If this is your first visit, be sure to check out the FAQ by clicking the link above. You may have to register before you can post: click the register link above to proceed. To start viewing messages, select the forum that you want to visit from the selection below. |
|
|
Thread Tools | Display Modes |
#21
|
|||
|
|||
Reaming
"Fortunat1" wrote in message
.. . OK, which brings me to another side of this, I guess. I'm hand reaming. By that I mean I'm putting a tap handle on the reamer, sticking the work piece in a vice and going at it by twisting the thing by hand. Needless to say it's nearly impossible to keep the reamer absolutely straight. Am I doing this right? One suggestion I got was to use my drill press by rigging something up to hand turn the drill spindle (no way I can get it to turn slowly enough for reaming) in order to get the reamer straight in. If you look at the top of your hand reamer, I'll bet you'll find a centering hole. Chuck up a tapered center in the drill press and use it to steady the top of the reamer. Rich S. |
#22
|
|||
|
|||
Reaming
"Rich S." wrote in
: "Fortunat1" wrote in message .. . OK, which brings me to another side of this, I guess. I'm hand reaming. By that I mean I'm putting a tap handle on the reamer, sticking the work piece in a vice and going at it by twisting the thing by hand. Needless to say it's nearly impossible to keep the reamer absolutely straight. Am I doing this right? One suggestion I got was to use my drill press by rigging something up to hand turn the drill spindle (no way I can get it to turn slowly enough for reaming) in order to get the reamer straight in. If you look at the top of your hand reamer, I'll bet you'll find a centering hole. Chuck up a tapered center in the drill press and use it to steady the top of the reamer. Hmm, good one. I could alos use the press to regulate the pressure on the tool easily enough that way.. |
#23
|
|||
|
|||
Reaming
What's so hard about reaming? I get reamed at work every other day
Scott http://corbenflyer.tripod.com/ Gotta Fly or Gonna Die Building RV-4 (Super Slow Build Version) Fortunat1 wrote: "Morgans" wrote in : Of course, getting a real chart with the tool, material, and the correct tool speed and feed speed or pressure it the "best" way to go at it. g -- |
#24
|
|||
|
|||
Reaming
Fortunat1 wrote:
"Morgans" wrote in : Of course, getting a real chart with the tool, material, and the correct tool speed and feed speed or pressure it the "best" way to go at it. g OK, which brings me to another side of this, I guess. I'm hand reaming. By that I mean I'm putting a tap handle on the reamer, sticking the work piece in a vice and going at it by twisting the thing by hand. Needless to say it's nearly impossible to keep the reamer absolutely straight. Am I doing this right? One suggestion I got was to use my drill press by rigging something up to hand turn the drill spindle (no way I can get it to turn slowly enough for reaming) in order to get the reamer straight in. Is this unneccesarily complicated? We're talking about .090 4130 here with a 5/16" hole. Wing attach and strut brackets for mounting onto a wooden spar for the most part.. You could chuck the reamer, and use the chuck key to turn it. A piece of 1/4" rod (cut threads off long bolt) also make a nice turning handle. -- "Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, with chocolate in one hand and wine in the other, loudly proclaiming 'WOO HOO What a Ride!'" --Unknown |
#25
|
|||
|
|||
Reaming
On Tue, 14 Aug 2007 02:03:28 +0000, Scott
wrote: What's so hard about reaming? I get reamed at work every other day I was waiting for that comment :-) a very good use for an old large reamer... clean it up and mount it in a varnished ornamental base. tack on the side a plaque. "for excellence in the field of motivation" make a really neat job of it and present it to the office bully at the next office occasion :-) I still have the reamer and plaque of one presented to the boss many years ago :-) stopped him in his steps. Stealth Pilot |
#26
|
|||
|
|||
Reaming
Ernest Christley wrote in
: Is this unneccesarily complicated? We're talking about .090 4130 here with a 5/16" hole. Wing attach and strut brackets for mounting onto a wooden spar for the most part.. You could chuck the reamer, and use the chuck key to turn it. A piece of 1/4" rod (cut threads off long bolt) also make a nice turning handle. Excellent suggestion. In fact the end of my tap handle did the job perfectly. Interpolating all the suggestions here, here's what I did to improve my reaming. First, I got some bits to cut the holes a tad larger than they already were. A 7.7 mm bit got me much closer to the final size. I found some 7.9 mm whcih were also undersize, but I was afraid it was a little too close and that the drilled hole might leave the corners of the triangular hole eating past the final reamed size. Second I used proper cutting oil. I also used the drill press suggestion which was perfect as it allowed me fine regulation of the pressure on the reamer and also kept it nice and straight going in. Now for the next stage. I have to install these on the spars. I have two possible plans. One, I drill it on the press ensuring that everything is as square as possible. the other that I use a made up drill guide which clamps around the spar and "feels" the hole in the plate on the other side. In either case I plan to use a bit of tubing with an OD the same size as the ultimate size of the hole in order that it fits in the holes on the plates so that after the first hole is drilled and I can slip a bolt in there I can drill the others in precisely the right place using the plate itself as a guide. In either case I'd drill out to a sixe under the final dia and then use the reamer to cut the final bit of wood away. Any pitfalls with this plan? |
#27
|
|||
|
|||
Reaming
"Fortunat1" wrote In either case I'd drill out to a sixe under the final dia and then use the reamer to cut the final bit of wood away. Any pitfalls with this plan? Sounds to me like you are seriously splitting toadstools. If you were to just drill the wood so the bolt fits, and then put some epoxy or varnish or whatever you want to use to make sure the bolt and wood do not interact, won't that fill the voids? I always thought that the strength in a fitting like this was in the squeezing of the fitting on the wood, not the sheer of the bolt against the wood. Am I wrong? -- Jim in NC |
