What advice would you give an inexperienced tapper. I need to drill some holes and tap them and want to make sure I do it right. I have no second chances here.

I saw a guide made by Manley that will probably do the trick. It costs $120 from Summit. I want to make sure the hole is strait. Anything else that will help. I will spend the $120 if I have to, but any suggestions will be appreciated.

Thanksin advance

Dave

dont know what you are tapping but if it fits in a drill press it would be the easyest way to drill straight ,, otherwise ,, use a drill , a steady hand, good eye, and a sharp drill bit ,, if you are really concerned ,, pratice on something else ,, remember to use cutting oil and dont break the tap off on hole <guy did that today at work> if you do you have a real mess , work the tap ,, take little bites and blow out hole often to remove metal ,, above all take your time , there are center punches that are made so they fit in a bolt hole so you get the exact center , they are not to expencive if you get made in China ones ,, besure you use correct drill size ,, your tap set should have a chart for the size according to type of metal and percent on thread depth you should have

Dave , considering the investment and the hassel ( hand drilling is a bitch ) and a few other considerations, just take it to a machine shop.
I could drill and tap an awful lot of perfect threads for a hundred and twenty bucks.
Cruz through the industral area in your town, find a machine shop with a Hot Rod parked near by and catch the guy comming out for lunch, go from there.
Note: I charge alot more for digging out a tap than I do for just drilling and tapping.

------------------
Harley
69 461 El Camino Nitrous Model, 69 Chevelle coupe
70 El Camino,71 SS Camaro
79 Corvette
Kerrville,Tx.



[This message has been edited by Harley (edited 12-08-99).]

What are you trying to tap?

------------------
Steve

If you are tapping expensive parts, take them to a machine shop. If you insist on doing the job yourself, be very careful. Use two flute taps, three flute if you must and stay away from 4 flute. An amateur will probably break a 4 flute tap especially in the smaller sizes. Use name brand taps and a good tapping compound. For aluminum use common rubbing alcohol for a cutting compound. Back the tap out out enough to break the chip for every one quarter turn you go in. BEWARE.

Harleys right especially if these are blind holes in an expensive casting. Otherwise, just keep everything straight and true (impossible with a hand drill ), don't flex the tap (they're hard/brittle) and be most careful on the first turn backwards, this is where I've broken most of my taps. I mean if it's a through hole do it, but you;re talking about a $120 fixture. What the hell are you tapping anyway????Screw ins??

[This message has been edited by Gene Chas (edited 12-08-99).]

David,
don't know what you are tapping but if you must free hand my advice is to use drill bushing and hourglass used to hold them then you can be perfectly straight.

If your going into aluminium and it's not going into a water jacket, I'd use helicoils. The threads will be stronger/last longer than in aluminium. Ive put a bunch of these into used/stripped out Al intakes, easy (follow directions) and lasts.

------------------
68 El Camino...Slow, Much Work Required
98 Z28...Fast, No Work Required
Goodfellow AFB, San Angelo, TX -- Where? That's what I said..

I agree with Harley.

Give this job to a professional. If you've never tapped and died, there's some "feel" to it that only comes with experience, and that's after youv'e got a straight, smooth, round hole of the right size in the right direction.

Find a GOOD machinist.

I am tapping the engine block at the starter mounting surface. I want to add the hole my 400 block doesn't have so I can use a 350 style starter.

Dave

Harley I do a lot of drilling and tapping and on a daily basis. It is my reccomendation to get yourself a small piece of steel about 1" thick and big enough to get a clamp on it. Now in a drill press drill a hole in one end for your tap drill size and on the other end of this piece drill a hole just large enought to let your tap pass through it. By clamping the piece onto the block where you need the hole and drill. The 1" thick block will keep your drill true enough. Good luck

Dave, the hole you are trying to do is not just drilled and tapped, it is also counter bored. Also there are location issues that need to be addressed. If you are off location even a little .010.015 you could have starter problems that will not be easly resolved.
Your statement "no second chances here" may be more correct than you think.
When you do end up at the machine shop take along the starter you want to use so the machinist can properly measure the location ( distance between holes).

------------------
Harley
69 461 El Camino Nitrous Model, 69 Chevelle coupe
70 El Camino,71 SS Camaro
79 Corvette
Kerrville,Tx.

