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Thread: Reamers 101
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31st March 2014, 07:38 PM #1
Reamers 101
I have had limited experience using reamers . Many years ago I replaced the king pins on my Dodge ute , I clamped the stub axle in a vise and used a proper mechanics king pin reamer set . It had a tapered guide that you fixed on each end of the bushes , and a adjustable reamer , it worked reasonably well .
What are the advantages of the fixed sized versus the adjustable reamers ?
http://www.ebay.com.au/itm/RDGTOOLS-...item519d8569a1
The TAFE course I did , reamers were not even mentioned Mike
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31st March 2014, 08:24 PM #2Cba
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There are many different reamers.
Under the heading fixed size reamers, there are machine reamers and hand reamers (hand reamers have a tapered lead and a square on the shaft end for a tap wrench). And each of these can be available either in linear size increments (for example ......... 9.99mm, 10.0mm, 10.01mm, 10.02mm,10.03mm.... or sized for a particular tolerance (for example 10mm H7 or 10mm P6 etc). The reamer can be straight or tapered. They can have straight flutes, spiral flutes or helical flutes. Depending on price, reamers can have an uneven number of flutes with regular or irregular spacing between flutes to reduce chatter tendency.
Adjustable reamers like on your picture, are adjustable over a very wide range (range like 0.5 or 1mm). These are invariably hand reamers, eg have a square at the shaft end for a tap wrench. One adjustable reamer can replace several dozen of fixed reamers, but it can take lots of time and trial cuts on test holes to properly set such an an adjustable reamer. Another advantage is that the cutting blades can be replaced easily. These reamers are quite solid and can take some abuse.
Then there are expandable reamers. These are hand reamers, but can be used well in the machine too. And can only be adjusted over a very small range (range something like 0.1mm, for example from 9.95 to 10.5mm). Quicker to set and use than the above adjustable reamers, and once set are more repeatable too. The downside is it takes more reamers to cover a given range, each expandable reamer costing more than a similas size adjustable reamer. And expandable reamers are less forgiving, more fragile than fixed reamers, and much more fragile than adjustable reamers. And when broken or worn cannot be easily repaired like adjustable reamers. In a home shop doing precision work, a set of expandable reamers is definitely more desirable than a set of adjustable reamers, but more expensive. I only own a handful expandable reamers, for the diameters I use most, but I love using them. Chris
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31st March 2014, 08:31 PM #3SENIOR MEMBER
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Mike, the advantage of fixed size reamers over adjustable is that you can drill slightly undersize,(.002 to .006") and then ream to size, and get that size. You can also get reamers which produce holes a few tenths of thous undersize or oversize, depending on the requirement of the situation. If in the case of wanting to dowel fittings together, you can have say 10mm reamed holes with 10 mm dowel pins which are an interference fit, and if multiple dowels are used, there can be only vanishingly small relative movement. I have read of others changing the size of a reamer a tenth or two both up and down, by burnishing the cutting edges of a HSS reamer using a carbide rod, and from what I read, it is possible to get very small adjustments to size, but I have neither done it or seen it done by someone else either.
With adjustable reamers, which are available over a more limited size range, you would have to do a series of tests, using similar material to your workpiece, where you reamed a hole, checked for size with gauge pins, then adjusted the size, ream another hole, test etc., till you got the size you were after. Then you would ream the hole or holes in the workpiece. You can ream blind holes in thinner material with fixed reamers, because you don't have the adjusting nut to accommodate, like you do on the adjustable variety, (machine reamers are best here, as they only have a very short tapered lead, compared to any hand reamer whether fixed or adjustable). One more thing, and apologies if you are well aware of this, but Never turn a reamer backwards if it starts to tighten, but keep going forwards, — you can start to withdraw the reamer, but you must continue to turn it in the cutting direction. Hope this gets you started,
Rob.
Chris has it covered with more info and he types fasterLast edited by Ropetangler; 31st March 2014 at 08:52 PM. Reason: I'm only a sloooow typist
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1st April 2014, 02:44 AM #4Senior Member
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My quick take on reamers is that if I want to make a hole of a certain size then I use a fixed reamer. If I need to open up a hole just a smidgin then an adjustable reamer is just the ticket.
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1st April 2014, 04:52 AM #5SENIOR MEMBER
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I agree with this. I had some steel bushings that were too tight to slide on a shaft. I used my adjustable reamer to increase the diameter ever so slightly and get a really nice zero (no discernible slop) slip fit. Up until this point I was wondering when I would use my adjustable reamers. I guess that is reamers for you. When you need them, they are very handy! One could increase the ID on the lathe, but for me I am likely to take it out a fraction too much on the lathe and have to live with the irritation that it is not quite right. Which would appeal a little too much to my OCD and I would be making a new part..
