How much should this cost? And how much time should it take?

[Threadkiller]

Hey all I have a pair of rotors where I need the hub bore opened up from 67.8mm to 70.6mm. I was originally going to do it myself by making a jig using old rotors and bolting the rotor down and using a 70mm hole saw or possibly a cylinder hone. Everyone I talked to said they wouldnt mess with it and just to bring it to a machine shop. I was hesitant at first because I like doing things myself but after thinking about it for a while I said screw it that would be the better way. I called 12 local machine shops today, 10 of which said they didnt want to do it. One of them said they would do it but they charge a $75 flat fee plus whatever time it takes and said he would need them for an entire day. The other said he would have to set it up on the machine and see how long it takes him but he couldnt get me a price until he does so and also said it would "probably be time consuming". So basically the guy has me over a barrel at that point and could charge me whatever he wants once he has the rotor on the machine.

I was all willing to spend $50 (people that have gotten it done on my forums have stated 20-50 bucks) on it but all of these well equipped shops are making a big deal out of it by flat out denying it or scaring me into thinking its some kind of big deal. I understand precision costs money but theres a point where it just seems like a rip off to me. So I figured I would post on here to get some opinions of people that actually do this for a living or mess around with it as a hobby. Does it really take "a long time" to put the rotor in a machine and dial it in and machine out 3mm?

At this point im back to doing it myself in a drill press bolted to my jig using either a hole saw or cylinder hone.

 

[koditten]

I hear ya. I know there are several members here that have their won lathe. Hold on for a bit, they will find this post.

KO

 

[koditten]

By the way, where are you at? You might get a bit more response if we knew you general area.

KO

 

[Nelkcots]

What part of the country are you in? Something like that sounds to me like a side job or something for a garage machinist... I know I have done favors for people similar to this. My shop would not even consider it, however I would do stuff like this on the side / after hours... I would think 50-75 bucks for a side job for a machinist if you could find someone.

 

[rsanter]

exactly what are you trying to do?
Im think you are trying to fit the rotors from one car or make onto another car or make/model.
have you though about having the axle or hub turned down to fit the rotors so when you have to replace them in the furture you wont have to modify a set of rotors again

and yes, post where you are so perhaps a local member could help you

bob

 

[zkling]

Shoot your are only talking ~0.050" cut on the radius (I don't work in metric)

I would do them on my mill. 30 minutes tops. Probably charge $40 for both (my general side work shop rate is $80 per working hour) but that is without seeing the rotors.

Bolt to mill, sweep with indicator to center, use boring head to open up. Real simple job. I wouldn't even bother with the lathe. Plus you would probably need a good size lathe to swing them.

 

[koditten]

Shoot your are only talking ~0.050" cut on the radius (I don't work in metric)

I would do them on my mill. 30 minutes tops. Probably charge $40 for both (my general side work shop rate is $80 per working hour) but that is without seeing the rotors.

Bolt to mill, sweep with indicator to center, use boring head to open up. Real simple job. I wouldn't even bother with the lathe. Plus you would probably need a good size lathe to swing them.

I'm not even a michinist, this is exactly how I imagined it.

 

[Threadkiller]

By the way, where are you at? You might get a bit more response if we knew you general area.

KO

I am in Dutchess county NY

What part of the country are you in? Something like that sounds to me like a side job or something for a garage machinist... I know I have done favors for people similar to this. My shop would not even consider it, however I would do stuff like this on the side / after hours... I would think 50-75 bucks for a side job for a machinist if you could find someone.

I am in NY, I am currently looking for a hobby machinist or the like to try and get this done.

exactly what are you trying to do?
Im think you are trying to fit the rotors from one car or make onto another car or make/model.
have you though about having the axle or hub turned down to fit the rotors so when you have to replace them in the furture you wont have to modify a set of rotors again

and yes, post where you are so perhaps a local member could help you

bob

I thought about that, I dont know if there is enough material on the hub to get them turned down. I am doing a brake conversion on my 2000 Camaro which requires 2010 Camaro rotors of which the hub bores are 67.8mm. Another reason I scrapped the idea about getting the hubs turned down is because I thought it would be easy and relatively cheap to have the rotors machined

Shoot your are only talking ~0.050" cut on the radius (I don't work in metric)

I would do them on my mill. 30 minutes tops. Probably charge $40 for both (my general side work shop rate is $80 per working hour) but that is without seeing the rotors.

