drilling an MT2 hole

I have been looking all over and found roughing reamers and finishing reamers for mt2 holes. yet I have found nothing about actually roughing out the hole itself except to bore the hole on a lathe. Well i do have a lathe SB 9A but the part i need to put this mt2 hole in can not be mounted on my lathe. It is a large jig for making another fixture . My question is is there such a thing as an mt2 drill bit to rough out the hole before reaming? and if not, what is the method i should use to make that rough hole? oh and if there is, what in hell is it called as I have been looking for a tapered drill bit but all i find is tapered shanks when I put the phrase in google or any other place. I have a very large drill press that I could mount this jig on but I need the roughing hole, or the method of how to do that.

Drill a normal hole and ream a little, clear chips, ream a little more, rinse- repeat.
Regards

Step drilling is arrived at with the simplest sort of math. MT2 is ABOUT 5/8 per foot taper on diameter. That's ABOUT .050" on diameter per inch of depth

Got a pad and pencil? Make yourself a sketch

What John said...step drill. Same process used for taper pins if you don't want to abuse your tapered reamer asking it to do something it wasn't designed to do.

Machinery's Handbook includes a section on step-drilling for taper pins as well to give you a picture of the process.

Buy an MT2 roughing reamer. They make those.

alternate solution without buying expensive dedicated reamers that may only get used once...

buy one of these- (random eBay link)
Solid Socket Sleeve Arbor 1" O D w No 2 Morse Taper Hole for Lathe Etc | eBay

and a 25mm drill,which will drill oversize a bit and put you right in the range to use an adjustable reamer and then press/loctite/solder the MT2 piece.

you could even just drill a 1" hole and weld it in place.

then at worst you would end up with a very useful drill and adjustable reamer which you will surley use for future projects.

iwananew10K said:

alternate solution without buying expensive dedicated reamers that may only get used once...

buy one of these- (random eBay link)
Solid Socket Sleeve Arbor 1" O D w No 2 Morse Taper Hole for Lathe Etc | eBay

and a 25mm drill,which will drill oversize a bit and put you right in the range to use an adjustable reamer and then press/loctite/solder the MT2 piece.

you could even just drill a 1" hole and weld it in place.

then at worst you would end up with a very useful drill and adjustable reamer which you will surley use for future projects.

Click to expand...

Funny thing is I did something remarkably similar to that. However i did not have the time to wait for that adapter to come in so i did the next best thing. I cut off a section of an mt3 to mt2 adapter and welded it above a slightly larger hole in a piece of very thick steel which i had drilled and tapped and then mounted the hole thing on my drill press and used it to cut some parts i needed for a project that needed doing without delay.The only problem with using even a big heavy duty drill press as a mill is the Morse taper sleeve simple will not hold while while side forces they are not designed for it at all. The mill holder simply falls out. So i held it in with upward thrust on a dead center as you can see in this set up . It worked perfectly. No I don't recommend it on a regular basis, but it did work and I now have the parts I needed for the other project.

So you were running the drill press sort of like an up-ended horizontal mill? Interesting idea.

gadget73 said:

So you were running the drill press sort of like an up-ended horizontal mill? Interesting idea.

Click to expand...

Thanks it worked i have my parts

Ok its an old post but I regard forums as repositories of useful ideas so here is my penny worth.

I am metal spinning, need to put an MT2 taper into the top of a metal mandrel ( = shaped solid metal part which is screw mounted on the metal spinning lathe ).

Its a metal spininig lathe so I have I have a tailstock but there is no carriage so I cannnot taper bore on this lathe hence I need to step drill.

My plan for step drilling is as follows.

Use my MT3 to MT2 adaptor ( it has an MT2 female ) to act as a registration guide.

Make up a drill bit depth stop with a set screw suitable to cover the range of drill sizes I will be using - in my case something like 14mm to 18mm - ok I admit the depth stop will be offset on the smaller drill but it does not matter as long as it is square - the drill will not be the thing spinning since I am drilling on the lathe.

For each drill size set the depth stop by inserting the drill bit into the MT3/MT2 adaptor making sure that the drill is positioned axially before setting the screw. Use a washer of known thickness each time if extra depth is required.

Start with smaller drill and work through the sizes re-setting the depth stop each time for each drill size.

I reckon the depth stop that I make up should probably have a bit of length to it - say 2.5 cm long with ID 18mm since it will be oversized for the smallest drill. I don't think its worth the hassle of making one up for each drill size.

I like this approach, no measurement and as long as the depth stop stays put it should be accurate.

I reckon registration against an existing taper is preferable to measurement or calculation, usually more fool proof.


Jonnie