Cylinder Boring & Honing Survey

[GPYamaha]

Hi Everyone,
I own a small machine shop that produces prototypes for products. My machines are also suited for boring cylinders. I have several of my own cylinders that I plane to bore in the coming weeks. A few people have suggested that I offer boring and honing as a service; however, I’m not sure this service is in demand. I would like to hear from members their opinion on the need for this service.

Thanks

 

[grouchie77]

There seems to be demand for it, but I can't say how much. What type of machine? I program and run vertical CNC mills at my work, and could bore my own cylinders if needed, but most people don't have that luxury like we do.

 

[GPYamaha]

I have a 4-Axis CNC Vertical Machining Center. I can probe cylinder centers and program single or multi-cylinder centers. This would be an improvement over typical MC boring machines that require moving and centering each cylinder. I also have a CNC bed mill that I don’t use that much. The bed mill would be good for controlled honing.

 

[ScottK]

From what I found on a quick search $60-120. per cylinder

 

[willis]

Locally they charge $100 per hole.

 

[Sparkyduc]

Locally they charge $100 per hole.

Locally they charge $100 per hole.

At Sehorn Yamaha in Shawnee Oklahoma, they do it for $50 a hole. I think that’s a bargain.

 

[gggGary]

My local engine guy has dunno, 6? sets of my XS650 jugs to bore for 700cc pistons. I think he's had them a year and half now. Stopped in to visit last week "soon" LOL

 

[Ratranger]

At Sehorn Yamaha in Shawnee Oklahoma, they do it for $50 a hole. I think that’s a bargain.

Wedman in OKC charges $75 a hole. I'd spend the difference on time and gas from Yukon. Outside of wedman no one in OKC does anything smaller than harley stuff that I know of.

I recently bought a cyclecyl boremaster off marketplace so I can even avoid that drive.

 

[AUTOMAN]

You have to mess a few up to know how to do it, correctly.
(On existing center of bore or re-qualify off base)
(On specified center, off base requalify)
(Take iron out to aluminum)

on and on

Boring on existing center, then hone to specific micro-finish is what most folks want.
Do you have a rigid hone set? A must. Profilometer? A must.

cliff

 

[GPYamaha]

I have 10 or 12 of my own cylinders I have to do and none are single cylinder. At this time I’m trying to gather information to determine if it is worth offering this service to others or just do my own. MC cylinders are east to ship. Machines, 4-Axis CNC Vertical Machining Center, can locate center within .0001” - .0002”, Sunnen Hone, Mitutoto Profilometer. I don’t like indexing each cylinder to the boring head as with typical MC boring machines (cyclecyl boremaster). For multi cylinders, I prefer mounting the cylinder once and locating all cylinder centers. I can then measure bore and adjust if necessary without re-indexing all the cylinders again.

 

[RC4MAN]

Local auto machine shop I used to use has quit boring

 

[AUTOMAN]

I have 10 or 12 of my own cylinders I have to do and none are single cylinder. At this time I’m trying to gather information to determine if it is worth offering this service to others or just do my own. MC cylinders are east to ship. Machines, 4-Axis CNC Vertical Machining Center, can locate center within .0001” - .0002”, Sunnen Hone, Mitutoto Profilometer. I don’t like indexing each cylinder to the boring head as with typical MC boring machines (cyclecyl boremaster). For multi cylinders, I prefer mounting the cylinder once and locating all cylinder centers. I can then measure bore and adjust if necessary without re-indexing all the cylinders again.

and if bored off center the last time, you plan on following same mistake?

 

[Ratranger]

I have 10 or 12 of my own cylinders I have to do and none are single cylinder. At this time I’m trying to gather information to determine if it is worth offering this service to others or just do my own. MC cylinders are east to ship. Machines, 4-Axis CNC Vertical Machining Center, can locate center within .0001” - .0002”, Sunnen Hone, Mitutoto Profilometer. I don’t like indexing each cylinder to the boring head as with typical MC boring machines (cyclecyl boremaster). For multi cylinders, I prefer mounting the cylinder once and locating all cylinder centers. I can then measure bore and adjust if necessary without re-indexing all the cylinders again.