Dave, as a final note, don;t even think about not counterboring and not using the correct knurled bolts for this app. I wondered why the starter gave out when I first got my 67. They used hardware store grade 3 bolts w.o the kurling. Grade 3. Christ they should've of used quick ties.

Essential for the starter mounting.

Dave,I would'nt do it willingly but if I had to race the next day... I would have someone with a small lathe make me up a bushing that is as long as the length of the nosepiece hole that the bolt goes into and with an outside dia. to fit TIGHT into the hole and a 5/16 dia inside dia.(if the bolt has a 3/8-16 thread). Press the bush. into the hole.(it will only be about 1/32 thick and will deform if not careful).Then bolt up the starter snug with the one existing bolt hole that you have and then with the starter drive spring removed I would position the starter so that the drive gear (in the engaged position) and the flywheel gear are meshed without too much or too little play. Centerpunch a spot using a 5/16 transfer punch,take down the starter and view your mark. It should look "aligned". If it looks right put the starter back up and repeat the gear alignment procedure and drill the 5/16 hole. Take the starter down, remove the bush,realign the starter,use the hole as a guide to both tap the hole and the drill the pilot hole. Measure the dia. of the knurled sec.of the bolt.and buy that drill,(probab. a letter or # drill) and drill a LITTLE deeper than the amount of knurl that sticks beyond the nose. Boy, only if I had to and better you than me.Use only quality stuff and use the techniqes the guys above descibed. GFL,Rob

Ok, all advice is good and well appreciated.

Here now lies the dilema. The motor is in the car. Now I know you guys are going to say "just pull it" well putting it in and setting up the tranny was a major pain in the azz. Can I do this will the motor in the car? If not, I am going to be hating life over the holidays as I try in finish this POS before I have to go back to school.

Dave

I would almost garantee you will never get the hole anywhere near close enough or straight enough, especailly with the engine in the car.

Might I ask why you want to use a different starter ?



------------------
Dean Call
Team Gold member #3
A.C.E.S. # 00235
N.C.O.A. # 4350
M.A.C.C. # 001
A smile is an inexpensive way to improve your looks almost instantly.

macc.chevelles.net (http://macc.chevelles.net)

Now that is a long story. Simply put, I have a custom application that requires this to be done. If I anticipated this problem I might have done this before the motor was assembled, but I didn't. NOw I am dealing will my mistake. I just want to get my car done so I can drive it. I wont have any time to work on it after class begins in January, so I have to finish soon.

OK, in the car, removal and tear down not optional. Let me sleep on it tonight, and I'll give you the best answer in the morning.
I am sure it can be done just let me work out the details and make some measurements.
Do you have a half inch drill and safety glasses? Also check the block for a boss in the area that needs the hole.

------------------
Harley
69 461 El Camino Nitrous Model, 69 Chevelle coupe
70 El Camino,71 SS Camaro
79 Corvette
Kerrville,Tx.

David,
I don't understand why you are drilling and tapping anything ? Unless you already have a starter that you insist on using, just go get the correct starter, or go to an auto electric shop and have them put the correct nose on yours. There are only two different flywheel diameters, and you can get the starters for both staggered or straight bolt patterns to fit either flywheel so you can save ourself a lot of work by just getting the correct part.
Just my humble opinion,

------------------
Bill Koustenis
Advanced Automotive Machine
Waldorf Md

1971 Heavy Chevy - original owner
Team Chevelle #100

Bill - If it is that simple I would love to. But as far as I know nobody makes a starter that will work. I need one that fits the 153 tooth flywheel yet uses the stagered pattern. Nobody makes one as far as I know. All stagered patterns, as far as I have found only fit the 168. I have purchased many starters and talked to many people about this.

If anyone knows of a stagered pattern 153 tooth type starter let me know where I can get it please.

