PDA

View Full Version : Tip on transferring a bolt-hole circle (thanks YOD)



Fasttrack
01-01-2007, 07:13 PM
A little while ago I was having some troubles making a part for my mini-bike and the topic of transerfing bolt hole circles came up. I think it was Your Old Dog who suggested using a candle to produce soot on the part and then using a piece of clear tape laid over the part to make a pattern.

Today, working on the overly-compicated plan to change a lawnmower engine into an air compressor, i had to transfer a kinda weird bolt hole pattern that i made on another part to a piece of flat plate. They weren't through holes so i couldnt use a transfer punch...while thinking what i had better do, YOD's suggestion came back to me. Instead of a candle, i used the worthless bernz-o-matic oxy/acetlyne rig with no oxygen to produce a nice, even layer of soot on the part. A bit of clear packing tape and a i had a perfect pattern with nice crisp lines. Worked like a charm. The sooty MAP gas flame was perfect for laying down a coating quickly.

Thanks YOD!


p.s. nice hat!

Forrest Addy
01-01-2007, 07:36 PM
There's several clever tricks for direct transferring threaded hole locations to a blank part.

I like transfer screws, transfer punches, etc for onesy twosy jobs. I've used soot, prussian blue, lipstick, paint, anything handy to transfer hole locations from existing parts to new parts made to fit.

I've never had a hiccup of trouble matching hole patterns until I went to measure them. As soon as I drill a measured hole pattern I know I better find a good round file to make "adjustments".

CCWKen
01-01-2007, 09:00 PM
LOL... I just came in from the barn and had to do the same thing. I was adding some 1/2" reinforcing flat to the 3-in-1 Sheet Metal Machine. The 4" flat needs to go across the upper bending die carrier. I took some 5/16" grade-8 bolts and turned a cone about 3/8" up from the threaded end. At the same time, it parted a little threaded plug/transfer punch. I made six. I then ground two flats on either side of the cone. This was so I could grab it with needle nose pliers to install/remove.

It worked great!

Tin Falcon
01-01-2007, 09:10 PM
I like transfer screws, transfer punches, etc for onesy twosy jobs.

I've never had a hiccup of trouble matching hole patterns until I went to measure them. As soon as I drill a measured hole pattern I know I better find a good round file to make "adjustments".
Forrest:
I have been wanting to add some transfer scews to my tool collection. I aggree with measured patterns . I though it was just my lack of skill in that area. I do not feel so stupid now.
Tin Falcon

Your Old Dog
01-01-2007, 10:21 PM
p.s. nice hat!

What? You mean this old thing?

http://www.raymondswan.com/dp/tinfoil%20hat.jpg
I plan on doing one up for more dress up occasions like elections, town hall meetings and such.

Glad you found the process to work for you. Just a tip, the less soot you put on the better as it will resolve a much greater degree of accuracy right on down to fingerprints. that's why I like the small birthday candles the best. If you do put more smoke on, it is possible to make a "pull" and then stick it to another piece of the same tape to make a "reverse pull" These are properly called "smoke prints" and you can do a lot with them.

JRouche
01-01-2007, 11:11 PM
I've used lipstick, anything handy to transfer hole locations from existing parts to new parts made to fit.

Hmm, ok. Secure in yer masculinity...Good...;)

I have some nail polish in the thread locker bin. I like it for setting screws that dont need as much holding power as the removable blue thread locking juice. JRouche

EDMTech
01-02-2007, 12:44 AM
A sheet of ordinary paper and a pencil work well doo. Lay the paper over the bolt circle to be transcribed and rub the pencil lead longways across the paper. Not limited to pencils either, anything that will mark the paper will do. I've even used my dirty fingers before in a pinch! :cool:

Of course, this won't give you a negative image, so if the pattern is not symmetrical it isn't going to work very well ;)

Fasttrack
01-02-2007, 02:06 AM
"I aggree with measured patterns . I though it was just my lack of skill in that area. I do not feel so stupid now. "


Same here!


YOD - thanks again for the tip... i did have quite a bit of soot on there ( :D ):

http://i108.photobucket.com/albums/n22/fasttrack237/garage%20stuff/P1010075.jpg


The real p*sser is i screwed it up. Had nothing to do with the transer - just me being a moron. It took me several hours just to get it cut, faced and all the holes drilled in it and then i realized i reversed two holes. I guess i'll go back and slot my bolt hole pattern to make up for it. Sucks when you actually get the bolt hole pattern correct but you have slot it anyway... :(

Your Old Dog
01-02-2007, 07:04 AM
If the design you're trying to copy is asymetrical you have to do the "reverse pull", that is, once you lift the tape off with the soot on it, you have to put a another piece of tape on the first tape and then seperate them to get a reverse image. Obviously it helps to fold over one end of each piece of tape when you make the sandwhich so you can pull them apart! When you do "reverse pulls" it helps to have a little more soot on then is required for on one pull.

The pull you have looks good to me as I can even see some machine marks in it.

Swarf&Sparks
01-02-2007, 09:15 AM
I think I'm missing something here.
I've used engineer's blue, grease, and even lipstick to transfer prints for something like a gasket. Gaskets are easy, locate your wad punch and clout it.

Smoke prints, wotever. Once you've transferred the print to the workpiece, you still have to locate hole centres or other datum for machining.
Any and all advice appreciated.
Rgds, Lin

Your Old Dog
01-02-2007, 09:41 AM
I think I'm missing something here.
I've used engineer's blue, grease, and even lipstick to transfer prints for something like a gasket. Gaskets are easy, locate your wad punch and clout it.

Smoke prints, wotever. Once you've transferred the print to the workpiece, you still have to locate hole centres or other datum for machining.
Any and all advice appreciated.
Rgds, Lin

Essentially you are just putting a copy of the "blue print" on the work you want to work on. No, it is not as accurate as DRO placement but many projects don't need that type of accuracy and it would in some cases take forever to use a DRO on weird projects. Setting a copy of the lifesize blueprint on the raw metal is simpler methode where accruacy is not paramont. Given a wide enough piece of tape (side by side) I can be done drilling the holes for head on a lawn mower engine before you've drilled the first hole.

I have a belt buckle I made using a smoke print of a silver dollar and chisled out by hand. It's pretty close!

Swarf&Sparks
01-02-2007, 10:23 AM
Thanks YOD, pretty much my thoughts. Figured I'd ask on the basis of "there's no such thing as a stupid question". (unless you ask it 2 or 3 times)

Fasttrack
01-02-2007, 02:11 PM
Thanks YOD, pretty much my thoughts. Figured I'd ask on the basis of "there's no such thing as a stupid question". (unless you ask it 2 or 3 times)


lmao - thats one of my pet peaves; the people who keep asking you the same thing over and over again. My parents are getting to be that way...its sort of endearing with them since they are getting older and they dont mind laughing about it :D



YOD- the part was symmetrical but it had to be on one specific side of this plate. The plate bolts on to the cylinder of a extremely beat up old tecumseh engine and the block then bolts to that with another plate on top. The block holds some springs and ball bearings to make little check valves (my overly-complicated compressor design) but because of the way that center block is made and the fact that the head bolt hole circle isnt centered on the plate its side specific. I put it on the wrong side... dang it :)


http://i108.photobucket.com/albums/n22/fasttrack237/garage%20stuff/P1010076.jpg

I guess i'll probably weld in the mistakes and remachine them <shudder>