I know the standard boring bars, boremaster, kwik way, rottler etc. take more setup than a CNC. I run CNC at work, probing a bore in is fast and easy. I have a manual mill at home but it is old/worn enough to not be accurate enough for boring a cylinder. The nice automotive boring machines don't go small enough for a lot of bikes. And newer stuff doesn't have a liner requiring specialty shops like millennium tech to bore or repair.

It used to be just about every service department could bore a cylinder. Not anymore, the demand is lower and it's becoming a niche market. There are a lotof places advertising on ebay and others that they bore cylinders. I think you could make money at it, but not replace your day job money.

 

[GPYamaha]

and if bored off center the last time, you plan on following same mistake?

Inspection before boring, just like what is done on car engines to see if there was any core shift during casting

 

[RC4MAN]

Just like This Old House, Measure Twice, Cut Once
Wouldn't mind picking up an old Kwik Way or other but every time I see one come up they want a small fortune for it regardless of age or condition.
Bridgeport type mill doesn't have enough stroke to do the typical bore, though I did do the Tecumseh mower engine for my dad many years ago using one with a right angle head and using the table drive. Worked but Not something I'd like to repeat.

 

[GPYamaha]

I know the standard boring bars, boremaster, kwik way, rottler etc. take more setup than a CNC. I run CNC at work, probing a bore in is fast and easy. I have a manual mill at home but it is old/worn enough to not be accurate enough for boring a cylinder. The nice automotive boring machines don't go small enough for a lot of bikes. And newer stuff doesn't have a liner requiring specialty shops like millennium tech to bore or repair.

It used to be just about every service department could bore a cylinder. Not anymore, the demand is lower and it's becoming a niche market. There are a lotof places advertising on ebay and others that they bore cylinders. I think you could make money at it, but not replace your day job money.

I agree, may be more a hobby than a money maker. Probably OK if customer was close and didn’t have to ship cylinders. Just the amount of time to box and ship back to customer would make it more expensive without providing any benefit to the customer.

 

[grouchie77]

The best way to bore the cylinders i would think is to tram the head in, then probe 2 diagonally-opposed dowels. Call that the center of the block, and then you can move to where the bore should be, not necessarily where it is.

I think the center-to-center of the 650 is 120mm. So I'd move X-60.00mm and X+60.00mm and bore in those locations.

 

[Ratranger]

The best way to bore the cylinders i would think is to tram the head in, then probe 2 diagonally-opposed dowels. Call that the center of the block, and then you can move to where the bore should be, not necessarily where it is.

I think the center-to-center of the 650 is 125mm. So I'd move X-62.50mm and X+62.50mm and bore in those locations.

That would probably work on a lot of engines, but some are offset from the stud centerline. One example I know is the honda xr200. It's common when going big on them to shift the bore to centerline of the studs to get more room for the bigger sleeve.

 

[AUTOMAN]

I would know the bore spacing and deck height.
Check parallelism base to deck.
Find reference datum for x/y on jug.
Find datums for machining, requalify.
Establish master cylinder position. Requalify master datum.
Bore.

 

[gggGary]

I'm not a smart man.
Center on the bore at the top of the cylinder where there hasn't been any wear?
I'd guess 95% of bores are done that way?
A bigger issue is fixturing? If you want it to be round once installed tightening the cylinder to a fixture sandwiched in a "hat" jig using the cylinder stud holes tightened to spec might make a difference. That'll blow up the per hole cost unless you are specializing in say XS650 cylinders where you have dedicated fixtures. I've seen an XS650 rebore that went wrong with bad scuffing, interference at the 4 studs. Our best guess was; tightening (overtightening?) the studs changed the shape of the bore. A long story but a shop that did lots of V8's did the bore job.
Another "gotcha" on XS650's is the long unsupported liner that extends down from the cylinder casting. My guy pisses n moans about doing 700cc bores. I think he can SEE the liner distorting as he bores cuz the liner gets so thin, unless he takes quite shallow cuts. That adds time to the process.