Honda CB750 Sandcast
The Restoration Shop => Engine - Cosmetic Only => Topic started by: Steve Swan on March 27, 2011, 11:09:24 am
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PROGRESS REPORT
As you recall there was talk some time back about converting late thick lip alternator covers to the early thin lip. (As we know, the thin lip was used until around engine vin 11xx)
Marty Kitner loaned his thin lip cover to Mark McGrew www.m3racing.com (http://www.m3racing.com) as an example for Mark to determine what would be involved with converting the later cover to an early cover.
Mark has the machine program pretty much written. Essentially all that awaits to begin the project is setup on the first cover and inspect the results.
How many of you guys want your cover converted ?
Respond here so we can get an idea.
Once we have an idea of the number, then we can go to Mark and get a price. I am told the conversion will not be inexpensive.
I have no idea of cost for conversion. Getting a cover converted by Mark will probably be an "either you're in or you're out" one time opportunity.
For those who may not have a cover, if i recall correctly, i believe Mark said he had some spare covers, otherwise it might be good if you can supply a core for the conversion.
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Steve:
Count me in for one (1) cover, I'll supply my own core. Marty K.
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I'm in for 1 cover and i'll have a core.
We'll track the number of interested parties on this thread.
Thanks again Marty, for loaning your cover to Mark for this project !
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I'll have 2 and I'll supply the cores KP
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I want 2 depending on the price and can supply the cores.
I am assuming he will be surface milling these on a CNC based on the comment "machine program pretty much written". Probably be a good idea to find Mark a junk cover for a setup part and get a first article inspection to be sure Mark gets it right. Sorry, did not read Steve's posting thoroughly. I own a machine shop and know that surface milling requires good core, good geometry, good setup, and good G-code. Since these are castings, there will probably be some variation in them and the profiled surface may not blend exactly to the original core. I have not measured any to see how much variation may exist. Could possibly require a little hand blending.
Thanks Marty for having the faith in McGrew to make this happen. There's no way in hell I would send McGrew or anybody else for that matter either of my 2 originals for such an endeavor.
Keith
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kmb69:
Some times faith is what the world needs. Enjoy and have a nice day. Marty K.
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Mark+Wayne, Thanx for the heads up/happy to say my covers is perfect! Tim-Nmbr 12
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I'm interested in 1 or 2 but, if possible, i would know the cost with and without the replacement of a mine cover.
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When we learn more about cost, core availability, etc; we will share what we learn.
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Mark McGrew here, let me... let all know at same time. I am not sure that machining these covers can be done to the exact standard that you members want. This is a very tricky job, but it might look or seem a simple task. My son when he looked at it, said, why don"t you just hand grind these things as there will be some hand work involved at end of machining anyway? He might be right. Also, no one yet has told me what they will pay for these covers and as this is a limited market what will I be able to sell?
It works like this, I will have hours and hours of set up time and then run time to test (wreck) a few beat up covers I have here, but to get a nice finished cover, customers need to send me nice covers to start with... as you don't want to have a thin lip profile on a cover that has deep scratches in it or cannot be polished back to OEM finish...correct?
And now if I do one cover the cost would be 1000 dollars, 4-5 prob 350-400, 10-15 200-250.00..so you can see that there is an "economy of scale" at work here.
anyone with interest, better form a line... so I can see if this is even worth it.
Mark
M3 Racing USA
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Thanks, Mark. Appreciate your post !
All who are interested in having a cover conversion, let's "sign up" so we can get an idea of how many conversions there could be !
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I would do one, maybe two.
Mark
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Mark M,
At $200 to $250 I'm good for 2 guaranteed. So fellas,we need at least 10 starters to make this work out at a reasonable price. :P
I've got good covers so no issue for me with those
PS. If I need to get 3 covers then I'll get a third but really only need 2 "guaranteed" KP
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Mark Mc:
I'll up my anti by one (1) for a total of two (2). I will supply the cores. Marty K.
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Good start, let's find some more buyers...
Mark @ M3 Racing
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Fellas
We need to get this project off the ground. Mark is saying he needs 10 to get this price to around $200
So far we have
Steve x 1
Mark x 1 Maybe 2
Marty x 2
Riccardo x 1 Maybe 2
KP x 2
Keith Possible x 2
So we have 7 for sure and possibles at 4
Can we just get everybody to confirm.
Mark M, some have asked for cost of a cover from your stock. Got an estimate
Thanks guys
KP
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Bump this again Any more takers KP
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Who all will commit to purchasing a thin lipped alternator cover ?
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I will for sure do one. If I can find another decent cover I would do two.