Bolt to mill, sweep with indicator to center, use boring head to open up. Real simple job. I wouldn't even bother with the lathe. Plus you would probably need a good size lathe to swing them.

Damn how come none of you guys are local? Thats what I expected to be charged anywhere from 50-100 bucks and I was fine with that. None of this "time consuming" BS. I dont know if these places are just trying to get one over on people or what.

 

[Threadkiller]

rsanter, heres a picture of the hub. I dont know if cutting it down 1.5mm on either side is an option. What do you think? I am far from an expert

 

[isaac338]

I am in Dutchess county NY



I am in NY, I am currently looking for a hobby machinist or the like to try and get this done.



I thought about that, I dont know if there is enough material on the hub to get them turned down. I am doing a brake conversion on my 2000 Camaro which requires 2010 Camaro rotors of which the hub bores are 67.8mm. Another reason I scrapped the idea about getting the hubs turned down is because I thought it would be easy and relatively cheap to have the rotors machined



Damn how come none of you guys are local? Thats what I expected to be charged anywhere from 50-100 bucks and I was fine with that. None of this "time consuming" BS. I dont know if these places are just trying to get one over on people or what.

I think these shops over-quote this **** because they don't want it. They make more money doing repair work and custom stuff for their regular customers than they'll ever make boring some rotors for a guy off the street, and the guy off the street is gonna come pounding on the counter when something doesn't work and he thinks it's the shop's fault.

Not saying that's what you'd do, but I bet that's what they're thinking.

 

[zkling]

I think these shops over-quote this **** because they don't want it. They make more money doing repair work and custom stuff for their regular customers than they'll ever make boring some rotors for a guy off the street, and the guy off the street is gonna come pounding on the counter when something doesn't work and he thinks it's the shop's fault.

Not saying that's what you'd do, but I bet that's what they're thinking.

Exactly. Usually full time shops keep busy with their regular customer. They know their setup and have been doing them for a long time. They are not trying rip you off so to say, just following their protocol. It takes time and effort to take a jig off of a machine and put your goofy one off part on. Plus they have to add you to the computer system. Make a drawing of the part, and so on and so forth. 99% of legit shops will not accept dimensions on napkins.

Hence I love the little jobs like yours. It helped me pay for college and keeps me busy in my spare time. I primarily use manual machines and keep my mill table cleared off. I will type up a real quick document on the computer for you to verify the dimensions and accept your cash. That is it, quick and simple. No drawings or other paperwork needed. However I am very careful of which jobs I accept. I have folks sign a paper if they give me a dimension. That why I can say... "Look I made it to your dimension" it is not my fault that it doesn't work.

There is a lot that goes on in a regular full time shop that most folks don't understand.

 

[rsanter]

rsanter, heres a picture of the hub. I dont know if cutting it down 1.5mm on either side is an option. What do you think? I am far from an expert

By my eye it looks like you got lots of meat there for as little as you want to remove. You could measure the thickness to see what percent of material you will be removing.

Bob

 

[racingtadpole]

Looks like you have plenty of material on the hub. I'd be inclined to machine the hub instead of the rotors. You'll only have to do the machining once, as opposed to having to do this everytime you need to replace a rotor.

Not that it helps you but...
If I took this to a shop here it would come at minimum $80 an hour, and it would most likely have a 3-4 week turn around. Its just the cost of doing business for a small bespoke job like this.

 

[zkling]

racingtadpole makes a good point if you want to continue to use off the shelf parts for your conversion it would probably make more sense to turn down the hubs. It would be more expensive initially to machine, but would be a one time cost compared to boring each set of new rotors.

