Author Topic: dislexia oops, oops and oops again!  (Read 7111 times)

Offline DavidF

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dislexia oops, oops and oops again!
« on: February 18, 2013, 06:52:50 PM »
    Not a good day in the shop thats for sure. Im working on making a small jig that will mount to the T slot on my mill for drilling connecting rods. The idea is to have a tool that I can use to drill the 4-40 rod bolts into the rod by hand then mount it to the table and drill and ream the rod journal and wrist pin. I have to make a good number of rods so I figured that a jig was in order. So today I was working on the steel drill and tap guides for the rod bolts and things didnt go well at all. First off I mis read my dro because when I wrote the dimension on a piece of paper I wrote it as 2.125 the funny thing is the dimension was actually .225 (little math error) and when I set it up to drill I did it at .2125  :slap: Ok theres on wild mix up that Im surprised im telling you...  Then I decided to put lay out lines on the second part so I could visually see things were in the mark. Things were going good, center drilled both holes, drilled thru the first hole, started drilling thru the second hole and "CRUNCH"  :censored: :censored: :censored: Ok no big deal there is enough bit sticking out that removal was easy. so I re touched it with the center drill and figured I would drill tru a bit smaller then open up the hole "CRUNCH"  :censored: :Mad: :censored: :cussing: are you kidding me!!!  Ok removed that piece of drill bit re touched with center drill and re sharpened broken drill bit, spead up mill and had at her again...I made it thru, but the holes are off about .005" and I would like to be closer than that by far.  Any suggestins on drilling small straight holes within .0005"  Im A bit aggrivated and going to take a break until tomorrow..
« Last Edit: February 18, 2013, 07:14:48 PM by DavidF »

Offline DaveH

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Re: dislexia oops, oops and oops again!
« Reply #1 on: February 18, 2013, 08:59:59 PM »
David,
Sometimes it is best to center drill then go through with the drill without moving the workpiece. Also the drill needs to be correctly and accurately ground to achieve a straight hole.
 :cheers:
DaveH

Offline DavidF

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Re: dislexia oops, oops and oops again!
« Reply #2 on: February 18, 2013, 09:46:44 PM »
DaveH,  yes probably not best to move around from center drilling the drilling.. I'm going thru the things I did today in my head and rethinking the process, I don't think me moving the x,y axis had anything to do with it. I only moved the x axis and I'm off on the y axis equally on both holes. I did however have to lower the knee to fit the drill chuck and drill bit after I indicated the part using a collet.  My mill is pretty clunky so I'm thinking this is where the error is...
  I guess to fix it I could use and end mill to punch the holes oversized then make some drill bushings from drill rod on the lathe to fix the problem. Probably a good idea?
  How do you guys make your connecting rods for your engines, from step 1...?  Maybe I'm going about things the entirely wrong way...

Offline swilliams

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Re: dislexia oops, oops and oops again!
« Reply #3 on: February 18, 2013, 10:43:01 PM »
Hi Dave
Maybe you need to tighten up some of the gib adjustments on your mill? Things can move around quite a bit when the knee and cross slide gibs are loose.  If you have a lock on the knee using that could help.

Just a thought
Steve

Offline DavidF

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Re: dislexia oops, oops and oops again!
« Reply #4 on: February 18, 2013, 11:05:44 PM »
Gibs are pretty snug on x y,  knee is a bit loose but I all ways lock it up. I'm thinking it would be a good idea to do some work to the mill and also go thru my drill chucks.  I know I do have an issue with the spindle run out that I have been trying to avoid getting into for years. Anyone ever re turn/grind  the R 8 taper in thier spindle?   Going to search the web on this one....

Offline DavidF

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Re: dislexia oops, oops and oops again!
« Reply #5 on: February 19, 2013, 05:45:24 PM »
SAVED  Punched out with an end mill, drilled and reamed then made a bushine to press fit in out of drill rod. Looks like im a little under .001 so I can deal with that.   :cheers:

Offline swilliams

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Re: dislexia oops, oops and oops again!
« Reply #6 on: February 19, 2013, 11:46:22 PM »
Nice save Dave. Glad it worked out

Steve

Offline DavidF

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Re: dislexia oops, oops and oops again!
« Reply #7 on: February 20, 2013, 12:04:39 AM »
Thanks Steve.  Hopefully ill have more good days ahead. Once I get this rod jig sorted I will be starting my build thread, first scratch build steam engine...

