I need to drill several 36mm (1.4173") holes in some 2" square aluminum blocks for some linear bearings but I can't find a 36mm drill except with a MT4 taper shank. I am thinking to drill 1 3/8 (1.375") and using an adjustable ream to get to final size but .04 is a bit much to ream. Should I invest in a 1 13/32" reduced shank to get within .011 or is it feasable to use my gorilla machining technique?
It would help if you told us what machinery you have available to work with. Offhand, I'd suggest drilling undersize and then boring to 36mm. You could use either a lathe or a mill with a boring head.
- Michael
Just to be clear, that should have been: "You could use either a lathe, or a mill with a boring head."
(With the comma to separate the clauses.)
- Michael
Once apon a time, I needed to drill and bore a bunch of holes in some Ti (using bridgeport). I had all the good drills and such. It was taking way too long and sometimes chattered real bad.
I took a rotory table, mounted a fixture for holding the parts on location, took the handle off the rotory table, put on a pulley, mounted an electric motor to the table, drilled a 1/2" hole, put in a 1/2" end mill, turned on the motor, and cranked the X axis until .015" from final dia. then bored it to final size. This took a 20 min. job and turned it into a 5 min. job.
I quess what I'm tring to say is, Do you have a rotory table?
If you do, you could do the same thing minus the electric motor. Crank the table some, turn rotory around, crank some more, etc......
Maybe I should've asked before I wrote all this, Are you using a mill or lathe?
cheers, Jack
I have both a bench mill and a lathe but I should have said a bit more. I am drilling through the end of a 2"x2"x5" block. I don't have an endmill long enough and my Chinese boring head gets a nervous tick when it swings a bar that long.
I guess I will drill to 1 3/8 and bore to reaming distance on the lathe. I was just trying to avoid two setups. OTOH, I need 8 of them so I could go into home shop "production mode." :-)
Comma not needed except after multiple clauses... Two don't count...
They're needed when you want to make the distinction between:
You could use either (a lathe), or (a mill with a boring head).
Versus:
You could use either ((a lathe or a mill) with a boring head).
- Michael
Drill a starter hole then bore it out with a boring head. You might get an odd 'circle' if you drill and try to ream.
If you don't have a boring head, a cheap one would be usable as you would be measuring the hole as it was bored larger to the final size.
Assume you have a mill or a milling attachment to your lathe. (I don't remember :-) ) But the Lead pouring - I remember that!
Martin
Glen,
Having made some housings for linear bearings you may find some of these rambings relevant. To get smooth motion everything needs to be spot on, the ones I did were open type and only 2" long, for 3/4" shafts. If your going to do it on a mill tram the head first. If you drill I doubt if you could get the concentricity over that distance so you have little alternative other than to bore. I made up some boring bars for my boring head when I made my Quorn (T&C grinder) the longer bars flex and cut better when run slow.
On a lathe hold in a 4 jaw and you will also need a fixed steady with a cat head to center the outboard end, check run out in both the horizontal and vertical planes.
Bernard R
Glenn Ashmore wrote:
Yep! Anyone familiar with machines knows that you don't use a boring head with a lathe, the lathe is, by itself, a boring head of sorts, unlike a mill. The comma was, indeed, appropriate.
Harold
Frankly, for true precision, I prefer the nested parentheses. You won't find that usage in any style book, but there is never any doubt of the order in which to parse the elements of the sentence.
-- --Pete "Peter W. Meek"
Hi Glen, I'll do 'em for you. I'd bore them in the lathe with a 4-jaw. Good training for my newest tech. Send me the specifics.
When are we going sailing?
How about making a 1 inch diameter boring bare for your lathe and some way to hold it. Yeah one more thing to make, but a large diameter boring bar can be pretty long and not have too much vibration.
Dan
Except in certian circumstances. Long before I got my bridgeport with power down feed I had to bore out some cylinders for a steam engine. I had to take quite a lot of material out. Since my mill drill didn't have power downfeed, I didn't want to make 40 or so 3 inch deep passes by hand (on 2 cylinders) sooo.... I built a jig to hold the casting on the crossslide of my lathe, Put my boring bar in the head stock and used the lathe to rough them out to about .020 undersized.. And yes the holes were slightly oval because the carriage lifts on the back half of the cut .... after it was roughed to the .020 it was a simple matter to set them up on the mill/drill and make 1 pass to get them right on... Like I mention below, I didn't have to change to positionof the boring bar sothey are both identicle in diameter.
As for the original question, if you have a lathe, I'd take them to the bigest imperial drill you have (like the 1 13/23 you mentioned) and then bore to final. If jigged correctly taking the .011 out in one pass should be no problem and that means you can leave the tool position set so they'll all be pretty damn close to the same size.
--.- Dave
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