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View Full Version : Stonking great counterbore



John Stevenson
03-03-2004, 08:22 PM
Had to do a job yesterday on some large vibrator motors, no giggling at the back http://bbs.homeshopmachinist.net//biggrin.gif
Where the large bolts hold the feet down they had shuffled and left the top face concave.
The problem was do to where they were at the side of the case I couldn't get in with a milling cutter or boring bars as it needed nearly 10" of depth.

As it looks as this is going to be an ongoing job I decided to make a tool for the job. I cut a 13" long length off a 1.750" bar of cold rolled and machined an R8 taper direct onto the end.
I then milled a flat and a pocket on the other end to take one 3/4" wide inserts that I had kicking around, bolted this on with an M8 cap screw and fitted it to the bridgy.

Swept diameter of the insert was 2" which is enought to fit some very heavy washers to the new seating.
I expected some vibration and chattering at this length but although there was some it wasn't as bad as I had expected.
Leaving the tool to finish rubbing it cleaned up all 8 seats on two motors in about 45 minutes.
Most time was spent moving clamps and swapping the motors over as I can't lift these things. From start to finish the tool took about an hour, maybe a bit less and minimal cost as I had the insert.

http://homepage.ntlworld.com/stevenson.engineers/lsteve/files/counterbore1.jpg

http://homepage.ntlworld.com/stevenson.engineers/lsteve/files/counterbore2.jpg

John S.

[This message has been edited by John Stevenson (edited 03-03-2004).]

dvk
03-03-2004, 08:41 PM
I share in your joy of a job well done.

nice tooling.

wierdscience
03-03-2004, 09:28 PM
I guess that makes it a big vibrating tool http://bbs.homeshopmachinist.net//biggrin.gif


Or it could be a tool for fixing big vibrators http://bbs.homeshopmachinist.net//biggrin.gif

[This message has been edited by wierdscience (edited 03-03-2004).]

NAMPeters
03-03-2004, 10:11 PM
Looks like about a 5/1 L/D so it would be relatively stiff. Chatter probably has many small souces in the setup but the results are a servicable part and that is what counts. Good show!

------------------
Neil Peters

Forrest Addy
03-04-2004, 01:39 AM
Can't argue with resounding success. I suppose some will critique it though. Good work, John.

JCHannum
03-04-2004, 09:12 AM
Considering the length, it would not be too difficult to make a similar counterbore with a pilot on the end to fit the bolt hole, assuming it is still somewhat roundish.
Only critique is for Pete's sake man, sweep the floor. You do have one, I can see where it would be after application of a broom.

Randolph
03-04-2004, 10:14 AM
I was taught years ago by a man who grew up in the old railroad shops of the early 20th century that the capabilities of the shop are not limited by the machines but by the men operating them. You provide a good example of that.

John Stevenson
03-04-2004, 11:37 AM
This site is wonderful.
I read JCHannums post and saw where he was coming from, so I grabbed the bush and 15 hours later - a reasonably clean floor.

Once the floor was clean I found the counterbore cut a lot better and with less chatter, who would have thought that?

http://homepage.ntlworld.com/stevenson.engineers/lsteve/files/floor1.jpg

http://homepage.ntlworld.com/stevenson.engineers/lsteve/files/floor2.jpg

Joking apart, I had looked at a pilot but the state of the holes in these things are all over the place. They can be anywhere between 24mm if new up to 27mm and egg shaped.

If I had got stumpted I would have bored the end out about 1/2" diameter for about 3" long and bolted a 1/2" pin to a tee slot and used the pin as a male centre to hold it steady. I did think of this when I was making it but as usual, being in a rush I though I'd try it first.

John S.

Paul Alciatore
03-04-2004, 03:39 PM
John,

Great jobs on the counterbore and floor. Could you come sweep my shop now?

Paul A.

metal mite
03-04-2004, 04:22 PM
If the c'bore had not worked so well, you could have made a support with a bronze bearing to steady the c'bore shaft.

It could have been a z shaped affair to mount on the table beside the vvvvviiibbbbrrrraaaatttooorrr.

mite

lynnl
03-04-2004, 05:26 PM
Why John, that floor looks brand spanking new! Of course having that "protective covering" over it for years.., I guess that's to be expected.

Thrud
03-04-2004, 07:00 PM
John
Better be careful, the wife might walk in and think she's in the wrong shop!

Nice tool John. If you could have made it in two pieces a tapered tube with a end welded on should have been more ridgid - and if you filled it with powdered heavy metal it would not chatter much at all. Still, A very nice tool. You should blue or blacken it.

wierdscience
03-04-2004, 10:51 PM
Must be that spring is in the air for I too started sweeping the shop!You would be supprised how easy it is if you put and old pallet on the forklift forks and use it for a push blade,or in my case a crap plow http://bbs.homeshopmachinist.net//biggrin.gif

John Stevenson
03-05-2004, 04:56 AM
Damn,
Floor cleaning 101
Look for largish items in the crap like lathes and millers, shovel round these and taking large scoops with eyes closed lob the lot in the bin.
Theory behind this is if it's large and lost you never missed it did you ? or there would have been a search.
It also allows to to later take stock and buy more tools to make up for the missing ones.
It's a policy no one can argue with especially her indoors after all take a look in the cupboards and count plates and dishes, how many do you need to eat off?
Anyway I digress again.

Next take your magnetic based site drill and plug in [ you do have a mag drill?? if not see paragraph above ]
Taking care to steer clear of large items like freshly painted lathes, 'sweep' the floor with the base of the drill.
Hold over the bin and look for small irreplacable tools stuck to the bottom like those 10 number 89 drills you dropped and your wedding ring.
Decent rings don't stick to magnets - mine does.
I knew I shouldn't have started this cleaning bit.
Now I've got side tracked into sorting cupbard tops out and drawers.
Isn't it suprising what you find amongst all the sh....shed loads of items we save.
Oh look these a large thread grommet, that will make a very good attach.............

John S.

JCHannum
03-05-2004, 09:16 AM
I just went through that to a degree myself. I finished a project that had been on the bench for 6 months. It probably involved about 12 hours total time, but 6 months to get those 12 hours.
Anyway, cleaned off the bench and threw all those bits of scrap metal, some wood shims and short wire pieces in the trash can. Within 15 minutes, I had started rooting the wood and wire out. I'll probably dig some of the aluminum pieces out today for packing.
It helps to put post-it notes on the wall so you know what is in the trash. Saves time later.