Mill tooling for reamers?

[ttoberer]

"that's a bummer John, you won't be able to tell when you poke through the toilet paper". Thanks Wayne, for pointing that out to me, it made my day LOL

Thank You, I needed that laugh after the long day at work I just had! Saturdays are rough at Whole Foods. Guinness is on sale, that helps as well!

[DMQuinn]

I assume you mean that, for you using a grinder, that the D profile is the only practical option of the two profiles to produce, since grinding away 1/4 of the reamer with a grinder would be rather challenging? ...

John

True enough, although I do have a milling machine and have made and used G or 3/4 reamers. By "limited production" I was only referring to the small number of bores that get cut with a given reamer.

Thanks very much, John, for explaining your technique of throwing up a burr. Well thought out.

I also appreciate your comments on the blind test, and agree that it would make more sense to do it with a simpler profile than an actual chanter bore.

[LiamO'Flynn]

How about a reamer that is milled 1/4 one side and 1/4 the other side ,this would give you two cutting edges.

Liam

[chris bayley]

It would have to be less than a 1/4 milled out if doing this - on the 1/4 but only 1/8 depth to keep stength and would effectively be a two flute reamer

I use a selection of different reamers including a ground down Lebel bayonet (Cruciform), 'G' (1/4 section milled out), 'D' section and also rectangular ones made from ground flat stock (gauge plate). These latter are made from 1/4"thick pieces to keep the rigidity and require machining on all faces at the narrow end. The reamers are a mixture of full length and also two part plus several short ones that I use for the area near the throat.

My method for making 'D' reamers is different to those described so far and does not involve either a saw or a milling machine in any form

Chris

[LiamO'Flynn]

Rectangular reamers are for bodgers and chairmakers and have no place in a pipemakers workshop..


Liam

[Mike Hulme]

Liam O'Flynn writes:

"Rectangular reamers are for bodgers and chairmakers and have no place in a pipemakers workshop".


Please explain.

[J-dub]

A chanter is really just a glorified leg of a chair so bodge away I say!

[LiamO'Flynn]

Sorry for the knee-gerk reply but I now see that this is not the thread to discuss the merits of rectangular reamers .But anyway regarding the double ground reamer,I think it could have some advantages over a D reamer. If the reamer is milled 1/4 thickness on each side this still leaves 1/2 the orginal thickness but 1/4 above each side of centerline ,which will leave alot more room for resharpening.Also being 1/4 above centerline makes it more stable in the bore when reaming .The two cutting edges speak for themselves.

Liam

[DMQuinn]

Sounds interesting, but I'm having difficulty picturing it.
Do you have a picture of the arrangement?

[LiamO'Flynn]

I dont have any photos so I was trying to post some diagrams but without success. Is there anyway to get diagrams onto a post ?


Liam

[hpinson]

The way I've been able to post images here, is to host the image elsewhere and embed the URI to that image between two img tags in the toolbar just above.

For example:

[<sic>img]http://path/to/image/hosted/elsewhere[<sic>/img]

Will display the remotely hosted image. Just be sure and remove the <sic> and it should work.

[LiamO'Flynn]

What I was trying to do was draw a little diagram in word and then cut and paste it but it wont work, but anyway the design of the reamer is fairly simple as I explained, it could also be described as a flat reamer except having curved sides.
Does the stability issue with D reamers not gets worse the nearer you get to the half-way point when grinding. Is there not too much “land” on one side which would force the reamer off centre because the pressure from the back is unsupported ( D< ) on the opposite side .
With a double ground reamer you have "land" opposite "land" and cutting face opposite cutting face.


Liam

[outofthebox]

Ideas like this need to be put to trial. The only way to test Liam's hypothesis is in a practical test - how does his reamer design perform set against those currently in use. The proof of the pudding is in the eating.

[billh]

Does the stability issue with D reamers not gets worse the nearer you get to the half-way point when grinding. Is there not too much “land” on one side which would force the reamer off centre because the pressure from the back is unsupported ( D< ) on the opposite side .
With a double ground reamer you have "land" opposite "land" and cutting face opposite cutting face.


Liam

Land opposite land may not be what you want - it enhances the burnishing/rubbing action while possibly preventing the cutting edges from getting a good purchase on the inside, unless there is a burr present.

I don't see a "stability problem" with the D section however - the land doesn't force the reamer off centre, but it does ensure that the contact forces are concentrated at the cutting edge where you want them. Put another way, the combined forces from the 'land' push the reamer edges, and only the edges, into the work, with minimum rubbing or stretching force, which is in this case a good thing. It also prevents the reamer from moving in any direction other than opposite the land. Since chatter involves periodic motion in opposite directions, I think the land acts as a stabilizer here, when compared with flatter reamer profiles. It's the presence of the land opposite the "missing" section of the D reamer that acts as a stabilizer.

On the other hand, the double hollow reamer profile would seem to be much more like the rectangular profile, from the point of view of contact forces and the range of motion within the bore, unless the hollows were of a very small radius in which case it would act like a double "channel" cross section. A three flute version, with land opposite each flute, might fare better, but it would be considerably more trouble to make and sharpen.

regards

Bill

[ttoberer]

D profile reamers work very well and are fairly easy to make and maintain,(I even made a few!) It cant hurt to experiment, but a good D bit reamer is tried and tested. I have found the bores also need very little finishing. with a little oil they work very well. a flat reamer will get most of the work done, then a D reamer will finish it up. or just skip the flat reamer ,which can leave the bore triangular. All these other types sound interesting , but D reamers work. just my 2 cents.