help with jet bench drill please

[kross]

hi,

i've just bought a Jet JDP - 13 bench drill & set it up in my shed

i'm a complete novice with machines like this, but the intention is to make wooden boxes & hopefully mandolins

i'm very disappointed with the jet drill, though - there seems to be an awful lot of vibration, but i don't know what's normal for a drill like this - i've posted a video on youtube which i hope illustrates the vibration & i was hoping maybe some members here could have a quick look at the video & see if you think its normal/average or not

the vid shows a small piece of ply leaning up against the shank of a twist drill & being bounced up & down

any thoughts /suggestions would be very much appreciated -


youtube vid ; http://www.youtube.com/watch?v=y3ihoXgG ... detailpage
thanks
chris

 

[Tinbasher]

Are you certain your drill bit is dead straight?

Is it drilling unround (?) holes?

I didn't sound any worse than my drill press but then I have a cheap chinese BnQ jobby.

Tin

 

[Steve Maskery]

Hmm. I don't think that you little test is very demonstrative. What were you expecting the little piece of wood to do? It seems to me that it did just what one might expect.

The best way to tell if it is true or not is to use a DTI and a piece of silver steel bar.

S

 

[kross]

The best way to tell if it is true or not is to use a DTI and a piece of silver steel bar.

S

you lost me there i'm afraid! whats a DTI?

i feared my vid might not give much of an impression -i can feel a vibration in the machine as i use it.

 

[Steve Maskery]

OK. A DTI is a Dial Test Indicator.
You chuck a piece of proper round bar in the chuck and set the DTI against it. It will measure run-out to a thou, perhaps a tenth of a thou. If it's within a couple of thou, I'd say that was OK for woodwork.

How good is the drill bit? If that is a bit bent, it will give you vibration. My driil is a 1963 Meddings, the quill is ground to 1/10 of a though, and yet it shakes like mad with one particular drill - it's because the bit itself is not straight.

S

 

[t8hants]

Your test is a false one because the edge of your piece of ply, is in fact like a piece of corrigated iron in magnification, and it cannot possibly stay in one place. As has been suggested use a piece of bar that has been percission ground round, ordinary black will not run true either. From your vid the drill seems to run well within the expect norm, its a bench drill, not a milling machine. I would expect vibration as there is still a lot of mass revolving, plus I presume a couple of stepped pulleys and a drive belt, all of which have been balanced to a tolerance, not exactly, hece the vibs. Also I have never thought a standard jobber twist drill was the best tool for wood boring, but someone will correct me if I am wrong.

G

 

[kross]

ok thanks everyone!

my little vid wasnt really meant as a test - i was just trying to think of some way to convey my experience of the drill to other people

i'll buy a good quality drill bit for starters then, and see if that makes it feel any better - at the mo i dont think i'd feel very confident drilling, say, holes fpr the machines in the head of a mandolin with it - if not a "standard jobber twist drill " then what would give the best results?

i dont know if i'm expecting too much from this quality of machine, or if there's something i can do to improve it - i certainly feel disappointed with it at the mo!

thanks for the replies -if anyone else has any suggestions they'll be very gratefully received - i have to persevere with it , but am not quite sure how at present!

chris

 

[Steve Maskery]

Standard jobber twist drills are a very poor choice for clean cutting of wood, they are designed for cutting metal.

A good set of twin-lip and spur bits is a good investment. I have the Ax TiN set. It's good value, but not the best quality - it's the 12mm one from that that vibrates like mad and I haven't abused it. Some of the others in the set are fine, though.

For larger holes invest in some good Forstner bits. Yes they are expensive, but they do make a world of difference.

S

 

[9fingers]

For holes up to say 1/2" I suggest lip & spur wood drilling bits. There are cheap and nasty sets all over the place bt I have been very impressed by the ones sold by Wealden. http://www.wealdentool.com/acatalog/Onl ... ur_33.html

Above that size Forstner bits are my preference.

Many of this style of drilling machine suffer from lack of rigidity in the motor mounting and that plus a vibration in the belt(s) is the most likely source. small adjustments to belt tension might help. Run the belt with the least tension that gives low vibration and good power transfer. If it has not got cogged vee belts on then maybe changing to those might help (but it might be fitted with poly vee belts so no need to change those)

cogged belts http://www.medwaypt.co.uk/dunlop/images ... -belts.png
poly vee belt http://image.ec21.com/image/nash4728/si ... e_Belt.jpg

hth

Bob

 

[mbartlett99]

We have a small Jet drill press in the workshop and yes it vibrates - its not rubbish but it also isn't designed for high precision work. If its precision that you require drill undersize and then ream - with a proper reamer - to the required size. Dormer make quite good quality tools for this sort of operation.

 

[RogerP]

It doesn't appear to me to be any different than others of that type of drill press I've used.

I have noticed that the 12 speed models which have three stepped pulleys and two belts and are nosier and more vibration prone than the 5 speed models which only have two pulleys and one belt.

 

[kross]

thanks guys! obviously the first thing for me to do is get some good quality drill bits & see what its like with them

i did try different belt tensions & i think that did improve things so i'll experiment with the belts a bit more - & will take the chuck off & see if that makes a difference

 

[Benchwayze]

I love this forum...
Information overload! That'll teach you to ask questions!
Of course I am quite sure you are glad you did Kross, and welcome aboard.


Well done chaps.. I can feel a drill press coming on!

John :lol:

 

[kross]

I love this forum...
Information overload! That'll teach you to ask questions!
Of course I am quite sure you are glad you did Kross, and welcome aboard.


Well done chaps.. I can feel a drill press coming on!

John :lol:

nah - can never have too much info!

chris

 

[Stoday]

I drill a precision hole using a router and dowel drill Click

 

[kross]

I drill a precision hole using a router and dowel drill Click

thats very interesting - thanks!