Drill press for cutting 16mm holes

[Inspector]

galvernisednuts since you don't as yet have the drill press perhaps consider getting a mill drill right off the bat. They don't take up much more room than the pillar drill and already have the X/Y table. They also have better spindle runout specs and tool holding because of the draw bar. If you can get a dovetail column rather than round column machine you can raise and lower the head without loosing registration. Round ones can swing from side to side when changing height like many drill presses. I understand the higher up front cost but they hold their value and sell for more if you ever decide to move it on.

The use of Loctite (proper bearing and bushing retaining) is widespread and good enough that all the Cessna Sovereign business jets hold the flap bushings in the titanium flap brackets (14 of) with it. They are a loose drop in fit that have to have the Loctite to stay put.

My one concern lies with the reason the plastic links were used in the first place. I wonder if it was chosen because it has enough give in it to absorb shock while still being strong? Perhaps using a stiffer material like aluminium will transfer the forces elsewhere else and cause wear there instead? Motor bearings for instance. It might have been designed as an easy to replace part rather than other more expensive and difficult to replace failing parts.

You should study Aluminium alloys and their properties before getting any to make the parts from. Some of the alloys are weaker, soft and "gummy" to machine ranging up to harder, stronger (almost as strong as mild steel) and nicer to machine. Availability and costs factor into the choices.

Best of luck with your project and keep us posted.
Pete

 

[user 42626]

galvernisednuts since you don't as yet have the drill press perhaps consider getting a mill drill right off the bat. They don't take up much more room than the pillar drill and already have the X/Y table. They also have better spindle runout specs and tool holding because of the draw bar. If you can get a dovetail column rather than round column machine you can raise and lower the head without loosing registration. Round ones can swing from side to side when changing height like many drill presses. I understand the higher up front cost but they hold their value and sell for more if you ever decide to move it on.

The use of Loctite (proper bearing and bushing retaining) is widespread and good enough that all the Cessna Sovereign business jets hold the flap bushings in the titanium flap brackets (14 of) with it. They are a loose drop in fit that have to have the Loctite to stay put.

My one concern lies with the reason the plastic links were used in the first place. I wonder if it was chosen because it has enough give in it to absorb shock while still being strong? Perhaps using a stiffer material like aluminium will transfer the forces elsewhere else and cause wear there instead? Motor bearings for instance. It might have been designed as an easy to replace part rather than other more expensive and difficult to replace failing parts.

You should study Aluminium alloys and their properties before getting any to make the parts from. Some of the alloys are weaker, soft and "gummy" to machine ranging up to harder, stronger (almost as strong as mild steel) and nicer to machine. Availability and costs factor into the choices.

Best of luck with your project and keep us posted.
Pete

I'm still considering many options but the pillar drill was only £80 and pretty decent. The top spec saw has an alloy link but is a much bigger thing to match the size of the saw, so an alloy link should be fine but I'm also investigating many avenues including various composites, plastics albeit different types and oversize options too.
I'll update soon but with Christmas coming its probably early 2024 before i get some proper prototypes into service.
Incidentally a test piece was thrown together today in plastic and its actually gone together a thousand times better than i hoped. Material needs to be thicker but the principle was very simple
I've 2 mule machines needing rebuilt and quite rough with motor and bush vibration, they will be used for testing and given how unrefined and worn they are will be ideal worst case tests. They will be subjected to a lot of abusive cuts with thick and hard materials. Under tensioned blades etc, etc.
Fingers crossed

 

[ChaiLatte]

My one concern lies with the reason the plastic links were used in the first place.

Cheap and easy to injection mould. I suspect it is glass-filled nylon, similar to power tool bodies. Can we send one to your countryman AVE for a review?

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When field-testing any prototypes, a good investment might be a point-and-shoot thermometer. It would quickly identify if the top bearing becomes significantly hotter than the bottom one.

As an alternative to paraffin, so good he mentioned it twice, Isopropyl alcohol works well on aluminium. It has negligible clean up requirements (it both evaporates and is water soluble) and does not smell as bad.

 

[user 42626]

Well as a test, my first prototype is fitted and working, no vibration and running well.
I was already on the ball with the thermo gun but good suggestion. Top bearing is 22.5 degrees and lower bearing 24.8 degrees after 10 mins cutting.
Bottom bearing is always hotter as it gets full rotation.
The transparent material is amusing, i guess any cracks will be easier to see if they occur but as tests go I'm happy to see it in operation.

 

[Fergie 307]

Cheap and easy to injection mould. I suspect it is glass-filled nylon, similar to power tool bodies. Can we send one to your countryman AVE for a review?

----

When field-testing any prototypes, a good investment might be a point-and-shoot thermometer. It would quickly identify if the top bearing becomes significantly hotter than the bottom one.

As an alternative to paraffin, so good he mentioned it twice, Isopropyl alcohol works well on aluminium. It has negligible clean up requirements (it both evaporates and is water soluble) and does not smell as bad.

Never tried alcohol, and I have loads. I would have thought it would evaporate too quickly. Agree with clean up and smell though. I shall have to try it
Have always used paraffin as it works really well and is as cheap as chips. Should only need a tiny amount anyway. You could just use WD-40, it is just to stop the aluminium sticking to the cutting edge of the tool, which it will do very quickly if you don't use a lubricant of some kind. For small jobs I use the bottles that come with the boss lady's hair dye to drip it on.

 

[chaoticbob]

This saga reminds me somewhat of my experiences rescuing Kity 419 table saws - decent saws let down by using a nylon pinion engaging with a steel rack on the tilt/raise mechanism. The pinion fails well before the rest of the saw is past its lifetime. OEM replacement was outrageously expensive - about £60 IIRC. I was able to make a full steel replacement handwheel/gear replacement one-off for less. Cutting corners in the wrong places I suppose.

