Reaming thechnique

[john_reese]

If you trammed your mill and it is dead on and you keep a little tension on the quill clamp the work should be accurate.

On the lathe you can take a skim cut off he faceplate to make sure it is true before beginning the job.

 

[doc1955]

If you trammed your mill and it is dead on and you keep a little tension on the quill clamp the work should be accurate.

On the lathe you can take a skim cut off he faceplate to make sure it is true before beginning the job.

Unless you are using a jig bore machine I will bet you you can tram you mill head in dead on but the moment you move the knee up or down it will no longer be dead on it should be close but will not be dead on anymore. (just saying)

 

[almega]

And yet in several Youtube videos there are demos of reaming on a drill press where the ream is allowed to "wobble" to align with the hole. I doubt the drill presses shown are perfectly trammed. This is all very confusing to a relative newcomer like me. I just want to be sure my holes are aligned so a shaft can run true and there is good internal finish. I won't be making anything for NASA.

 

[doc1955]

If you have a sharp reamer and you let the part float it will follow the hole if you constrain the part and you are off you will get, more than likely a bell mouth or an out of round hole. Yes I have reamed a lot of holes on the drill press but not if I am trying to hold a tight positional tolerance hole.

 

[chrsbrbnk]

If you have a sharp reamer and you let the part float it will follow the hole if you constrain the part and you are off you will get, more than likely a bell mouth or an out of round hole. Yes I have reamed a lot of holes on the drill press but not if I am trying to hold a tight positional tolerance hole.

I'm a tool and die maker the approach for pretty decent accuracy for position in reaming would be put the center drill in a collet then drill say 1/32 under then bore with a flat end end mill leaving say .010 to ream out the big enemy's of ream acc. are trying to remove to much material, or the part really off location say .010 or more and or the part not being able to float to location . Ok now is the problem of reamed size versus reamer size there are a lot of reamers that right out of the box will ream up or down a tenth or two turning a press fit into a sled hammer fest or a fall thru kinda thing then there are cutting fluids there is no fluid that works for every thing but definitely use some form of cutting fluid and slow rpm the next problem is surface finish which relates to cutting fluid reamer condition speed in rpm and feed the thing to do is literally test EVERY reamer on a scrap of the same material with the fluid you intending ect. if size or finish mater which is probably why your reaming in the first place

 

[john_reese]

Reaming to size is an art. The final size of the hole depends on RPM, feed rate, type and amount of cutting fluid and probably several other things.. I worked on a job several years ago that required reaming the bore of a cast aluminum fan. The job was set up on a drill press. The part was held in a drill jig and the reamer was guided by a bushing. We could not hold consistent size. We finally gave up and bored the hubs on the CNC lathe.

 

[retailer]

As my reamers are very close to size at the tapered end, I need to get within .005" of the finished hole size before the reamer will enter the hole without a great deal of force so often I need to drill close to the final size then bore until within .005" of final size and then ream, my main reason for doing this and not boring to final size is that I don't have a huge amount of success getting repeatable results from my expanding bore gauges - there seems to be a bit of skill needed in using them. In the lathe it is not so bad as you can move the saddle back to give your self room but in the mill the expanding gauge is often at an odd angle, I can measure the hole with the expanding gauge 4 or 5 times and sometimes there might be 1 or 2 thou variation over the measurements which for close fit sliding parts can be too much, so if I use a reamer for the final sizing of the hole I'll know it is right on.