Mark
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Reading (between the lines of) Mark McGrew's post from the past, he expresses concern milling/machining will not be able to make an exact duplicate of the thin lip's contours seen on early covers. His son said, "Why don"t you just hand grind these things as there will be some hand work involved at end of machining anyway?"
What Mark's son is suggesting (my interpretation of his comment) is: Instead of machining off the material to make a thick lip cover a thin lip, hand grind the thick lip to a thin lip.
In other words, after a late cover is machined to have a thin lip, hand work will still be required to give the original appearance of a thin lip.
Machining the thin lip to the exact appearance of original may likely not be possible, because the cutting tool will not have the contour of the radius/radii of the thin lip to exactly produce original thin lip appearance.
In my limited first hand machining knowledge/experience, the ability to re-produce the exact contour of the lip, the contour is created by the shape of the cutting tool available for making the cuts. The ability to make the lip contour exactly like original is limited by the shape of the cutting tool available to be used to make the cut. If I'm reading things right, Keith Byers expresses a similar concern/consideration in his post.
My E254 engine did not have an early cover. I removed the material by hand, but only on the upper portion in the visible 10 o'clock area. I considered removing the material on the rest of the cover's periphery, but did not, in hopes I might find a thin lip cover........ some day. These covers are rare, as we all know. Probably, at some future date, as time permits, I'll wind up removing my cover to remove by hand the material of the thick lip to make it look like a thin lip.
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As I say, I'm up for 2 guaranteed KP
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Instead of machining off the material to make a thick lip cover a thin lip, hand grind the thick lip to a thin lip.
In other words, after a late cover is machined to have a thin lip, hand work will still be required to give the original appearance of a thin lip.
I agree that machining it won't be perfect and that hand work will have to be done. But, I think that machining it close is not only going to save a lot of work it's going to make a better product. Just my opinion.
Mark
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Agreed ! I wrote what i wrote, because i'm not sure what other interested party's expecations of the machined product would/could be. Would be good to hear from Mark McGrew to know the status of the project. Sounds like we may still have at least 7 "for sures" and maybe another 4 "possibles."
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Sorry for resurrecting such an old thread, but McGrew came up in a conversation tonight and it made me wonder if Marty ever got his cover back?????
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Good resurrection.
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I agree. I'm still in if this project is a go. Any updates?
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Hi all:
Yes Mark McGrew is still in possession of my thin lipped cover. I am (along with others) hoping the modified covers will be made available. The bike the cover was removed from is next in line to be restored with-in six to eight months from now. I like to restore the engine first as it helps keep me motivated to finish the smaller tedious items (frame, wheels, etc. Marty K.
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I may be sticking my neck way out here but a couple of weeks ago, I ordered a high end 5-axis machining center for my personal shop. Delivery is expected in 4-5 months as it was special ordered with 5-axis simultaneous capability. Many so called "5-axis machines" are really 4-axis simultaneous with 5th axis positioning. This one is the real deal and I am kinda excited about it.
Anyway, in the event that McGrew doesn't come through in a timely manner, and I know it's only been a little over a year now, this could be one of the first projects that we try to make happen.
Keith
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I'm in for one.
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Keith:
If you decide to do the project good on you. I would guess from your earlier posting you already have several thin lipped covers to use as a pattern. I would be good for two (2) covers and if you need cores i can supply them also. Marty K.
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Mmmmmmmmmmmmmmm! Yes please 2 for me ;D
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I ordered a high end 5-axis machining center for my personal shop.
:o Must be a nice shop! I'm still on board. Put me down for two. I've got one and I'll find another cover.
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Keith:
If you decide to do the project good on you. I would guess from your earlier posting you already have several thin lipped covers to use as a pattern. I would be good for two (2) covers and if you need cores i can supply them also. Marty K.
Marty, I do have several thin lipped covers to use as a pattern. This is not a gotta make money deal for me and I don't need a certain number of commitments. I will be doing some for myself and will post results for review. Machine is scheduled to be delivered early April.
Keith
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Mmmmmmmmmmmmmmm! Yes please 2 for me ;D
Forgot to mention I have covers also
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Keith: I asked to have my thin lipped alternator cover returned, of which i received today. Your up next if you decide to do some of the modified covers. Marty K.
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I wondering while ya'll are getting the type I covers made, what is the chance of have some type II covers made for the rest of the sandcast serial numbers?
I'd like to know if there is a need/interest (or maybe a larger need) for the type II covers to be reproduced/altered from current cover stock.????????
Anyone need the type II covers for their sandcast? I do!
Conrad