for posting and giving me some ideas.
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woody

Posts: 514

Joined: Mon Apr 15, 2002 12:01 am

Location: Wa, USA

Post Tue Jan 13, 2015 7:01 pm

Re: question for all you machinists out there

I used a 1 inch thick aluminum plate big enough to screw the cam cover to and clamp in a machine vise.
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h.d.ryder

Posts: 298

Joined: Sun Nov 10, 2002 1:01 am

Location: Cranbrook B.C. Canada

Post Tue Jan 13, 2015 11:30 pm

Re: question for all you machinists out there

Looks like I`ll be checking out the local salvage yard ,looking for some 1'' plate or some 1 '' aluminum .
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Pa

Site Admin

Posts: 4827

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Location: Ohio USA

Post Wed Jan 14, 2015 10:46 am

Re: question for all you machinists out there

I would go with the steel plate for its rigidness. I would also Blanchard grind the plate for equal thickness, mill the upright supports and bolt them to the plate, regrind for square all over, paying close attention to the base which seats against the mill table, and add provisions for utilizing the table T-slots for holding the fixture solid and precise. Parallels placed in the T-slots would provide precise square position to the mill table with the fixture butted up against them before clamping the fixture to the table. Design the fixture so you could use it on a variety of engines. Readouts would be a plus as well for bore locations. I am getting a bit eccentric with some of these ideas for a fixture but I figure if one is going to build a fixture why not encompass all features. One could even keyway the fixture so one obtains a perfect square seat to the mill table T-slots. One could also bore a hole for use as a zero point for dialing the fixture into the mill table and work all bores from that zero bore point. And if you plan to do only one engine or two, one can always recover their investment by selling the fixture.
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Pa

Site Admin

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Location: Ohio USA

Post Wed Jan 14, 2015 10:49 am

Re: question for all you machinists out there

woody wrote:I used a 1 inch thick aluminum plate big enough to screw the cam cover to and clamp in a machine vise.


Nothing wrong with that Woody but what do you do if the setup moves on you and you did not see that movement before you finished the bores ? It does not take much of a bump to move a piece even just a tad.
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woody

Posts: 514

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Location: Wa, USA

Post Wed Jan 14, 2015 7:43 pm

Re: question for all you machinists out there

The plate is clamped in the vise. There is not enough machining pressure to move it. If it moves, I did something really stupid. For the case half, the plate is bolted to the case and the case is clamped to the mill table. I am using a Bridgeport rather than a horizontal mill.
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h.d.ryder

Posts: 298

Joined: Sun Nov 10, 2002 1:01 am

Location: Cranbrook B.C. Canada

Post Thu Jan 15, 2015 12:18 am

Re: question for all you machinists out there

So.... How about if I get my 1'' plate and cut it out and then get it surface ground to make it precise thickness and set my cam cover on the dowels and screw it to plate.
and then I should be able to use step clamps and 1,2, 3 blocks to secure it to mill table ? I will be using a bridgeport type vert. mill. And I`m just your basic hobby machinist ,that`s why I ask so many questions... and I do appreciate all your input.
Thanks a whole bunch.
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Chris Haynes

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Location: Los Angeles, CA

Post Thu Jan 15, 2015 7:35 pm

Re: question for all you machinists out there

Why not screw the cover to the case and ream them that way? Just like it was done at the MoCo.
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h.d.ryder

Posts: 298

Joined: Sun Nov 10, 2002 1:01 am

Location: Cranbrook B.C. Canada

Post Thu Jan 15, 2015 8:00 pm

Re: question for all you machinists out there

Chris Haynes wrote:Why not screw the cover to the case and ream them that way? Just like it was done at the MoCo.



That`s a good question. But how would you bore the much larger circuit breaker bushing in the cover after it`s bolted to the case half ?
If I had the correct reamers it would be easy to do, but the reamers are not available, so, I have to set it up & bore the bushings on a mill.
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Cotten

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Location: Central Illinois, USA

Post Fri Jan 16, 2015 5:13 pm

Re: question for all you machinists out there

h.d.ryder!

Sorry to get into this late, but my priorities aren't my own any more.

Most commercial replacement bushings are so close to size that there isn't much to mill, or to correct for weld repairs and the like.
So cutting them from scratch with undersized IDs is occasionally necessary.

Even when the cases are nice, often the doweling procedure will pucker the ID, and piloted reamers and hones will still like to walk the other way. So when there hasn't been any case repairs, I had the best luck with nothing more than a common triangular machinist's scraper, just removing the pucker, and wherever inking or trial fits showed an interference. In this way, each bushing can be matched to each worn journal, and with the gear train in place, eccentricities in mesh show themselves.

When things are squirrely from welds, etc., however, I would rely on a couple of millmeisters that had mapped the chests (for OHVs and Indian Chiefs respectively), and nothing could have been smoother.
My OHV fellow went to great lengths to construct a circular fixture to match the case studs and bolts, so it could be easily clamped to the mill table. The fellow who did Chiefs for me clamped up direct. As scary as it sounds, he even decked a set of cases for me while only clamped to step-blocks, indicated off of a ground rod through the mains.
Obviously, it took great patience and care, but the results were still magnificent.

An associate just dropped off a 23"X17" chunk of aluminum billet that is inked as Kaiser .750", yet it is ~.790".
I find that curious.

....Cotten
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woody

Posts: 514

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Location: Wa, USA

Post Fri Jan 16, 2015 7:32 pm

Re: question for all you machinists out there

Cotten,
That is standard tolerance for plate. Gives you some to machine for accurate size.

I used MIC6 tooling plate for my fixture. It is cast plate already milled to reasonable tolerance for a fixture plate and is fairly inexpensive.

I will try to get a pic this weekend.
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Cotten

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Location: Central Illinois, USA

Post Fri Jan 16, 2015 8:05 pm

Re: question for all you machinists out there

Woody!

It would make a lot more sense to call it 20mm.

....Cotten
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woody

Posts: 514

Joined: Mon Apr 15, 2002 12:01 am

Location: Wa, USA

Post Sat Jan 17, 2015 7:20 am

Re: question for all you machinists out there

Probably, but then everyone would freak out because they don't want metric plate.
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