Offline Mosey

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Re: dislexia oops, oops and oops again!
« Reply #8 on: February 20, 2013, 01:16:41 PM »
Yesterday, I spent 8 hours making 2 tiny brass exhaust flanges and soldering them onto the headers. Dropped one on the floor while soldering, it disappeared, and after crawling on the floor, looking under the benches, with a flashlight, sweeping a couple of times, I give up.
Today, I make another, better one.
Mosey

Offline DavidF

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Re: dislexia oops, oops and oops again!
« Reply #9 on: February 20, 2013, 04:12:54 PM »
Yesterday, I spent 8 hours making 2 tiny brass exhaust flanges and soldering them onto the headers. Dropped one on the floor while soldering, it disappeared, and after crawling on the floor, looking under the benches, with a flashlight, sweeping a couple of times, I give up.
Today, I make another, better one.
Mosey

  Of course you know you will find it once you make another...its that murphy fellow.... :hammerbash:

Offline Mosey

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Re: dislexia oops, oops and oops again!
« Reply #10 on: February 20, 2013, 05:02:59 PM »
Well, I got down on the shop floor where grown men fear to tread, under the benches, with a bigger flashlight. Found a die I've been missing for a few years. Lots of mouse shit. Poked my fingers in the hollow backs of the bench legs, and...Holy mackeral, captain marvel! I found it!   :zap: :zap:

Offline mklotz

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Re: dislexia oops, oops and oops again!
« Reply #11 on: February 20, 2013, 05:21:13 PM »
Hopefully those hollow legs are now duct-taped over or filled with electrician's putty.

I've often been tempted to buy one of those monster retrieval magnets (the kind used to lift sunken outboard motors) and mount it on the floor under the bench.  Wouldn't help with the non-ferrous parts, of course, but it sure would localize the ferrous droppings.
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Offline DavidF

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Re: dislexia oops, oops and oops again!
« Reply #12 on: February 20, 2013, 06:09:17 PM »
things are looking up all over..  Think I found where my problem was with the breaking drill bits, the larger of my jacobs chucks does not accurately grip smaller drill bits, switched to a smaller chusk and the bits run nice and true...well within a couple of thou any ways. Going back down to drill and tap another small hole, It took me 30 min to tap the last one.  This hot rolled steel feels kinda gummy when tapping so im taking it easy....wish me luck!!

Offline DaveH

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Re: dislexia oops, oops and oops again!
« Reply #13 on: February 20, 2013, 06:21:40 PM »
Dave,

A bit of cutting fluid may help.  :)
 :cheers:
DaveH

Offline DavidF

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Re: dislexia oops, oops and oops again!
« Reply #14 on: February 20, 2013, 06:45:38 PM »
Dave,

A bit of cutting fluid may help.  :)
 :cheers:
DaveH

  Dont worry I use plenty, this steel just doesnt cut real nice. I can only turn tap about a 1/4 turn then have to back it up so its slow going.

Arbalest

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Re: dislexia oops, oops and oops again!
« Reply #15 on: February 20, 2013, 07:49:34 PM »
It's been suggested elsewhere that it's better to use a spotting drill rather than a centre drill for accurate hole drilling.  ;)

Offline Mosey

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Re: dislexia oops, oops and oops again!
« Reply #16 on: February 20, 2013, 08:27:28 PM »
There may be something other than a drill chuck for holding taps.
Mosey

Offline mklotz

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Re: dislexia oops, oops and oops again!
« Reply #17 on: February 20, 2013, 08:37:47 PM »
There may be something other than a drill chuck for holding taps.
Mosey

Indeed.

http://www.modelenginemaker.com/index.php/topic,274.0.html
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Offline Mosey

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Re: dislexia oops, oops and oops again!
« Reply #18 on: February 20, 2013, 08:49:08 PM »
Well Marv,

The old soft shoe, like Ginger Rogers and Fred Astaire.



Mosey

Offline mklotz

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Re: dislexia oops, oops and oops again!
« Reply #19 on: February 20, 2013, 09:00:44 PM »
Well Marv,
The old soft shoe, like Ginger Rogers and Fred Astaire.

The sad thing is that we're both old enough to know who those people were.
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Offline DavidF

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Re: dislexia oops, oops and oops again!
« Reply #20 on: February 20, 2013, 09:33:38 PM »
Oh No no no, I'm not holding the tap in my drill chuck!!  That's not good for my drill chuck at all and I know better.   I got the other hole tapped out ok.  I'm used to working on bigger stuff and just having a bit of a learning curve going from real engines to model engines. Drilling small accurate holes is a new experience for me.  I think I have it figured out but open to any suggestions.    I'm happy I screwed up the first holes that are to guide the drill bit, hot rolled steel probably wasn't the best choice of material for the job. The drill bit feels much better when spun in the drill rod bushings I pressed in then milled back flush. What would you guys have used for material on something like this?  I'm considering a different fixture now, one that is located in the vise that will hold the stock so I can drill it for the rod bolts.  Process would be drill the stock for tapping, then clearance drill, then tap then part off the cap. Bolt the cap on then drill and ream rod journal, then drill and ream wrist pin, then profile outside of rod. Does this sound ok?   

Offline DavidF

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Re: dislexia oops, oops and oops again!
« Reply #21 on: February 20, 2013, 09:39:59 PM »
Marv,  good idea on the tap holders.  I see the need of them in my future.

Offline DavidF

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Re: dislexia oops, oops and oops again!
« Reply #22 on: February 21, 2013, 06:51:39 PM »
OK,  Have just about completed  the connecting rod jig, still have to do a little fitment in the bottom corners and then its done.