Adjustable reamer. Any chance of getting what you pay for ?

[Smallfry]

I recently asked in the Wanted section, is anyone had an adjustable reamer they wanted to sell. Was offered a couple on loan, but as I don't really like borrowing tools, I thought I would buy one instead.
It is for a one off job, taking .007 out of the centre bore of an engine flywheel, so needs to be reasonably accurate, and leave the bore with parallel walls at 42mm. I couldnt think of any other way to do it, so thought this would fit the bill.
It is for an experiment really, so also didn't want to pay too much, so bought a cheap one on eBay. How bad could it be ?????

Very bad as it turns out. The concept is simple, but the execution is dire IMO. Unless I am missing something, I guess, having never used, or seen one in the flesh before, that all six blades should be equal in shape and size ? These are not, and vary in length my a couple of mm, so the collars do not grip them all, and also, tightening the collars results in the collars tipping. Measuring across the six blades all shows a different measurement, so no chance at all for any accuracy.

The threads are loose as a goose too, and the whole thing looks like it was made in someones back garden in rural India ........ which it probably was.

This, or course now leaves me with the problem of how to do what I wanted.

 

[addjunkie]

Ive a set of those, never really had any success with them. For the amount your wanting to remove would something high tech like a couple of bits of emery cloth glued to a bit of dowel in a drill not suffice

 

[Ian X]

I bought a Presto reamer years ago for one job, was an 8-9mm. It works a treat and is deadly accurate when set but was hideously expensive, I blotted from my mind how expensive, £90+ perhaps. Those Indian ones are probably as good as the Indian drill bits a friend sent me to try

 

[Smallfry]

Ive a set of those, never really had any success with them. For the amount your wanting to remove would something high tech like a couple of bits of emery cloth glued to a bit of dowel in a drill not suffice

I did think of that, and also a small flap wheel, but I think these would bell out the ends slightly, which I would like to avoid if possible.

I thought about one of those three legged cylinder hones, used for brake cylinders, but dont know if it would take enough off.

 

[pressbrake1]

I bought a diamond reamer off eBay last year

It was sand glued onto a rusty mandrel
Impressively bad

 

[Smallfry]

I bought a Presto reamer years ago for one job, was an 8-9mm. It works a treat and is deadly accurate when set but was hideously expensive, I blotted from my mind how expensive, £90+ perhaps. Those Indian ones are probably as good as the Indian drill bits a friend sent me to try

I have seen a new Presto jobbie at £130. but can't get my head round that at the moment.

I am also concerned that Presto stuff is not what it once was, maybe outsourced to the same Indian shed as this one Or maybe even fake.

If it was any good, I have some camshaft bearings that need doing, and also some tractor king pin bushes ..........

 

[Martin Hocking]

Could you not make a great big d-bit out of silver steel?

I presume you could buy has drill rod at that size but I bet that’s loads of money.

 

[Seadog]

Your reamer is scrap.
I've always used expanding reamers with pilots, not something that is going to work for you in your particular application, I guess?

 

[dave h 2]

The simple answer is buy second hand on ebay eventually or grind all the blades the same length and try it. Check the blades are the same depth as well.
You can't do .007" off the dia in one go anyway.
Wearing flipflops can only help in these cases.

 

[Kram]

0.007" is 0.18mm and certainally can be cut in one go, 0.09mm per side.

Too big for a lathe or mill to bore it out?

Do you have a lathe? Turn a fixed size reamer, a guide portion at the cuttent diameter followed by a step to the desired diameter, grind several flutes and clearance.

 

[Agroshield]

You can't do .007" off the dia in one go anyway.

I am not sure that reaming allowance is an absolute scale. I would surmise that what is possible or not depends on the diameter.

0.007" as a proportion of 1/4" is quite different to 0.007" as a proportion of 1 5/8".

It puzzles me a little why an adjustable reamer was chosen at all. Why not a standard, non-adjustable 42mm reamer (of known tolerance band) and be done with it?

Also, as this is a flywheel, the depth/length to diameter ratio is going to be very small (likely less than 1). That makes hand reaming a challenging task as it would be difficult to keep the reamer square to the hole centreline. With the flywheel in a lathe, even unpowered, and the reamer in an appropriate holder in the tailstock, you would have a lot more confidence in the alignment.

