Thread: Unusual grind shape on new adjustable reamers

I have bought plenty of unbranded cheap adj readers on eBay . From real small To 38 mm I had 3 arrive today in the 13 to 19 range ... upon inspection the blades are not straight sided. Normally regardless of weather they are set in the adjustment range the outer measurement eg 17 mm is consistent from one end to the other when useing calipers. And the Outer edge of each blade is straight .. but this time all three reamers have a dip near the top end. I will try to post a pic

Pic A IS what I’m used to seeing but u can see at pint B THE MEASUREMENT is 16. Where it should be 17 mm at point A B AND C. Has anyone seen this before ? I would like to know what I’m on about before I winge to the sender. Perhaps it’s ok. Perhaps as I gradually feed the reamers into the hole it gradually cuts eventually the 17 im chasing ?

Hi Steve,

It sounds a bit odd to me ! All the adjustable reamers that I've got, all have straight parallel blades, none, not even the big 25 mm plus ones have any taper. I do have several solid ones that are tapered at the end for maybe 30 mm - 40 mm or so. But they are machine reamers and some have Morse taper shanks.

I have a set from 6 to 32 mm from CTC tools and they are similar to the ones you describe.
If you squint hard enough you can see they are wider in the middle
Reamer.jpg
Measuring on my 17-19 mm reamer I got the following.
Let "A" = zero.
B is -0.29 mm
C is +0.26mm,
D is +0.21mm
E is +0.14mm

So sort of bow shaped with an overall difference of 0.55 mm between highest and lowest.

Somewhere I read that these are really designed for metal sheet up to a few mm thick but I have used them successfully for up to 50 mm long bores.

Thanks men. It’s looking like some people just make em like that , so I can just use em and if I like that design and result I am open to purchasing more should the need arise. If not I’ll just give em a miss and buy from my old suppliers. It’s just nice to know they are not a quality control stuff up

Hi Steve, Guys,

I would have thought that if used hand held they would rock in any long hole !

I’ll post feedback here once I use them so we can all know if they are to be avoided or if they are ok

Originally Posted by BaronJ

Hi Steve, Guys,

I would have thought that if used hand held they would rock in any long hole !

Yes I would have thought so but I haven't noticed that.

I’m a bit inexperienced and unprofessional with my use of adjustmentabke reamers . There are u tube vids showing how to adjust them but not a lot of fine detail about how to use them correctly. I try to take care to ensure the blades are seated evenly and accurately as i am doin up the nuts. I think in the smaller reamers it’s hard to see properly and there’s a lot of potential for dislodged or broken blades esp if I’m not careful with the amount of metal removal. If I have enough room and can get a boring bar in there it’s what I prefer . Or a solid reamer, and then adj reamer as a last resort if I can’t locate a solid reamer

A while back on the net I remember vaguely seeing something about a floating tool holder to stop / help misalignment issues on lathe tsilstock but I was busy and basically ignored it. But now I think it’s time to research it. I found this pic on the net I’m thinking of useing this system for perhaps , dies , taps drills and resmers , perhaps some experimenting will help me decide when it’s beneficial and when not. Occasionally I have removed a job from a lathe and used a cordless drill to hold the reamer and hoping the reamer will naturally find centre as I don’t trust my tail stock 100 per cent As soon as I saw this pic on the net I thought that’s a good way to start my weekend. If anyone has experience with floating tool holders , fire away ..... I have a mill. I will have to put some thought into the best way to accurately drill and fit those pins.

I’m aware I’ll only need a tiny bit of slop in my design. I don’t want this thing flopping around like a Motorcar tail shaft universal joint

Originally Posted by BaronJ

I would have thought that if used hand held they would rock in any long hole !

John,
I thought adjustable reamers were only for hand use?

Originally Posted by STEVEMORSE

I’m a bit inexperienced and unprofessional with my use of adjustmentabke reamers . There are u tube vids showing how to adjust them but not a lot of fine detail about how to use them correctly. I try to take care to ensure the blades are seated evenly and accurately as i am doin up the nuts. I think in the smaller reamers it’s hard to see properly and there’s a lot of potential for dislodged or broken blades esp if I’m not careful with the amount of metal removal. If I have enough room and can get a boring bar in there it’s what I prefer . Or a solid reamer, and then adj reamer as a last resort if I can’t locate a solid reamer

I've had my adjustable reamers for about 10 years and like you indicate, I use them mainly when I can't put the work in the lathe and use a boring bar.

Here are a few tips - some are obvious but one never knows who's reading this stuff.

They can only cut very small steps, typical in mild steel I adjust the locking collars by no more than one turn at each pass.
Avoid going backwards ie when backing out of a hole turn them in the usual cutting direction - sometimes when they jam you have no choice but to wiggle them back and forth, but once loose always turn them in the cutting direction.
Use lube, I use a light machine oil.
Keep them clean while using them.
Remember to tighten the adjustment nuts or they can really jam in the hole.

I've not broken any blades but I have lost blades from two reamers and could not buy replacements so had to buy complete replacement reamers - at least now I have plenty of spare blades for those.

I have since acquired a few straight and a couple of spiral reamers but of course they are rarely the size I need.

Originally Posted by jack620

John,
I thought adjustable reamers were only for hand use?

Correct

Hi Guys,

Yes adjustable reamers are intended for hand use, but that doesn't preclude using them in the tailstock at low speed and plenty of lube. I've done this many times, lowest back gear speed or using a lathe handle.