 

[barlow]

I just did a disc brake conversion on a friends 73 f240 4x4( closed knuckle dana 44). I turned his hubs to fit the rotors. Done, he'll never need any further machining when the rotors need replacing.

 

[pepi]

I think I would use a die grinder with a carbide bit, we can port heads with the things. The best suggestion would be to knock out the lug studs of the stock rotor.

Place the rotors face to face draw it down with a couple of lugs ......... instant pattern for the hole size, you might need to dress it up a slight bit but it would be easily roughed in and close.

Also note how the stock one fits up to the axel boss, it will not be a tight fit bit of slop, for removal.

 

[Charles (in GA)]

The question as to whether to cut the hubs down, or open the rotors up, depends on the wheels and whether they are hub centric, or lug centric. If you are using the original wheels, I would open up the rotors and leave the hubs alone, that way, you are assured the wheels will continue to fit the same as before.

Charles

 

[larry_g]

Liability plays a bit here in a for profit shop. If the modified rotor fails down the line and a lawsuit follows the shop does not want to put itself in harms way. Or if they muff the job will you expect them to buy you a new rotor and then attempt the modification again, or will you provide another rotor and let them try again?

As a machinist I would expect you to give me a print giving me the tolerances you require. Not only the tolerance on the bore diameter but a tolerance on concentricity of the bore with the rest of the rotor. You must give me enough information to make the part plus enough detail to prove that I have done what your print asked for, not necessarily what you wanted.

As a friend with some machine tools we could spend some time discussing what you need and spend some time fitting the project together. Its not a difficult job to accomplish but it could be screwed up pretty easily and your rotor end up running an elliptical path around the spindle and very hard to get that rotating assembly balanced.

lg
no neat sig line

 

[Rentawrench]

How are you moving the caliper braket ? Most place DONT want the Liabity of working on brakes .

Donot cut the hubs wheelbearings go soon enough ,easier the cut rotor.

This going to be a track car ?

What do you think this upgrade will do ? It looks like you have the Alum duel piston caliper.

 

[bsaint]

Lets not get into why he wants it done. Just let him do what he wants.

I once tried to get welding shops to repair a motorcycle frame. No one would weld it. Not even with cash in hand.

 

[Threadkiller]

I thought about turning down the hubs and even though the wheels are lug centric, the hub helps take the load off of the studs and I dont want to have problems in the future if a wheel bearing goes, plus who knows if itll cause vibrations due to the wheel not sitting on anything.

I thank you for all the replies fellas.

I do have a dual piston caliper on there now, but I will be changing over to a 4 piston brembo caliper from a CTS-V. This isnt a race car its just my weekend fun car, however it might see some autocross.

Its just so frustrating. I found a guy yesterday (friend of a friend type deal) and I told him what I wanted and he said "sure no problem, its an easy job" and hes only charging me $60. Thats what I expected to happen from the very beginning. I understand why some shops do not want to do it but to basically get turned down by 12 shops, that I did not expect.

 

[Murphy4570]

Be happy that you have 12 machine shops you can at least call. Round here there isn't diddly squat for machine shops.

 

[astroracer]

This is pretty easy guys.... Take the hub to brake shop and have them turn the O.D. down to what you need... They can do it in 5 minutes on a brake lathe... I made a set of hubs out of worn out B body disc brake rotors. cut the rotor portion off and had a brake shop turn down the OD to clean it up and get it under six inches to clear the Corvette rotors.
Here is a few pics from a year or so ago.
Used the trusty sawzall to remove the rotor from the hub.

All cut down and ready for the lathe. These need to be reduced in diameter to 6" so they will fit in the Corvette front rotors. They will be shortened up quite a bit also.

Back from the brake shop and ready for blasting.

Mocked up on the spindle.

Mark

 

[Threadkiller]

I think i decided that I dont want to mess with getting the hubs turned down to fit. Even though the wheels are lug centric the hub does provide an extra support for the wheel to take stress off the studs. Im most likely overly paranoid but I feel like eventually something would break, even though I have longer and stronger ARP studs