 

[graffian]

Your reamer is scrap.
I've always used expanding reamers with pilots, not something that is going to work for you in your particular application, I guess?

I have an adjustable reamer that was bought for the little end of a moped, he assumed I would have some idea about using it, which I didn't and I
turned the lovely new bush into something that resembled a cats ****. It was a Dormer reamer so I guess it was all my fault.
I avoided the things till ebay started and I couldn't resist a spiral adjustable reamer for 99p and I seem to have picked up a few others since
They do work, but I go in tenth increments otherwise the hole resembles a ring piece.

For some strange reason I bought a pair of completely useless Indian reamers with pilots, I knew they were going to be rubbish .
But I was shocked quite how bad they are, they look like a three year old hand ground all surfaces with an angry grinder.
The pilots - they were bought for reaming girder bushes - go on ******, the tapered bits - to go on the pilots- are loose as a loose thing.
Like mentioned above the blades are not all the same length.
I never did find out what the random bits of rusty metal included with the reamers was for.

 

[oldbikedavey]

Sounds like a jig-boring job....

 

[Ali]

I had this exact same experience with an adjustable reamer not long ago, took some photos and measurements and the seller held his hands up and refunded. If I recall the blades were really sloppy non the grooves as well as being different sizes. Gave in and spend £60 on a Dormer.

 

[Johnnybravo]

Stick it in a milling machine or lathe and bore it out

 

[Keith 66]

^^^ This or clamp it to a decent drill press & bore it with something, Flycutter? spill bore it? the latter was a gunsmiths tool used to bore shotgun barrels & chokes, a square bar with single cutting point & curved wooden spill down one side, by packing between the spill & the cutter bar the depth of cut was increased, apparently red rizlas for a heavy cut, blue for a light one! you would need an entry bushing to start it.

 

[pressbrake1]

Could you not make a great big d-bit out of silver steel?

I presume you could buy has drill rod at that size but I bet that’s loads of money.

Best plan for limited workshop
Nice fitting pilot

 

[Smallfry]

0.007" is 0.18mm and certainally can be cut in one go, 0.09mm per side.

Too big for a lathe or mill to bore it out?

Do you have a lathe? Turn a fixed size reamer, a guide portion at the cuttent diameter followed by a step to the desired diameter, grind several flutes and clearance.

We do have a sad and very tired Colchester Mascot here, but the clutch has gone. The flywheel is 13 1/2" diameter, and while it would go with the bedgap removed, it would need the alternate set of jaws (cant remember what they are called) and even if I could find them, I am not sure it would open that far.

 

[Kram]

We do have a sad and very tired Colchester Mascot here, but the clutch has gone. The flywheel is 13 1/2" diameter, and while it would go with the bedgap removed, it would need the alternate set of jaws (cant remember what they are called) and even if I could find them, I am not sure it would open that far.

Faceplate or temporarily tack weld it to something, which can be easily gripped in a 4 jaw.

Also, as this is a flywheel, the depth/length to diameter ratio is going to be very small (likely less than 1). That makes hand reaming a challenging task as it would be difficult to keep the reamer square to the hole centreline.

That is why it needs a guided section of a very good precise sliding fit, say 0.05mm smaller than the bore, provided the existing hole is good and not chewed up.

Could you not make a great big d-bit out of silver steel?

I presume you could buy has drill rod at that size but I bet that’s loads of money.

Many ways to do this, wouldnt need to be silver steel, and that may be difficult to harden that diameter. Even so, its not too expensive to buy thick O1 plate, I have quite a bit.

Braze or tig HSS to mild steel followed by turning/grinding. If turning, intermittent cuts are not a huge problem on a little lathe like mine, I have made several tools this way.

Turn a guide pin and fit a 42mm OD bearing with epoxy - more than adequate for the light cuts of this. Grind 1mm deep cutting edges in the OD. High chrome bearing steel would make a good cutter.

Large HSS step drills are cheap, grind to size.

 

[Melvyn Best]

Engineers blue to check contact area and very careful use of a flap wheel to remove most of the material followed by lapping the flywheel to the crank using valve grinding paste . I had a similar problem around 55 years ago on a very early Mini although I don’t think flap wheels had been invented then