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1st April 2014, 08:15 PM #6GOLD MEMBER
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When I was a kid, my old man told me that if you ream a hole and find it ever so slightly too small, running a lap stone up each cutting edge will raise a burr. this will make the reamer cut slightly larger. I'm assuming not by much. Not sure if this was only in reference to white metal, bronze etc.
It's one of those conversations with my Dad that I remember from what must be 30 years ago. A time when I had zero interest in metal work and he was still gainfully employed as a fitter/turner.
I have never tried it. I don't think I work in tolerances that would benefit from such practices!
SimonGirl, I don't wanna know about your mild-mannered alter ego or anything like that." I mean, you tell me you're, uh, super-mega-ultra-lightning babe? That's all right with me. I'm good. I'm good.
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1st April 2014, 08:31 PM #7
Undersize? Whats that! I always seem to end up slightly oversize, i put this down to the cheap straight flute CTC machine reamers but then i had to ream .750" and got a nice used P&N spriral flute and it still ended up slightly over. The only possibility i can come up with is my T/S alignment was not spot on at the time.
Ew1915 17"x50" LeBlond heavy duty Lathe, 24" Queen city shaper, 1970's G Vernier FV.3.TO Universal Mill, 1958 Blohm HFS 6 surface grinder, 1942 Rivett 715 Lathe, 14"x40" Antrac Lathe, Startrite H225 Bandsaw, 1949 Hercus Camelback Drill press, 1947 Holbrook C10 Lathe.
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1st April 2014, 09:17 PM #8SENIOR MEMBER
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1st April 2014, 09:26 PM #9GOLD MEMBER
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Glad it doesn't just happen to me! Here's my account of how things go when I'm turning or boring to specific size:
Too small…… to small….. too small….. too small….. too small….. too small….. too small….. too small….. too small…..
B A N G!!
Too Big….
Girl, I don't wanna know about your mild-mannered alter ego or anything like that." I mean, you tell me you're, uh, super-mega-ultra-lightning babe? That's all right with me. I'm good. I'm good.
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1st April 2014, 09:34 PM #101915 17"x50" LeBlond heavy duty Lathe, 24" Queen city shaper, 1970's G Vernier FV.3.TO Universal Mill, 1958 Blohm HFS 6 surface grinder, 1942 Rivett 715 Lathe, 14"x40" Antrac Lathe, Startrite H225 Bandsaw, 1949 Hercus Camelback Drill press, 1947 Holbrook C10 Lathe.
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1st April 2014, 10:10 PM #11Cba
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If you just need the hole a tad larger (say 0.01 to 0.02mm larger on a nominal 10.00mm reamer) than wedge a match or toothpick or other wooden splinter between two cutting edges of a fixed reamer. This will increase pressure to the opposite cutting edges and cause them to take off a little more material. Resulting in a larger hole. It is a trial and error method, start with a small wood splinter, check fit, insert a larger splinter, check fit.... until happy.
Also, be aware that one and the same reamer will produce a different diameter hole depending on a number of factors.
- For example holes reamed in bronze are often a tad smaller than holes reamed in steel (it can easily be as much as 0.02mm undersize on a 10.00mm reamer).
- If lubricant is used plays a role
- How big the hole is predrilled can play a role, and what type of drill is used for this predrilling (idealliy pre-drilling for reaming is done with a special drill called a borer, borers have more than two flutes and are not center cutting). Reaming a typical 10mm hole is thus done like 1) drill a 9,5mm hole 2) bore this out to 9.8mm 3) ream this to 10.00mm (or whatever other tolerance).
- The reamer feed rate plays a role
- how sharp (or worn) the reamer is plays a role. When not used always put a plastic sleeve over the reamer to store away - the cutting edges are very sharp and very thin and very fragile.
- If done in a lathe from the tailstock, either use a special "floating" chuck, or be sure your tailstock is very!!! accurately aligned to the headstock center line. Be aware that most tailstocks are up to 0.05 to 0.1mm high when new. This matters a lot when reaming small holes - and small holes is what you ream most in a lathe, because larger holes above 8mm are easily and accurately made with a boring bar. It is small and deep holes that cannot be bored well, that are usually reamed in a lathe.
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2nd April 2014, 08:54 PM #12
deal
Hi
Serendipity or the planets have lined up for me I just bought this old set of Sutton reamers .... a case of being in the right place at the right time.... a bargain .
Question: Is it possible to sharpen the blades on these reamers , or are they a throwaway item ? Mike
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2nd April 2014, 09:11 PM #13SENIOR MEMBER
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Hi mike,
I am pretty sure you can get replacement blades for them.
Phil
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2nd April 2014, 09:44 PM #14Cba
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2nd April 2014, 10:22 PM #15
There is a simple way of making your own adjustable reamer... back in the days of smooth bore rifles, they used to ream the barrel with a straight square section reamer, you pack one side of the reamer with a piece of wood to get close to the diameter, then progressively add pieces of paper between the timber and the reamer until you get to the diameter you want.
Ray
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