#28
|
|||
|
|||
Reaming
"Morgans" wrote in
: "Fortunat1" wrote In either case I'd drill out to a sixe under the final dia and then use the reamer to cut the final bit of wood away. Any pitfalls with this plan? Sounds to me like you are seriously splitting toadstools. If you were to just drill the wood so the bolt fits, and then put some epoxy or varnish or whatever you want to use to make sure the bolt and wood do not interact, won't that fill the voids? I always thought that the strength in a fitting like this was in the squeezing of the fitting on the wood, not the sheer of the bolt against the wood. Not according to the info I have, anyway. I can't see the friction on the plates giving much strength at all. One of the engineering manuals i have is pretty specific about how the size of the bolt makes a large difference in regards to how much material it's pulling (iow a small bolt will pull through the wood more readily than a large one because it's applying the same pressure over a smaller area) Same manual goes to pains to point out that the hole should be as perfect as possible a fit in order to spread the load as evenly as possible over the material it's resting against. Seems to me I may have seen something similar in an old Sport Aviation and maybe one of the Bengelis books. But your question brings up a good point. How tight a fit do I want in the wood and the steel? Too tight will mean I won't be able to fit the bolts through the steel after painting. I wouldn't be as worried about the wood as the pourousness of the wood would allow for some retention. |
#29
|
|||
|
|||
Reaming
"Fortunat1" wrote Not according to the info I have, anyway. I can't see the friction on the plates giving much strength at all. One of the engineering manuals i have is pretty specific about how the size of the bolt makes a large difference in regards to how much material it's pulling (iow a small bolt will pull through the wood more readily than a large one because it's applying the same pressure over a smaller area) Same manual goes to pains to point out that the hole should be as perfect as possible a fit in order to spread the load as evenly as possible over the material it's resting against. Seems to me I may have seen something similar in an old Sport Aviation and maybe one of the Bengelis books. Is your engineering manual wood aircraft specific? I am NOT sure of how this applies to your situation, but I KNOW that with wood propellors, the amount of torque (squeeze) is critical in not having the prop slip. If the torque is not maintainted, it will allow the prop to slip around until it bears against the bolts and failure occurs. Anyone else? It would seem like the way I have heard that many people do it, is to fill the space between the bolt and the wood with epoxy. It spreads the loads, and prevents wood to steel contact, which is critical to prevent corrosion and decay. But your question brings up a good point. How tight a fit do I want in the wood and the steel? Too tight will mean I won't be able to fit the bolts through the steel after painting. I wouldn't be as worried about the wood as the pourousness of the wood would allow for some retention. |
#30
|
|||
|
|||
Reaming
Morgans wrote:
"Fortunat1" wrote Not according to the info I have, anyway. I can't see the friction on the plates giving much strength at all. One of the engineering manuals i have is pretty specific about how the size of the bolt makes a large difference in regards to how much material it's pulling (iow a small bolt will pull through the wood more readily than a large one because it's applying the same pressure over a smaller area) Same manual goes to pains to point out that the hole should be as perfect as possible a fit in order to spread the load as evenly as possible over the material it's resting against. Seems to me I may have seen something similar in an old Sport Aviation and maybe one of the Bengelis books. Is your engineering manual wood aircraft specific? If you read the literature, I think you will find that tearout is an issue for bolted wood connections on aircraft, so the bearing stress is important(and is equally applicable to metals as well). If the hole is oversize the bearing stress goes up. If the bolt size and hole size are reduced, the bearing stress goes up. So the bolts are generally sized based on the bearing stress on the wood, not the shear stress of the bolt. There was even some experimentation with aluminum and hollow steel bolts at one point. As to the importance of fit...from an older ANC and FPL study on bolted wood joints for aircraft..... "1) bolt holes with visibly smooth side walls have bolt-bearing properties far superior to those with visibly rough side walls; 2) in order to produce a smooth hole, the drill must be well sharpened and the rate of feed in drilling must be slow enough to enable the drill to cut rather than tear its way through the piece; and 3) in the materials used in this study, Douglas-fir plywood and Sitka spruce, the twist drill produces a smoother hole than does a machine bit. Because the area of wood in actual contact with the bolt is reduced, a bolt hole with its wall visibly scored or with material torn or otherwise removed beyond the true cutting line of the drill will be more seriously deformed at loads less than the proportional limit, will have a lower load at proportional limit and a reduced ultimate load, and will be more seriously deformed at the ultimate load than a hole with a smooth, truly drilled wall. " Further findings of the study were that machine sharpened bits were superior to hand sharpened bits, a slow feed was critical to getting the best hole quality ala one inch per minute with a twist drill was best. Also, it mentioned that the drill should be producing shavings, not small chips or granules, these latter being evidence the bit was tearing and not cutting the wood. Charles |
Thread Tools | |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
Reaming needed on aft wing attach point. | Boelkowj | Home Built | 0 | November 7th 03 01:30 AM |