This looks like a very worthwhile upgrade to the scroll saws.

Given that the OP doesn't want to outsource or invest in a mill or lathe to do it 'properly', drilling/reaming slightly oversize and using a bearing retainer seems right to me. It's not a 'stuck together with Loctite' bodge . As mentioned upthread these compounds are used in much more critical applications.
Bob.

 

[Fergie 307]

This saga reminds me somewhat of my experiences rescuing Kity 419 table saws - decent saws let down by using a nylon pinion engaging with a steel rack on the tilt/raise mechanism. The pinion fails well before the rest of the saw is past its lifetime. OEM replacement was outrageously expensive - about £60 IIRC. I was able to make a full steel replacement handwheel/gear replacement one-off for less. Cutting corners in the wrong places I suppose.

This looks like a very worthwhile upgrade to the scroll saws.

Given that the OP doesn't want to outsource or invest in a mill or lathe to do it 'properly', drilling/reaming slightly oversize and using a bearing retainer seems right to me. It's not a 'stuck together with Loctite' bodge . As mentioned upthread these compounds are used in much more critical applications.
Bob.

I didn't suggest that the use of a bearing retainer like loctite is invariably a bodge, there are many circumstances where it is perfectly sensible. I just don't think this is one of them.

I do take issue with the idea that it is somehow cheaper to make a hole oversize then use a retainer, than to machine the hole the right size in the first place. The retaining fluid itself is not cheap, and is time consuming to apply, you then have to wait for it to cure. All potential disadvantages compared with making the hole the correct size and then pressing it in, so hard to see a cost saving, quite the reverse I would have thought.

In the example Pete gives I am quite sure the holes will have been machined very precisely, and that the use of a bearing which drops in and is retained with loctite is in order to address particular issues with the application. I am guessing the massive variations in temperature the parts will experience in service would be one issue that might make an ordinary press fit unreliable. I dare say there are other considerations, but I very much doubt it's done that way to save money.

We know from the OP's experience with the original part that the failure has nothing to do with the bearings working loose due to vibration for example, or any of the other myriad reasons for using a retainer. Like the example you give, it appears to be simply down to the use of a less than ideal material by the manufacturer in the first place, probably driven by cost. So over time the plastic becomes brittle and fails.

Hopefully we can agree that the proper way of doing this, in this particular application, is to cut an accurate hole and press the bearings in. Providing the hole is accurate, with parallel sides, how it's cut is largely irrelevant.

In aluminium alloy if he uses a suitable sized drill to remove the bulk of the material, followed by an adjustable reamer then there is no reason why he can't get the hole to an accurate, and repeatable, size for the bearing to be pressed in. If he only intends to make a few initially this method would be perfectly adequate, if time consuming. If the idea takes off and it looks like he will be able to sell hundreds of them, then he can invest in a mill or farm the machining out.

This also facilitates easy replacement at a later date. Bearing in mind that it's a woodworking tool, his customers are unlikely to have a bottle of 638, and cleaner, sitting around. These will cost more than the bearings themselves.

 

[AES]

Never tried alcohol, and I have loads. I would have thought it would evaporate too quickly. Agree with clean up and smell though. I shall have to try it
Have always used paraffin as it works really well and is as cheap as chips. Should only need a tiny amount anyway. You could just use WD-40, it is just to stop the aluminium sticking to the cutting edge of the tool, which it will do very quickly if you don't use a lubricant of some kind. For small jobs I use the bottles that come with the boss lady's hair dye to drip it on.

+1 for WD40

 

[user 42626]

Thanks for all the advice and support, I'm ready to start sampling prototypes in a number of different materials.
I'll draw this to a close for now as testing will be long term.
If I'm not back beforehand have a great Christmas everyone

 

[Fergie 307]

Good luck with it, and have a great Christmas

 

[ChaiLatte]

The transparent material is amusing, I guess any cracks will be easier to see if they occur...

From dimly-remembered school physics lessons, using a polarised filter can show up stress patterns in perspex.

The dimness of my recall is whether it needed any special illumination to achieve this and whether it was actually perspex or some other plastic.

 

[MikeJhn]

Just my 2p worth, lot of talk of drill press quill run out, most will fully extend the quill and then measure the run out, IMO that's not the way to use a drill press, take the table up to the non extended quill and drill bit, minimum quill run out and an accurate hole.

 

[cemannion]

Good evening everyone, I'm normally actively supporting Hegner scroll saw users elsewhere on this site but I'm here seeking some advice with equipment and tools for a specific metalworking task.
Early next year i plan to make a number of linkages from aluminium flat, approx 6 or 7mm thick 25mm wide, 80mm long.
Thats the easy bit.

I need to drill 2x 16mm holes in each one so i can press fit 2x 16mm bearings. I'll obviously measure these more accurately with digital verniers or similar.
The holes need to be a snug fit.
Is it possible to do this with a good drill press such as a meddings, fobco, tauco etc. if it has a good quill and little float then can i attempt it with something like a 15mm or 15.5mm bit.
I don't mind buying the drill as its a good tool for many of my normal straight forward jobs anyway and i appreciate the quality of old ones.
Also I can't justify a mill drill as they're pretty big and expensive.
I've tried all my local engineering firms for the work but as usual a lot of air gets sucked in and big prices mentioned including £50 to £80 upwards just for set up. I've even been attempting this task with a small privateer for over 3 months and still no results.
I could need more than a hundred long-term but at this stage just knowing if its possible will help
Many thanks

My two penny's worth is a morse taper annular broach holder to fit your quill and a broach to suite the size required. Amazon do reasonably priced ones