Dave

Dave,
Well seeing what you're trying to acomplish Trimetal is right.Do you have access to a 350 block if so use at least a 1/2 inch thick piece of metal and make a temp and bolt to the other holes but I would go just under size and ream up on the new hole. Now some may think ream up with a drill no you must use a reamer tap and then use a bottom ream to open up for the knurl If you need any more help let us know. http://www.chevelles.com/forum/smile.gif

David , Listen to BillK and go to a auto electric shop ,, not a auto parts store, A auto electric shop deals with stuff like this all the time , your problem may be as simple as haveing them change your starter drive to correct tooth count and size , and/or changeing the nose on your starter....Have you checked with a Auto Electric shop or just auto parts stores?
If all else fails I have a idea to get your starter mounted correctly ,, first remove all your spark plugs and disconnect power to distributor , doing this will allow engine to turn over easyer ,, next if I am correct in my thinking one of the holes you already have is in correct possition? if so install starter with that one bolt and align it as best you can and tighten that bolt good ,, next <carfully> crank engine and listen and see if it cranks smoothly with no abnormal nosies , if all is well use a centering punch that is same size at your hole in starter, these punches are sold pretty cheap <around 20.00 a set> slide the punch in starter hole and mark your center and drill and counter sink the hole ,, this is a pretty easy thing to do with experiance , you may and probbly should have a shop do it as shiming the starter will most likely be part of this job and shiming a starter can be a pain in its self
------------------
John
Catapiller Mechanic
Salinas,Ca
70SS 454 Clone {in construction}

[This message has been edited by catman (edited 12-09-99).]

[This message has been edited by catman (edited 12-09-99).]

Tools Required:
1/2 Drill Motor
25/64 Jobber Drill .390
3/8 Jobber drill .375
5/16 Jobber drill .312
3/8-16 2 Flute tap
Tap Handle
Procedure:
Remove sparkplugs disable ignition system.
Mount starter useing exisiting hole ( a factory front starter support bracket may help ) attach wires.
Operate starter and check for proper alignment.
When you have starter where you want it;
Use 25/64 drill to spot block. This is the hole size in the starter. Go through starter hole and spot the block. About .060 deep.
Use 5/16 drill next. This is the tap drill size, drill as deep as you can with the starter still mounted, it will help you keep it straight.
Use 3/8 drill for counterbore. The counterbore is appox. 5/16 deep. You'll have to figure a way to gauge this depth, I would just eyeball it. It is as deep as the 5/16 drill is round.
Remove starter and finish 5/16 drill depth if nessessary. A couple of blocks I looked at had this hole just pokeing through a little.
Tap 3/8-16 to full depth. The 3/8 counterbore will help keep the tap straight.
Use a proper tap handle and apply force equally to each side of the handle.
You will be tapping cast iron with (I hope) a good quality tap. So no lube is nessessary, start your tap and go for as many threads as you can get. When you "feel" it start to load up, back tap all the way out and clean.Then go for a few more threads repete this procedure until it bottoms.
Dave, I am used to writing this stuff for machinists so if you have any questions you'll have to ask, I check this board and my E-mail at least three times a day.
This is not as difficult as it sounds, but the most important part is the "spot" as it will determine the location of all of the other operations and will make or break the whole job.

------------------
Harley
69 461 El Camino Nitrous Model, 69 Chevelle coupe
70 El Camino,71 SS Camaro
79 Corvette
Kerrville,Tx.

If you insist on spending a lot of money then
just slip the tranny back and replace the flex plate and converter (if required).
Howerver, My ZZ430 has the straight across pattern and a 153 tooth flex plate.
The engine that came out of the Elky had a 168 tooth staggered pattern starter, but that starter was brand new by 2-months and I'm too cheap to toss it and buy another one so I just swapped noses. It's a HOLE lot easier and cheaper too. http://www.chevelles.com/forum/smile.gif
------------------
Lowered '67 Elcamino
ZZ430 eng / 4L60 trans
"Canyon Carver"




[This message has been edited by Cardiac (edited 12-10-99).]

Dave,
Believe me, both starters are available. But you have to go somplace where they know what they are doing. I am not 100% certain, but I think the application is any late model (1970 and later) Powerglide equiped small block. An Auto Electric place will know what to do ! If I am at the shop in the morning, and the electric guy we use is open, I will call him and find out for sure.
Bill K

[This message has been edited by BillK (edited 12-10-99).]

Thank you Bill. I would really appreciate that. If such and item exists you would make me a vey happy man.

Dave